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Sept - American Radio History

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1. ru INVALUABLE FOR STRIPPING FLEX THE NEW AUTOMATIC OPENING BIB WIRE STRIPPER AND CUTTER easily adjustable for all standard diameters Plastic covered handles can also be used as wire cutter Recommended retail price 8 6 A RANGE OF SOLDERS IN HANDY DISPENSERS A REF ALLOY SWG 4A 60 40 18 3 Slze5 18 3 60 40 22 4j 1 Recommended Price From Electrical and Hardware shops if unobtainable write to Multicore Solders Ltd Hemel Hempstead Herts EX RENTAL TELEVISIONS TWO YEAR GUARANTEE 17 SLIMLINE 405 only I lo 0 19 SLIMLINE 405 625 39 Gns Carriage and Insurance 30 FREE ILLUSTRATED LIST OF TELEVISIONS 177 19 21 23 ALT RANGE OF MODELS SIZES AND PRICES DEMONSTRATIONS DAILY TWO YEAR GUARANTEED TUBES 100 REGUNNED Slim Line Tubes 1 10 17 and 19 109 6 21 and 23 129 6 J Normal Tubes 70 and 90 17 99 6 21 119 6 14 and other sizes 79 6 SPEAKERS lj 24 80 34 250 RECORD PLAYER CABINET 4 100 3 x 5 8Q 3b 8 49 6 3 3Q BRAND NEW Pk P 2 Transistors Mullard arches output Ei 7 6 OC8ID 2 OCBI s P amp P REE rans ston bg Cases 4 for I Size 94 x 64 x 34 P amp P 9 6 Ferrite Roads 3 6 6 and 8 complete with LW MW Coils P amp P FREE STRIP LIGHT TUBES 3 9 each 11 284mm 230 240 volts 30 watts Ideal for coc
2. Having trouble getting the right PLUG GARRARD SP25 Pack 107 5 Pin Din Plus 10l Pack 108 3 Pin Din 3 d mk Il 1 0 1 9 6 carriage Pack 135 Jack s nrw Normal price 15 11 4 T 130 nba sere E dj Single record playing unit ack 103 Loudspeaker Plug s d Features include cue and pause Pack 100 Phono Plug 1 3d and automatic pick up return and Pack 230 3 pin Socket 46d Pack 236 5 pln Socket re Pack 234 Loudspeaker Socket 6 d Speclal express delivery 6d per unit postage S A E for llst of plugs sockets drive belts ready made leads etc switch off Wlred with mains cable and 5ft twln screened stereo cable 5 pin plug 10 6 extra AP75 Complete with base and cover 25 plus 15 carriage PLINTH and COVER 5 5 h 3 Unbeatable Value pius 10 p amp p Suitable for AT60 SP25 3000 2500 3500 Superb finish Spindle can be left in position with cover on Cover of neutral smoke tint perspex ns avallable for AP75 SL99 SL75 6 17 6 plus carr Replacement Stereo DIAMOND STYLI 20v MATCHED EE SPEAKER 8TA STA 9TAHC GPs sts sts 15 SET 350 Ev26 GC8 each rec price 12 10 others on request p amp p 1 6 6 19 8 Countdown S Teak Cabinet 12 jus A speaker of out specifi plus 7 6 p amp p 13 5 x 8 125 elipti cal woofer coupled to a coaxially mounted 3 125 high frequ
3. ES Circuit css Fig 1 Conventional use of a g d o to investigate the resonant fre quency of a tuned circuit It is no use getting a dip on a hand held g d o and then taking the g d o across the room to a receiver and expecting the frequency to remain constant Checking Crystals When the g d o is used to check the fundamental frequency of a crystal a slightly different technique is used A few turns of wire are wound on a former which is slightly larger in internal diameter than the g d o coils The ends of the coil are connected to a suitable holder for the crystal Fig 2 but if it is o O NS co G D O Fig 2 Using a g d o to excite a crystal at its fundamental frequency expected that a large number of crystals having different size pins and spacings are to be checked it is suggested that a permanent board be made up with a number of different holders all connected in parallel The lowest frequency range of the g d o is chosen to begin with and its coil inserted into the crystal coil Tuning from the low end to the high end of the range very slowly a dip will occur as soon as the g d o passes the frequency of the crystal At this point the crystal is absorbing power from the g d o and it should begin to oscillate at its own natural frequency provided that the coupling between the coils is sufficient When the g d o is used to check a conventional tuned circuit the dip in grid curr
4. Pre aligned I F module and tuner to gether with comprehensive instructions guarantees success first time 12 volts negative or positive earth Size 7in x 2in x O a ky RTV C Q 4 Cron LIMM m m EU EE wende e EUN a Ghee u h a PREMIER STEREO SYSTEM ONE Consists of an all transistor stereo amplifier Garrard 2025 T C auto manual record player unit fitted stereo mono cartridge and mounted in teak finish plinth with perspex cover ERENHER PARRER and two matching teak finish loudspeaker systems Absolutely complete and supplied ready to plug in and play As ystei ONE above The 10 transistor amplifier has an output of 5 watts per channel with inputs for pick up tape and tuner also but with Garrard SP95 tape output socket Controls Bass Treble Volume Balance Selector Power on off stereo mono switch PREMIER Carr Brushed aluminium front panel Black metal case with teakwood ends Size 12 x 54 x 3iin high Amplifier PRICE 45 Gns 35 available separately if required 14 19 6 Carr 7 6 VERITONE RECORDING TAPE TAPE CASSETTES C60 59 1 Sfor SPECIALLY MANUFACTURED IN U S A FROM EXTRA STRONG min 21 PRE STRETCHED MATERIAL THE QUALITY IS UNEQUALLED j C90 90 2 AU TENSILISED to ensure the most permanent base Highly resistant to breaks N n 6 age moisture heat cold or humidity High polished splice free finish Smooth C 20 Ge 7 6 E for output thro
5. C pues a PW VIBRADO 25 50 ULTAR MPLIFIER ADGOLA Soldering Instruments add to your efficiency ADCOLA 64 for Factory Bench Line Assembly A precision instrument supplied with standard 3 16 4 75 mm diameter detachable copper chisel face bit Standard temp 360 c at 23 watts Special temps 410 c Additional Stock Bits illustrated available from 250 c COPPER AA B38 Y 3 2 mm a cie CHISEL FACE CHISEL FACE B 14 3 24 mm wll M 5 B24 i 475 mm faep MYER pro nsum a 0 B 12 E 4 75 mm EYELET BIT B58 dU 6 34 mm CHISEL FACE LONG LIFE a E S nus i te B 42 LL 475mm CHISEL FACE E B 38 LL 4 32mm CHISEL FACE JL E B14LL amp 24mm o 7m umm i B 44 LL CHISEL FACE SCREWDRIVER an oes TE 4 75 mm FACE Don t take chances We don t All our ADCOLA Soldering Instruments are of impeccable quality You can depend on ADCOLA day after day That s why they re so popular You get consistent good service relia toj bility from our famous therm aliy controlied ADCOLA Element and the tough steel construction of this ideal production tool Write for price list and catalogue ADCOLA PRODUCTS LTD Liege Tope rA Dept M ADCOLA HOUSE GAUDEN RD LONDON S W 4 Telephone 01 622 0291 3 Telegrams Soljoint London Telex eTelex Adcola
6. B88 BQ Sil Trans NPN PNP equivalent to J 0C200 1 2N706A BSY95A etc B60 10 7 Watt Zener Diodes Mixed voltages j H20 i 2 us 40 BY126 7 type Silicon Rectifiers 1 amp l 0 plastic Up to 1 000 volts 250mW Zener Diodse DO 7 min Glass Type AV 409 5 Good Complimentary Set NPN PNP Germ Trans Pak F 3 in SEND FOR OUR FREE LISTS and CATALOGUE OF ALL OUR PRODUCTS CHECK YOUR OWN EQUIVALENT WITH OUR FREE BUBSTITUTION CHART BUY DIRECT FOR LOWEST PRICE SAVE s s DESPITE RECENT _ PRICE INCREASES LATEST NEW amp IMPROVED jULIETTE NASOI8BA COMMUNICATIONS RECEIVER with AFC 5 BAND MAINS BATTERY SOLID STATE PORTABLE RECEIVER OUR PRICE 56 gns cash only 9 pip BFO OPTIONAL EXTRA ADD 35 O AM Band 540 1600 Kc s Full Medium wave cover O Marine Band 1 6 4 6 Mc s Shipping Hams SW etc O FM VHF 88 108 Mc s Radios 2 3 4 TV Sound Public Services etc O Aircraft 108 134 Mc s im Proved sensitivity Air lines and Ground Control O PB High VHF Band 148 174 Mc s TV Bound Fire Ambulance etc Taxis Shipping Fuel Boards Oil Rigs Gas and Electric Boards Local Hams Industrial and Commercial Mobiles Military aircraft etc DE PENDING ON LOCALITY FEATUREB 4 Dynamic PM Speaker Directional telescopic VHF aerial Internal Ferrite rod aerial Hluminated Dial size 94 x 53 x 4 Weight 5 bs Impressive and sturdy design i
7. 1 O O 03 20 3 j 2 3 TOL St 1 Off a baie BC109 j 2 Osc 2 p RA 3 Osc 1 R9 100k A 4 Osc 1 2 100kA C1 C6 C4 C9 5000pF C2 c3 BE 150pF ET iub Qc We 5000 5000 1 8 2kfl sA 102 0 01 10 01 BC109 BC109 Argo tur VRI Output pF J PF RI lt R2 SR3 BAS Socket R8 SR7 SR6 685 68 S10 1 C5 Ol SKI2RI C10S10 68 68 ka S kn SKA aml VR2 1 2 10 SkA SKA SkA pF 50 kn HF kQ i ve j Amplitude Output 7 preset control Fig 1 Circuit of the Two Tone Tester The use of a two tone audio oscillator unit in conjunction with a suitable oscilloscope is the accepted way of adjusting a single sideband trans mitter and it is convenient if the tones used approximate to 1000 and 2000Hz The phase shift type oscillator employing a ladder network is one of the simplest ways of producing a sine wave in conjunction with a single transistor The required degree of phase shift between input and output circuits necessary to ensure reliable oscillations at audio frequency can be obtained by using a transformer as the feedback element Control of the operating frequency is not easily achieved in this way however and it is preferable to dispense with the transformer and to use capacitors connected in series between input and output Resistors associated with the feedback capacitors complete the RC network t Circuit The complete circuit of the two tone oscillator is given in Fig 1 and will be seen to compris
8. 5 3 GE D40C1 4W Darlington Amp 13 6 Notes supplied FREE with orders P amp P 1 per order Overseas 7 6 Cash with order Mail order only JEF ELECTRONICS P W 9 York House 12 York Drive Grappenhall Warrington Lancs Money back if not satisfied COMMUNICATIONS RECEIVERS Ex Govt bargains in the 10 to 20 range Example B40 640 kHz 30 5 MHz cleaned checked aligned with circuit information 17 Carriage 40 England Wales Deposit on crate 30 Also Murphy CAS and Pye CAT first class ex navy receivers B4l CR300 PCR2 and others Money back guarantee Calibrators VI VMs headphones components at competitive prices SAE details Phone any time Soe welcome P R GOLLEDGE G3EDW Glen Tor Torrington Devon STD 08 052 2411 COMPLETE RANGE of Amateur Aire rato Communications receivers Chassis panels meters cabinets microphones etc Stephens James Ltd 70 Priory Road Liverpool 4 Tel 051 263 7829 EMSAC FOR ANTENNA SYSTEMS AND CONVERTERS Please send sa e for details of 2 metre converters antennas and transmatches for receiving and transmitting ELECTRONIC amp MECHANICAL SUB ASSEMBLY CO LTD Highfield House West Kingsdown Kent Tel W K 2344 oe Est 1943 JOHNSONS tei 24864 New CV2 a unique triple purpose VHF kit for the Amateur enthusiast Integrated converter receiver and tuner feeder Fantastic single trans istor performance Compr
9. AH goods are new and subject to the maker s guarantee We do not handle manufacturers seconds nor rejects which are often described as new aud tested but have a limited and unreliable life Business hvurs Mon Fri 9 5 30 p m Terms of business Cash with order only Post packing 6d per item Orders Over 5 post packing free Sarue day despatch by first class mail Any parcel insured against damage in transit for only 6d extra Complete catalogue of valves transistors and components with conditions of sale price 1 post free No enquiries answered unless S A E enclosed for reply M MM H M H a 9 P em 4 6 Rats 9 1 p m EM utto nt FANTASTIC BARGAIN OFFER Serenade istori fier full transistorised ampli i which comes complete with 2 10 x 6 speakers and the latest BSR 4 Spaad Stereo Mono Record Changer ced solid state amplifier M e E deep 14 transistors plus 4 diodes separate Bass and Treble 40 watts total Frequency response 15 000 c s o EASY TO INSTALL NG TECHNICAL KNOWLEDGE t REQUIRED pm Only Gns tb Credit terms available first monthly payment 3 6 2 followed by monthly payments of Ys Total Credit Sale Price 33 18 Welcome Send 4 3 8 today m mena O T PLEASE SEND ME FREE DETAILS DF YOUR RANGE NAME ccc ccccccctccsrcencatcan ace A nto once vt teen tersctecccatat sata mas aha da nt AO LO
10. 13 17 GARRARD SL 65B 19 6 GARRARD SL 75B 35 12 GARRARD SL 958 45 9 GARRARD 401 me 31 14 GARRARD SL 728 30 2 GARRARD 3500 with GKS Cartridge se 15 15 GOLDRING GL69 25 1 GOLDRING 69P 33 11 GOLDRING GL 75 36 8 GOLDRING 75P 46 18 GOLDRING rere for esp and 75P 4 4 GOODMANS 3025 37 14 PHILIPS 228 19 19 PHILIPS GA146 29 19 PHILIPS 217 32 0 PHILIPS 202 Electronic 64 0 THORENS TD 1 75 17 THORENS 105AB 120 3 THORENS 150A Mk II 43 12 THORENS 150AB Mk I 47 8 THORENS TD 124 11 46 15 Bases plinths and covers stocked SPEAKERS ARENA HT 27 18 18 ARENA HT 28 17 17 ARENA HT 21 10 10 ARENA HT 7 19 19 ARENA HT 10 22 1 ARENA HT 20 32 11 ARENA HT 26 78 15 84W DM3 63 0 B amp W P2H 94 10 B amp W DM1 32 0 CELESTION Ditton 10 21 3 CELESTION Ditton 15 29 0 CELESTION Ditton 25 59 17 DULCI AS 3 8 8 GOODMANS Malesta i pg O GOODMANS Maxim 20 7 GOODMANS Mezzo Il 30 18 GOODMANS Magnum K 40 2 GOODMANS Marimba 24 O0 GOODMANS Mambo Ee 005 GOODMANS 3005 pain 25 0 KEF Celeste 99 0 KEF Concord 43 10 KEF Concerto KEF Cresta LEAK Sandwich LEAK Mini Sandwich LOWTHER Acousta wlth PM6 a LOWTHER Ideal Baffle es Special pace 21 Qio d4euwoa ad Q 4 4 00n 0O0o wu0 DNRADO cA OO GQo OooooooooooCcCowoooooooooo 10 19 11 19 11 12 14 9 28 19 37 19 26 10 24 19 11 19
11. 8 PCR 0014 QQVO3 o Urso 7 8 YT 6 n TO 7 8 lusa 7 RE aC 2Y8 PCLa8i 10 i UFR OSEE GEN MB meman agm ade IIO BL ETICA ES d pad e af Ey f wi T h z e 1 Ei 4 f gt 13 UL4 12 MA 18 ews 186 aies om ies Bo sane tye ago 19 eean So nese ee bees Qe Ea aaa IAE 18 1 a 4 As lt a sm abe ow e 5 E 4 3 3 t GSLzGT 98LYGTS 3503 RD E EF40 10 EZ 5 8 PCLS5 9 6 15 UMA 8 6AB4 8 6 BUYS 8j GSLTWT 8 8 J28L7GT8 3505 74 CBLI 16 EBF83 8 6 SF EN tas Mer a YT SNIEGT 28NTGT8 35D3 BL H 89 6 6 EF4 12 6 EZ40 9 PCL86 9 6 TTUI f GAP4A 8 6 6CY 12 GSNTNT 6 I28N7 T8 do Da i 18 CBL i 17 EBF 1 ER qf ma 8 PELAR 17 Trio 80 UTS 10 6AG7 7 6 Ds 8 USQT 8 I28Q7 8 35LaiT 9 8 CY3 T ECs 10J 2 j ID REM VE HE 3 DC iH T 7 2ST 25 W is Im EC86 12 EFBO 5i EZ80 5 8 PCLA00 18 UlIs 20 13 fo 6AHG 10 8DCrH 13 6 GSH 716 1287 f 8 6 ASWA 5 TARL 11 19 EF83 10 EZ8L 5 6 PCLROL 15 8 U20 13 6 UY 11 BAJS 5 9 BDKG 8 6 KTS 6 8 12X4 8 3523 1l j DAF 6 EC8s j EF53 v Ges 15 U 41 8j ci 5 DQG jai 7 35280 5 DAFY EC90 6 EF85 7 EZ90 5 PD500 30 25 j AKo 6j ADQGI 12 SER pol aobi 18 aofsur v Dales 27 Hos 66 Erao gia deloc100 ERRMDEM ues d Eya 10 6AKt 11 6 6DR4 15 SOS Loop 302507 7 6 DAU 7 9 EC82 6 He sees a E D
12. Capacitors C1 0 005uF 500V disc C13 0 005uF 500V disc C2 0 005uF 500V disc C14 0 005uF 500V disc C3 100pF 500V C15 35pF 500V 1 S M C4 0 0054F 500V disc C16 0 005uF 500V disc C5 0 005uF 500V disc C17 0 005uF 500V disc C6 0 0054F 500V disc C18 0 05uF 500V C7 0 05uF 500V C19 1500pF 500V C8 0 005uF 500V disc C20 1500pF 500V C9 100pF 500V C21 1500pF 500V C10 35pF 500V C22 0 005uF 500V disc C11 10pF trimmer C23 0 0054F 500V disc C12 500pF 500V 1 C24 0 0054F 500V disc S M V C1 2 3 3 gang 75pF per section Jackson E3 Inductors L1 Blue Range6 L2 Yellow Range 6 L3 Red Range 6 Denco miniature dual L4 Yellow Range 3 L5 Yellow Range3 Jj purpose Valves V1 3 EF80 or EF184 v2 ECF80 V4 ECC84 Miscellaneous Chassis 9x 5x21in Slow motion drive and knob 3 B9A Valve holders and screens 2 co axial sockets Tag strips 4 pin socket A number of paging stations is given but this is only a few of the many presently transmitting those listed having been received by the author KIF 651 Ft Lauderdale Fla 35 58 MHz KIY 508 Orlando Fla 35 22 KEC 519 Rochester NY 35 58 KCC 482 Pembroke N Hamp 35 22 KQD 303 Detroit Mich 35 22 KIQ 510 Jacksonville Fla 35 58 KIM 905 Charlotte N C 35 22 KGC 400 Scranton Penn 35 58 KGC 266 Allentown Penn KGC 293 Philadelphia Penn 35 29 KKI 445 Houston Tex 35 58 WWA 335 San Juan P Rico 35 22 KKM 248 Oklahoma City Oki 35 58
13. AF114 5 j BC184L 3 BFW58 5 6 NKT122 10 NKT244 31 NKT20329 6 8 ST140 3 2N744 6 2N3710 2 3 OAZ234 10 AF115 5 BC212L 34 BFW59 5 NKT123 9 6 NKT245 3 NKT20339 6 4 ST141 Si 2N911 10 2N3711 2 6 OAZ247 10 AF116 5j BCY10 10 7 BFWS60 4j6 NKT124 6 5 NKT262 4 3 NKT35219 15 9 ST 9 9 2N914 3 11 2N3819 7 SD19 Td AF117 5 BCY12 12 BLY47 31 3 NKT125 4 8 NKT263 4 8 OC19 5 T1407 9 8 2N918 B 5 2N3820 189 TD716 12 AF118 810 BCY30 5 BS05 10 NKT126 4j NKT264 4 3 OC20 19 6 TIS44 1 9 2N929 5 3 2N3826 6 1N34A 4 E AF121 6 BCY31 5 6 BSX19 33 NKT127 10 6 NKT265 5 5 OC22 8 TIP31A 12 4 2N930 6 2N3866 25 1N60 4 AF124 4 2 BCY32 10 BSX20 3 3 NKT128 40 NKT270 6 OC23 8 7 TIP32A 14 10 2N1131 6 11 2N4037 15 2 1N84 4j AF125 4 2 BCY33 4 BSX21 76 NKT129 8 6 NKT271 2 10 OC24 B V205 20 2N1132 7 9 2N4058 3 4 1N82A 9 6 AF126 3 6 BCY34 5 BSX60 12 7 NKT135 6 1 NKT272 2 10 OC25 7 6 V405A 9 3 2N1302 3 7 2N4061 4 1N87A 4 6 AF127 36 BCY38 6 BSX61 Tid NKT137 6 1 NKT273 38 OC26 6 6 40250 10 9 2N1303 3 7 2N4062 4 6 1N191 5j AF178 9 6 BCY40 10 BSX75 4j NKT141 10 6 NKT274 2 10 OC28 12 40309 6 6 2N1304 411 2N4287 3 1N914 1 9 AF179 11 6 BCY42 j BSX77 6 NKT142 10 NKT275 3 4 OC29 15 40310 9 2N1305 4 11 2N4288 3 IN4148 1 9 AF180 12 6 BCY43 BSX78 6 6 NKT143 9 6 NKT276 36 OC35 9 40311 6 9 2N1306 6 2N4289 3 1544 1 9 AF181 8 6 BCY54 76 BSY27 4j NKT144 8 NKT279A 2 6 OC36 12 6 40312 9 6 2N1307 6 2N4290 3 1510
14. ACOS GP9L at 7 8 1 Nu other types at present aml no 78 rpm available in auy type PICK UP CARTRIDGES All fitted Styli and Standard fittings Mono GP67 2 15 Stereo cumpatible Mono which also plays Stereo records wWonaurally with min wear GP91 SC 21 latest Stereo GP93 25 6 Ceranic Stereo top quality for expensive outfits GP94 38 8 souctone stereo 9TAHC diamanl fitted cartridge 55 all at 1 5 More diatruml types in list Goldring cartridges in stock PP3 ELIMINATOR A C 17 8 1 6 TWO STATION TRANS INTER COM Excellent baby alarm Instant easy fitting with leads plugs aml battery All you reduire 52 6 TRANSISTORISED AMPLIFIER 3 watt 9 operation 45 6 1 6 Extra High Turque MINI MOTOR 4 tu 12V 14 x iiu 5 1 9 000 r p m SUBSTITUTION BOXES Capacitance 25 6 1 6 Resintance 82 8 1 6 Both full range and complete Full details in list TEST PRODS Flexible uubreakable 24in Red and Black leads thin 44in prods 12in plugs 4 9 1 CROC CLIPS Plated with screw or with red black hndles 6d each 5j doz 1 Many other types in list RECORDING TAPE Finest quality British Mylar STANDARD din 600tt 7 8 fin 900ft 10 7in 1900ft 11 8 LONG PLAY Sin 900ft is Sin 1200ft 11 8 Zin 1800 t 18 1 3 reel Still the finest quality and value obtain able MICROPHONES CRYSTAL MICO9 Desk 18 8 MEC45 curved hand grip 17 8 Stick 60 90 8 1 6 each type Cream plastic hand typ
15. CR coils 10 28 25 e arr Extra coi red p R 30x 8 please SUPR tick as required 1 enclose ch ind M O IP O poe d eec raa nat NAME pm po o a ADDRESS 777 Wir ES HE paths of progress are T many and devious Woe betide the inventive gambler who stakes his all on a tech nical dead end Pitying progress watches the John Logie Bairds picking up the shards of mirror from a dusty floor and sweeps on to electronic miracles that we unfeeling fellows take in our stride The rewards of progress come closer home Henry is inspired this month by a recent visit to a Mullard Film Show where Ian Nicholson was in fine form chiding his audience because they dared to query the reliability of integrated circuits and were so reactionary as to want plug in devices Plugs and sockets are a tech nological cul de sac we were given to understand Despite the arguments of some industrial electronics boys who were slum ming in Bristol that night the signposts decidedly pointed to a solder in de solder out future with aspirated soldering irons and a ruined chip What does it matter if you have to break it to take it out said Mr N If you test intelligently you will know it is faulty before you get to that stage The emphasis must be upon logical diagnosis But of course the implication was that things never went wrong He can be a ton
16. POSTAGE PACKING amp INS ON ALL ABOVE 1 UP TO ll 12 x OVER PAID MULLARD STACK F W BRIDGE 24 100 PTV 39 6 3 ELECTROLYTIC CONDENSERS 7 dsisit ot wavy types trom 61 ench SUB MIN TRANSFORMER Output 3 Q for OC72 ete 2 9 driver 3 up to 6 either 1 MULTIMETER 20 0000 V D C 10 000 27V A C 0 5 25 50 500 1K volta D C 10 50 100 500 LK volts AC 40 504 A 2 5mA 950mA D C 40 6K 0 5 megh 10 F 00L1mtd Imfd 20 toxzudB Cemplete with test leads aud iustructiona Over load protected 1070 mode with every refinement 4 10 0 2 6 JUNIOR MODEL at 47 6 2 6 1000 Q V dexcribed in free list Spec subject to slight variation SOLDERING IRON Slim Mot British High speed sfin all parts replaceable fully guaranteed for professional radio and general D 1 Y nse 19 6 1 6 DIAMOND STYLI Espiacements for BSI TUSLP TUS S and TOSLP STEREO COLLARO O RONETTE BF4 LP GARRARDGC LP and GCRLP ACOS GP665 07 all at 7 8 each 1 ACOS GP73 and GP91 BSR ST4 ST3 ST5 STR ST9 SONOTONE 8TA STA and STAHC PHILIPS A4 33085 3060 3063 3066 3301 3302 3304 all at 15 1 All are of the very highest quality DOUBLE DIAMOND Types T you don t use the 78 side this is the best huy now available only in S T4 ST3 ATS STU STS ITA YTAHC 3306 GP9l for GP92 93 and 94 Cartridges aud GP91SC for GP918C cartridges 30 each 1 SAPPHIRE all the above 7 6 types only also AGOS GP37 at 3 3 each 1
17. Size 24xl xlOin P td 9 19 9 size 25 x 16 x 101in 6 19 9 lift and cut controls 3 input sockets for Mike iram Radio or Tape Input selector switch Output for 3 15 ohm spkrs Max sensitivity GV Output rating 1 H F M Fully enclosed enamelled case 91x22x lin Attractive brushed sliver finish facia plate 102 x 3Hn and matching knobs Complete kit of parts with full wiring 7G diagrams and instructions NS Carr 7 6 OR FACTORY BUILT with 12 months tee 8 18 8 INTEREST CHARGES REFUNDED On Credit Sales settled in 3 months THE YORK HIGH FIDELITY 3 SPEAKER SYSTEM R C TFMI SOLID STATE VHF FM RADIO TUNER 4 ut es Moderate size only 25x14x10in COMPLETE KIT 20 Gns E W 200 2507 A C Mains operation Sharp A M Response 30 20 000 c p s Impedance 15 ohms zx Rejection x jr Drift free reception yr Output ampie for Performance comparable with units costing Carr 12 6 any amplifier approx 500 m v ye Output tor feeding considerably more Consists of 1 12in 15 watt Baes unit with cast chassis Roil rubber cone surround for ultra low resonance and Ceranic magnet 2 3 way quarter section series cross over system 3 8 x bin high flux niiddle range speaker 4 High efficiency tweeter 5 Appro priate quantity acoustic damping materia 6 Teak veneered cabinet 7 Circuit and full instructions Terms Dep 3 Gns and 9 monthiy payments 45 6 Total 224 Gns DEMONSTRATIONS A
18. The Z 50 is completely interchangeable with the 2 30 and can be used in all Z 30 applications 2 30 Z 50 Built tested and guaranteed Built tested and guaranteed with circuits and Pedi QUO p with circuits and uaran tee 09 6 Manual manual STEREO 60 Pre amplifier and tone control unit The Stereo 60 is a stereo preamplifier and control unit designed for the Project 60 range but suitable for use with any high quality power amplifier Again silicon epitaxial planar transistors are used throughout and great attention has been paid to achieving a really high signal to noise ratio and excellent tracking between the two channels Input selection is by means of push buttons and accurate equalisation is provided for all the usual inputs The tone controls are also very carefully designed and tested ACTIVE FILTER UNIT fish Pass and Low Pass For use between Stereo 60 unit and to Z 30s or Z 50s the Active Filter Unit matches the Stereo 60 in styling and is as easily mounted It is unique in that the cut off frequencies are continuously variable and as attenuation in the rejected band is rapid 12dB octave there is less loss of the wanted signal than has previously been possible Amplitude and phase distortion are negligible by reason of the careful design and generous negative feed back employed Supply voltage 15 to 35V Current 3mA H F cut off 3dB variable from 28kHz to 5kHz L F cut off 3dB variable from 25Hz to 100Hz
19. Two inputs are provided for guitars ie two instruments bass or treble can be plugged in and for which independent volume controls are provided There is also an input for a microphone which may be high or low impedance depending on whether a microphone transformer is used The microphone channel has its own volume control and being quite separate from the guitar channels is not affected by the tremulant system master volume control is provided for all channels The completed Vibrasonic amplifier which utilises two 12in speakers to handle the output of 50 watts r m s The function of the tremulant system is visually indicated by a front panel lamp which shows the tremulant speed and depth However when the tremulant is switched off the tone networks of the tremulant amplifier can still be used as a tone control There is also a separate treble lift control in the guitar input pre amplifier which together with the tremulant tone control can provide the very sharp tonal quality favoured by pop guitarists There are two optional facilities One is a foot switch on off control for the tremulant and the other a foot pedal controlled wah wah effect Foot switch control of the tremulant simply requires an extra jack socket and a foot switch with a press on and press again off function The wah wah Tremulant Microphone speed volume Phase shift oscillator Tr3 Microphone Microphone
20. ridge Pair of Dorchester Londspeaker units Special Tota Price 473 Gns 57 Or Dep 6 und 9 monthly paywents 26 11 5 Total 56 2 9 Goldring CS80 Ceramic P U Cartridge 53 Transp plastic cover 3 grs extra Pair of Dorchester Loudspeaker Units ens i a UN OCUN VENE MMC J oc i 4 DF fa AUDIOTRINE HIGH FIDELITY eue t TIBIEI Or Dep 10 0 3 and 9 mthly payments 5 15 5 Total 59 gna Transparent plastic cover 3 gns extra TERMS AVAILABLE ALL PACKAGE OFFERS LINEAR L10 HIGH FIDELITY 10W AMPLIFIER 10 Gns with separate Pre amp Magnetic P U matching To clear EXTREMELY ATTRACTIVE PLINTHS finished in Teak or Afrormosia veneer fraus plastic cover RECORD PLAYING UNITS Money saving units Mounted on Piinth Supplied with trans parent plastic cover Ready to LOUDSPEAKERS na construction Latest high efficiency ceramic magnets Treated Cone sur round D indicates Tweeter Cone providing extended frequency range up to 15 000 c p s L indicates Roll Rubber cone surround linpedance 3 or ld ohms Please state choice Exceptional PE Eure cui aM pg mt Amplifier or Tape R S C TAI2 MKIII 6 5 6 5 WATT STEREO AMPLIFIER HF800D 8 8W 54 3 HF120 12 15 79 29 Garrard SP25 Mk II FULLY TEANSISTORISED SOLID STATE CONSTRUCTION HIGH HEiO2D 10 iow 57 11 HFIZ0D 1s isw avo RPZC Ce Seo ee ble FIDELITY OUTPUT OF 6 5 WATTS PER CHANNEL HFi00D 10 16W 4 19 9 HF126 12 15W 5 5
21. 4 0 D P D T 5 9 8 P D T centre off 5 MEDIUM RANGE ELECTROLYTICS Axial leads 50 50 9 100 25 9 100 50 2 6 250 25 2 6 330 25 9 6 250 50 3 0 500 25 3 9 500 50 4 6 1000 25 4 1000 50 8 2000 25 6 8 DeC s put an end to birdsnesting Components just plug in Saves valuable time Use componenta again and again S DeC only 30 Compact T DeC increased capacity may be temperature cycled T DeC only 50 post free Full range stocked ELECTROVALUE SMALL ELECTROLYTICS Axial leads 4 7 10 4 7 25 5 50 1 ea 10 10 10 25 10 50 33 10 50 10 1 ea 22 25 25 50 47 25 100 10 220 10 1 8 ea Dept PW 8 28 ST JUDES ROAD ENGLEFIELD GREEN EGHAM SURREY Hours 9 5 30 Sat 1 p m Tel Egham 5533 STD 0784 3 Telex 264475 400 TR ANSISTORS etc i OC 7i8 OCs 2 6 OC2R 8 8 OC81D 9 3 AC107 8 OAS 1 8 OCR5 9 OC8S2D 2 6 AC126 2 3 OA 1 8 OC44 2 9 0C140 5j AFILb 9 OALO 1 6 OC45 2 8 OC169 3 6 AF116 3 OAAT 1 9 OC70 2 3 O0C170 4 AF1I7 4j OAB 1 6 OC7 2 3 OCITI 2 3 BFYX18 4 8 QAR5 1 8 0c 2 3 0C202 4 6 BFYS 4j OC 3 8 8 0073 2 3 TK22C 1 8 GETIIS3 2j8 OC 5 i 0C75 2 3 General purpose 1 6 WITH 4 LEAD SIX AMP SERIES THYRISTORS BYZ13 300 PIV 4 B YZI2 600 PIY 5 BY211 900 PIV 6 BYZ10 1200 PIV 74 5 AMP SERIES 100 PIV 7 6 200 PIV 9 300 PIY 10 6 400 PIV 12 800 PIV 25 10 AMP SERIES 50 PLV 10 100 PIV 12
22. OF 12 6 PER PAIR ZN2080 NPN SIL DUAL OUR PRICE 12 6 EACH U23 30 Madt s like MAT Series PNP Transistors 10 ONJUNCTION TRANS CODE D1699 Sil trans FULL RANGE OF U24 20 Germanium l amp Rectifiers GJM up to 300 PIV 10 UT46 Eqvt 2N2646 TEXAS Our price 5 ea Pa for vem Da ug 5 U25 25 300Mc s NPN Silicon Transistors 2N708 BSY27 19 Eavt an EE 190VCB NIXIE DRIVER Metal o 18V 400mV DO 7 Case U26 30 Fast Switching Silicon Diodes like EN914 Micro min 10 25 99 ae 100 UP 4 TRANSISTOR Sim 8 E 2 6 es 1 5W T op Hat U28 Experimenters Assortment of Integrated Circuits un BSX21 amp C407 2N1893 qayt 3 8 ea 10W 80 10 tested Gates Flip Flops Registers etc 8 Assorted Pieces 20 NPN Silicon PLANAR Lm TEATED GE AE A j E dex m fully U29 10 1 amp SCR s TO 5 can up to 600 PIV CR81 25 600 20 RAET MET 2j DS se 24 n ep SET IST E TT IE e pb MEET DS AYMI f s 8 6 each TOS NPN Qty Y marked State voltage U31 20 Sil Planar NPN trans low noise Amp 2N3707 10 1 Go E a dafs an Fully 25 up 3 each d required U32 25 Zener diodes 400mW D07 case mixed Volts 3 18 10 tested and coded TO 18 BRAND NEW TEXAS U33 15 Plastic case 1 amp Silicon Rectifiers 1N4000 series 10 case MULLARD LC AMPLIFIERS GERM TRANSISTORS U34 30 Sil PNP alloy trans TO 5 BCY26 28302 4 10 1 NPNDIFFUSEDSILICON TAA243 O tional amplifier 70 each Coded and
23. XXNXXXX A MARSHALL amp SON 28 CRICKLEWOOD BROADWAY LONDON N W 2 TELEX 21492 Post amp Packing 01 452 0161 2 3 U K only 1 6 CALLERS WELCOME Europe 5 Commonwealth Air 13 TMK METER KITS portunity of building a really fiss These meler kits by TMK offer the unique op g in cost The cabinet is supplied class precision multimeter at a worthwhile Savin with the meter scale and movement and the range selector in position T highest quality components and 194 tolerance resistors are used throughout Supplied complete with full constructional circuit and operating instructions MODEL 200 20 000 O P V Multimeter Features 24 measurement Large 3 2in meter Full ranges with mirror scale scale accuracy DCV and current X294 ACV 3 resistance 3 Special 0 6V DC range for transistor circuit measurements SPECIFICATION 7 e DCV 0 0 6 6 30 120 600 1 200V at 20K OPV ACV 0 6 30 120 600 1 200V at 10K OPV e DC urrent 0 6 0 6 600mA O Resistance 0 10 K 100K 1M 10M ohms 58 580 5 8K 58K at mid scale 6 Capacitance 0 002 0 2uF AC 6V range Decibels 20 to 63dB Output 0 05uF blocking capacitor Uses two 1 5V U7 type batteries Black bakelite cabinet Size 54 32 1 in Complete with test leads KIT PRICE ONLY 92 KIT 3in tweeter uses new Wharte dale Acoustiprene dome diaphragm Crossover unit crossover freq 1 750Hz ALL accessories acoustic
24. screw hole in base 15 8 DISAPPEARING with swivel aud sliding threaded socket fixing nut on bottorn section 8 xection 54 203 3 dia 12 6 0 10 aection 73 563 3 dia 15 9 All are strongly plated P P amp 1 on all above up to three 1 SWITCHES Standard toggle metal 200V 2A One hole fixing SPST 2 3 SPDT 2 9 DPST 3j DPDT 3 3 Slide type Sub min DPDT 1 6 each Smali DPDT 3 way centre off 1 9 Reed magnetic on off 1 9 up to three 1 ld each all additional Rotary Switches etc in list VIBRATORS Famous makes only 12 volt 4 pin non synch 4 8 12 volt 7 pin synch 12 6 1 each either type No other types available MAINS NEON TESTER Fly leads 2 Pocket serewdriver type 3 6 PLUGS Std Jack plastic body 2 8 Screened 3 VALVE HOLDERS B7G or B9A 6d all above 1 up to three Many wore British and Continental standard and miniature PLUGS amp SOCKETS detailed in list Also STANDARD AND SURPLUS VOLUME CONTROLS CONNECTING WIRE 5 coils asstil coils each 5 yds Solid Core 2 9 Flexible 3 8 Super thin for transistor wiring etc 8 8 1 all types per coils PICK UP WIRE Twin Super thin Flex Sereened Sheathed 1 8 yd 6d up to 6 ydr over 6 yds post free TWIN MIKE CABLE 1 3 yd SINGLE MIKE CABLE 8d yd Both flexible screened and sheathed Up to 3 yds 8d each additional yard id extra R F FIELD INDICATOR 5 band with antenna monitoring crystal earpiece visible indieator etc 48 6 1
25. 130 0 19 19 10 10 15 15 23 o0000000000000000000000000000000 99090000000000000006 000020 0a 0900900 54 0 0 3 All goods are in manufacturer s sealed cartons and are insured against loss or damage in transit Guaranteed by return service Carriage 0 for speakers amp stereo tape recorders 7 6 for amplifiers tuners playing decks tape decks 5 for cartridges headphones and transcription arms Send cash cheque with order Personal callers very welcome 9 30 am 6 pm Monday to Saturday Thursday day closing Wolverhampton Staffs Tel Wolv 29246 26 Victoria Street 343 Rr PME PRACTICAL Jo gro t lg SETIN N a new 4 way method of mastering ELECTRONICS by doing ang Seeing BUILD READ and 2 and USE 3 852 DRAW and a modern and profes UNDERSTAND sional CATHODE RAY CIRCUIT DIAGRAMS OSCILLOSCOPE 1 OWN and ssi HANDLE a complete range of present day ELECTRONIC PARTS and COMPONENTS CARRY OUT OVER 40 EXPERIMENTS ON BASIC ELECTRONIC CIRCUITS AND SEE HOW THEY WORK INCLUDING Jum interese VALVE EXPERIMENTS PHOTO ELECTRIC CIRCUIT O A C EXPERIMENTS TRANSISTOR EXPERIMENTS COMPUTER CIRCUIT D C EXPERIMENTS AMPLIFIERS BASIC RADIO RECEIVER e SIMPLE COUNTER OSCILLATORS ELECTRONIC SWITCH TIME DELAY CIRCUIT SIGNAL TRACER SIMPLE TRANSMITTER O SERVICING PROCEDURES This
26. 21 5 28 19 29 19 38 19 3 8 32 19 16 19 24 19 27 4 54 O 59 19 99 19 32 19 40 19 39 OF MAaAFHAOCSOWHMHOSH SH SHOCOSCHBSARKaEROORA Customers are welcome to calf personally Rec Retail Comet Price Price LOWTHER Acousta with PM7 53 0 0 45 19 QUAD EIE DC 66 0 0 52 19 PHILIPS RH 481 11 00 8 2 PHILIPS RH 482 18 0 0 14 19 WHARFEDALE Spgnhnr sy Alredale 69 10 O 57 14 Denton i4 19 0 O 14 19 Super Ligton 22 10 O 18 10 Melton 5 29 10 0 22 19 Dovedale 3 39 10 O 29 19 Rosedale 59 10 0 48 19 WHARFEDALE UNIT 3 Speaker Kit E 11 19 6 9 19 WHARFEDALE UNIT 4 Speaker Kit g 16 0 0 13 10 WHARFEDALE UNIT 5 Speaker Kit T 23 10 0 19 19 CHASSIS SPEAKERS GOODMANS Axiette 8 7 2 GOODMANS Twlnaxiette 8 8 0 GOODMANS Axlom 10 8 8 GOODMANS Axlom 201 12 10 GOODMANS Axiom 301 17 18 GOODMANS Audiom 51 11 6 GOODMANS Audiom 61 16 7 GOODMANS Audiom 81 27 12 GOODMANS Audlom 91 31 5 GOODMANS Audiom 91 100 34 17 GOODMANS ARU 180 3 17 GOODMANS ARU 280 3 17 GOODMANS ARU 480 5 8 GOODMANS ARU 172 3 17 GOODMANS Trebax 100 7 9 GOODMANS Trebax 5K 20KL 8 8 GOODMANS Midax 11 4 GOODMANS Attenuator 3 1 GOODMANS Crossover Networks X0 950 5000 8 B GOODMANS Crossover Networks X0 950 A 6 7 GOODMANS Crossover Networks X0 5000 s 2 6 WHARFEDALE 8 Inch Bronze RS DD 4 8 AE Super 8 RS D 7 12 WHARFEDALE
27. 40 MC1303 52 6 48 45 MC130455 50 47 6 PA246 52 6 48 45 2N3055 15 Mullard 11 5watt 5ilicon Power 25 13 100 11 2N2926 2 NPN Planar All Colours 25 1 8 100 1 6 AF139 6 Siemens V H F 25 5 3 100 4 6 500 3 9 ADI6I ADI62 13 pair Muilard NPN PNP 25 10 pr 100 8 6 pr BY127 4 Mullard 1000v amp Plastic 25 3 3 BT102 500R 12 6 Mullard Thyristor 100 10 3 oras SILICON Diodes 25 1 6 100 1 3 500 1 1 500 4 3 oc4s 3 6 Mullard 25 3 100 2 6 500 2 0C75 500 3 OC20 Mullard 100v 500 13 3 IN4004 5 3j 400 600v E amp 25 2 6 100 2 500 1 10 19 6 2N3819 7j Texas F E T 25 6j 100 5 3 500 4 9 2N2646 10 6 Motorola Unijunction 25 8j 100 7 6 500 6 9 AFI86 9 Muilard V H F 25 500 6 BY 126 3 6 Mullard 800v amp Plastic 25 2 9 100 2 6 BYZI3 4 Mullard 6a 200v 25 3 6 100 3 2 500 2 10 BCI07 8 9 2 9 ea 1 7 7 Planars 25 2 5 100 2 500 1 10 OCP71 19 6 Mullard Photo 25 17 3 100 14 9 500 13 6 500 1 9 BCY34 Mullard 25 5 100 4 3 500 4j 500 1 4 ZENER DIODES 400 MW 5 BZY88 Range All Voltages 3 3 33v 4j 25 INTERNATIONAL 6 BF180 7 6 0CI71 IN4006 7 4 2 6 7 6 0C200 800 1000v J amp 100 2 J I 6 0C201 25 3 4 500 1 9 CORRESPONDENCE SCHOOLS 88 5 0202 100 3 OE TALA 2851
28. 5 6 OC203 6 8 2N3704 BCY30 7 OC204 85 TOTTENHAM COURT ROAD Open all day Saturday Have you had your copy of Engineering Opportunities The new edition of ENGINEERING OPPOR TUNITIES is now available without charge to all who are anxious for a worthwhile post in Engineering Frank informative and completely 1 up to date the new ENGINEERING OPPOR TUNITIES should be in the hands of every person engaged in any branch of the Engineering industry irrespective of age experience or training On SATISFACTION or REFUND of FEE terms This remarkable book gives details of examinations and courses in every branch of Engineering Building etc outlines the openings available and describes our Special Appointments Department WHICH OF THESE IS YOUR PET SUBJECT THIS BOOK TELLS YOU A to get a better paid more interesting job X HOW to qualify for rapid promotion X HOW to put some letters after your name and become a key man quickly and easily X HOW to benefit from our free Advisory and Appointment Depts i x HOW you can take advan
29. 6BZ6 6 G8Q7GT 7 6 128C7 5 35D5 12 6 ATP4 2 3 1L4 2 6 amp C6 3 9 6GU4GT 12 128G7 4 6 35L6GT 8 6 AZI 8 1LD5 6 6C9 14 6 6U7G 10 6 128H7 3 35W4 4 6 4231 9 6 1LN5 8 6CD6G 23 j 6V6G 2 6 128J7 4 6 3523 10 AZ41 10 6 INSGT 7 0 6CH 7 6V6UT 6 6 128K7 4 8 35Z44T 4 9 n6 8 6 1R5 5 6 6CLG6 8 6 6X4 4 3 128Q7G T8 35Z6G T 6 CL33 18 6 184 4 9 6CW4 12 6X5GT 5 14H7 9 6 50hb 7 CV6 10 6 185 4 3 6D3 7 6 6Y6Q S 1487 15 50C5 6 3 CYlC 10 8 1U4 5 9 6D6G 38 6Y7 19 6 19AQ 4 9 50CD6C43 8 CY31 7 6 2p21 6 6 6F1 12 6 7R6 10 8 19H 40 50L6GT 9 D63 5 3A4 4 6F6 19 6 7 B7 7j 90DL 13 7 6 6 D77 2 8 3Ab 10 6F6C 5 7C6 8 20D4 20 b 55Av 8 6 DAC32 7 3B7 5 6F12 3 3 7FK 19 6 20F2 14 85A3 Bj DAF91 4 3 3D6 3 9 6F13 3 6 7H7 5 6 20L 20 904G 87 8 DAFO96 6 6 3Q4 7 6 6F1I5 10 7R7 18 0Pl 17 6 90AV 67 6 DCC90 10 3Q5GT 6 6FI8 7 8 7V7 5 20P3 18 90CG 34 DD4 10 6 384 5 9 6F23 14 2 ohwo 7 20P4 18 6 90CV 38 6 DF35 7 8 3V i 6 2 6F24 13 6 9D7 15 6 20P5 20 90C1 10 DF9i 2 9 5R4GY 10 6 6F25 13 10C 525 25A66 5 9 150B9 14 6 Dr96 8 6 5U4G 5 6 6F28 14 1002 10 20L6 5 6 150 gt 5 9 DF97 10 5V4G 7 6 6F3 8 i0D1 8 j 25Y5 8 30L 20 DH63 8 5Y3GT 5 6 6H6GT 3 10b9 14 7 s5Y55 8 6 302 16 6 DH76 5 523 9 6JbG 3 9 10FL 15 25Z46 6 208 15 DH77 4j 5240 X 7 j 6J6 3 10F4 9 28Z5 8 305 16 6 DH81 10 8 6 30LY
30. ACY18 7 6 ACY19 6 ACY20 4 6 ACY21 5 6 ACY22 B ACY28 6 ACY34 5 ACY 36 4 6 ACY 39 4 6 ACY40 5 AD140 8 6 AD140 1 6 AD161 2 6 AD162 12 6 AF109 3 AF114 4 8 AF115 4 6 AF116 7 6 AF117 4 AF118 5 AF124 8 AF139 4 0 A F178 17 6 ARY927 15 A8Y28 25 ABY29 10 6 A8Y67 8 6 A8Z2 10 AU 10 4 B3M 2 6 BAITO 7 8 BAX3L 5 BC107 12 6 BC108 15 BC109 3 6 RC113 8 6 BC116 4 BC118 3 6 BC134 4 BC135 3 8 BC136 3 BC137 3 6 BC138 10 BCY30 12 6 BCY 31 2 6 BCY 3 8 BCY33 19 6 BCY 34 17 6 BCY38 5 6 BCY39 13 6 BF152 10 BF194 10 6 BF195 9 6 BD124 BrY La 2 6 BSX20 2 B8X 91 5 B8X 76 5 8 BSY91 12 6 BBY 8 5 BSY29 3 B8Y50 B8Y53 4 i B8 Y 66 5 B8Y67 5 BBY95A 6 BSY95 6 BY100 4 BY103 4 86 BYZ10 3 8 BYZ11 3 6 BYZ12 4J BYZ13 5j BY 215 9 6 BYZ16 3 GET102 11 GET103 19 6 MPF102 7 6 MPF103 7 6 MPF104 15 MPF105 6 6 0A5 6 OA7 6 6 OA9 5 OA10 12 6 0447 6 8 OA202 7 6 0A 10 6 6 0A21L 6 OAZ 25 9 6 0AZ228 8 6 0A Z229 19 6 0AZ231 19 6 042234 7 d 0AZ238 A 9 OC16 OC19 2 91020 3 0C2 8 OC23 8 0C24 9 6 BEN3000 5 OC84 14 BF115 925 BF 154 20 BF158 15 BF159 12 6 BF 163 25 BF167 9 BF173 5 0CI22 8 OC123 6 0C139 12 0C140 8 OCI41 5 10C169 8 0CL70 CIRCUITS Type UL9I4 UL923 12 25 100 500 9 9 9 8 7 3 6 6 12 6 11 9 11 SL403A 42 6 41
31. All other Sinclair prodnets in stock 2 000 amplitier 23 Carr 7 6 Neoteric amplifier 48 Carr 7 6 SOLID STATE VARIABLE A C VOUTABE REGULATORS Compact and panel mounting Ideal for eon trol of lamps drills electrical appliances etc Input 230 240v A C Output continuously variable from 20y 230 v Model MR 2305 5 amp 68 x 46 x 43mm 28 7 6 Model MR 2310 10 amp 90 x 68 x 60mm 211 19 6 Postage 2 t TEI Ti1 DECADE RESISTANCE ATTENUATOR Variable range 0 3110 B Connections Unhaloced T and Bridge T Impedance UU 4 range 0 108 10 dB x 10 10 20 30 40dK Freuneney d c to 200kHz 3dB Accur acy 05dB Inidieation dB x 0 01 Maximum input less than 4W 50V Built in 00 2 load resistance with internal external witch Brand new 227 10 0 P amp P 5 RECORDING HEADS COSMOCORD i track heads High imn record playback 65 Low imp erase 20 MARRIOTT 4i track heads High imp record playback 65 Low imp erase 20 Post extra AMERICAN TAPE l irst grade quality Atueric o tapes Brand tion 0 6 3 15 60 300 1 200 Ii 4 d c 0 6 30 120 600 1 200 15 X1 new Discount on quantities A C 0 30uA 611A 60mA ER din 225ft L P acetate 3 6 300mA 500mA Of 8K 8OK jii 6OO0ft DP NAE sus p mem 10 800K B meg 20 to 63 dh mn n00ft std plastic 0 8 6 25 19 6 P P 3 in 900ft L P acetate 10j
32. KENT BR2 7HP Please send me WITHOUT OBLIGATION TO PURCHASE one of the above sets on 7 DAYS FREE TRIAL I will either return set carriage paid in good condition within 7 days or send the following amounts BASIC ELECTRICITY 75 Cash Price or Down Payment of 20 followed by 3 fortnightly payments of 20 each BASIC ELECTRONICS 90 Cash Price or Down Payment of 20 followed by 4 fortnightly payments of 20 each This offer applies to UNITED KINGDOM ONLY Overseas customers cash with order prices as above Tick Set required Only one set allowed on free trial BASIC ELECTRICITY BASIC ELECTRONICS Prices include Postage and Packing This carefully planned series of manuals has proved a valuable course in training technicians in Electricity Electronics Radio and Telecommunications WHAT READERS SAY _ played an important part These Manuals have played an important part in my career K W West Drayton a sound basis These books create a sound basis on which to build a successful future R G Lowestoft Well set out l am well pleased with the series Everything is well set out in self explanatory diagrams D D West Ham A TECH PRESS PUBLICATION B FULL POSTAL ADDRESS Signature E Sis mo c EN EM ae po A E NE NN UB UN UR ERE RR Z POST WOW FOR THIS OFFER 334 BI PAK SEMICONDUCTORS SUPER PAKS Unequalied Value and Quality Satisfactio
33. KGC 397 Wilkes Barrie KIF 650 Birmingham Ala 35 58 KIE 953 Atlanta Ga 35 58 During good conditions in the winter of 1969 stations as far west as KKI 445 Houston and KKM 248 Oklahoma City both on 35 58MHz were heard Usually reception is easiest from the east coast and especially down to KIY 508 Orlando Fla One rare pager only heard twice here is WWA 335 San Juan P Rico on 35 22MHz The aerial in use for these various signals in the lower v h f band has been a vertical 12 foot whip Activity in the west is usually from 1300 1800 b s t The Worldwide TV FM DX Association often publishes articles and lists on activity within the 30 40MHz spectrum in addition io their normal coverage of t v and f m DX proper Information on this club may be obtained from W TV FM DX Assoc P O Box 5001 Harbor Sta Milwaukee Wis 53204 U S A For a sample bulletin enclose 2 IRC Jt should be pointed out that reception upon these high frequencies of ionospheric signals is dependent on sunspot activity other than sporadic E Conse quently there may be periods during which little or no activity is heard However conditions can improve over the space of a few days During January 1970 the highest frequency noted was 39 8MHz after which conditions deteriorated It must be stressed at this point that NO ATTEMPT MUST BE MADE TO VIEW THE SUN DIRECTLY to observe sunspot activity One second is sufficient to damage the eye A telescope
34. London W C 1 R S C COLUMN SPEAKERS covered in Rexine and Vynair ideal for vocalists and Public Address 15 chm matching TYPE CABS 25 80 WATTS Fitted R S C MAINS TRANSFORMERS four 8in hizh flux 8 watt speakers FULLY GUARANTEED Interleaved and Im Overall size approx 48 x 10 x Sin pregnated Primaries 200 250v 50c s Screened l 6 Gns MIDGET CLAMPED TYPE 2 x x 1in e Carr 10j 200v onia GBT Da ee aoe 17 11 Or deposit 3 and 9 monthly 290 0 200v GOMA 6 3v Za 18 11 paymenta 35 8 Total 18 19 6 FULLY SHROUDED UPRIGHT MOUNTING UAE T piua 6 3v 2a 0 5 6 3v 2a 24 9 TYPE C4I2S 50 WATTS Fitted four 12in 220 0 250v Ue orate el aa aah i a d 300 0 300v 100mA 6 3v 42 0 5 6 3v 3a 39 9 11 000 line 15 watt speakers Overall size 300 0 300v 1a0mA 6 3v 4a t 6 97 la RSC ME FI CENTRES LTD CENTRES LTD 56 x 14 x Qin approx Carr For Mullard 510 Amplifier 47 11 26 Gns l 350 0 350v 100mA 6 3v 4a 0 0 6 3v 3a 39 9 Or Deposit 4 and 9 350 0 350v 150mA 6 3v da 0 5 6 3v Ja 47 9 425 0 425v 200mA 6 3v 4a C t ov 3a monthly payments of 58 8 Total 30 8 0 423 0 420c 300m 63v ES aay 3a ov ome HIGH QUALITY Emm i900 duiv 250m 4 3v d C Sv 3a 99 9 LOUDSPEAKERS TOP SHROUDED DBOP THRO TYPE 50 0 2507 TOMA 6 3v 2a 0 5 6 3v 2a 23 9 In Teak ot Afrormosia veneered Cabinets 250 0
35. PZ5 79 6 2 of Z30 stereo 60 PZ5 usually 23 10 or with PZ6 in place of PZ5 21 19 TEST EQUIPMENT FOR YOUR HOME AFIOS SOk v multimeter illus price 8 10 p p 3 6 leather case 28 6 200H 20k v multimeter price 3 17 6 p p 3 case 12 6 TE20D RF Generator illus price 15 p p 7 6 1 TE22D Matching Audio Generator price 17 p p 7 6 TE65 Valve Voltmeter price 17 10 0 Full details and range in catalogue complete SLIM POCKET TEST GEAR O SIGNAL INJECTOR 35 p p 1 6 SIGNAL TRACER 29 6 p p 1 6 most decks Recommended Price 79 6 p p 2 6 Stock List No 16 17 FREE on request BEST VALUE IN U K Choose from 100 complete stereo systems Complete range of individual units also in stock Demonstrations all day 100 STEREO SYSTEMS LOW CASH AND CREDIT HP PRICES Credit terms from 30 purchase callers only HENRY S RADIO LTD WORLD S LOWEST COST STEREO MAGNETIC N EW CARTRIDGE O P 7mV 20 c s 20 Kc s Diamond Stylus Fits O ELECTRONIC ORGANS PUBLIC ADDRESS AUDIO AND TEST GEAR DISCOTHEQUE EQUIPMENT 309 EDGWARE ROAD LONDON W 2 TEL 01 723 6963 l OPEN MONDAY TO SATURDAY 9AM TO GPM THURS 9AM TO 1PM OPEN ALL DAY SATURDAY X COMPONENTS TEST GEAR O HIGH FIDELITY SALES AND DEMONSTRATIONS 354 EDGWARE ROAD LONDON W 2 TEL 01 402 5854 HENRY S LATEST CATALOGUE New print Now
36. ZTX503 5j into 5 to 80 Kit 19 7 6 nett built 24 16 8 nett 2N3702 3 6 40362 18 BC108 2 8 BFX85 8 3 ZTX504 19 Suitable 81 wide range soeakers available 18 15 2N3703 3 3 40406 16 3 BC109 2 9 BFX87 8 8 each nett TE 2N3704 3 9 40408 14 6 BC125 12 BFX88 8 9 ZTX530 5 5 2N3705 3 5 40430 37 BC126 12 BFY50 4 6 ZTX531 8 9 MAINLINE AMPLIFIER KITS RCA SGS designed main amplifier kits Input censitivity 500 700mY for full output into 8 RESISTORS Code Power Tolerance Range Values liob 10 to 99 100 up Power Kit price Suitable unreg available see note below including power supply C 1 20W 5 82 N 220K Q E12 18 16 15 componenta klt C 1 8W 595 4 7 0 330K N E24 2 5 2 1 75 168 nett C Law 10 4 7 Q 10M Q E12 2 5 2 1 75 190 nett C l 2W 59 4 7 Q 10M Q E924 3 2 5 2 95 210 nett f C IW 10 4 7 O 10M OQ E12 6 5 4 5 252 nett _ 138 10 WS n lo 0220 390 E12 Paga am quantit ww 1W 10 1 20 0 22 Q 3 9 quantities Www SW o 19 Q 10K Q E12 15d all quantities 30 WATT BAI LEY A M P PARTS Www TW 5 12 0 10K 2 E12 18d all quantities Special summer reduction to Sept 30th 1970 only Codes C carbon film high stability low noise Prices are in pence each for same ohmic value and power Sensitivity 1 2V for full output into 80 Transistors for one channel 27 5 8 list 6 only nett Transistors for two channels 14 11 list 1 I only nett pM and resistors metal oxide 30 per cha
37. 1 UMR uus 6P25 68A7 68A7GT 68C7 S8C7GT 68G7 6837 63J7GT 08K7 68L7GT 1lE2 12AT6 12AT7 12AU7 12AV6 12AX7 12BA6 12BE6 12BH7 12C8 12E1 12K5 I3K7GT 6 9 12K8GT 12Q7GT 128G7 1487 uaranteed brand 9 tee 11 19 05 7 9 2051 10 7 19G3 70 15933 22 6 6 8 19G6 20 16057 10 13 19H4 85 16060 7 8 5 20P4 17 5084 7j 8 20L6GT 7 8 6065 13 7 8 30C15 15 6080 27 8 6 6 80C17 16 6146 28 7 30C18 15 8020 35 6 6 30F5 18 8 9001 3 6 30FL1 15 9002 4 6 7 9 30FL12 18 6 9003 10 3 6 ovis 10 204 2 6 3 6 3 30115 175 9009 2 6 4 9 30L17 17 C R Tubes 5 130P12 18 VCR97 32 6 5 6 30P19 14 VCR517 50 ll 30PL1 13 VCR517B55 14 30PL13 18 VCR517C45 5 30PLl4 17 5FP7 26 7 7 35L6GT 9 6 88D 180 14 6 35 W4 5 88J 80 Sig 35Z4T ER 88L 80 42 eor dc Ebo THR 7 6 50CD6G 30 80 50EH5 12 931A_ 62 8 M do oi Spacia us 4 CV1031 x SB oq eel PER TER j 6 805 180 K301 4 3 0813 Belaan ili K30 5 6 832A 55 K 337 12 17 866A 15 KRN2A 70 10 954 4 6 WL417A 80 yelas anos o 5 6 957 6 15C22 15 7 991 6 714AY 4 15 1622 17 725A 210 ALL OVERSEAS ENQUIRIES AND ORDERS Please address to Colomor Electronics Ltd 170 GOLDHAWK ROAD LONDON W12 Tel 01 743 0899 2 NEW RANGE U H F TV AERIALS All U H F aerials new fitted with tilting bracket and 4 element grid reflectors
38. 1 6 deductible from first order guaranteed AUDIO EFFECTS 5 SHAW LANE HALIFAX YORKS Buy with confidence and obtain the right results Refunds without question if any of our products fail to give 100 satisfaction AMATEUR BANDS ALL TRANSISTOR SUPERHET RECEIVER KIT No fuss no drilling Just fit the components on our printed circuit Slow Motion tuning Simple IF alignment Perspex front panel Push pull AF amp drives your 8 15 ohm speaker Amp can be used seperately Designed to accept a BFO signal Uses Denco plug in coils 2T 0 5 to 1 54 Mhz 3T 1 67 to 5 3 Mhz 4T 5 0 to 15 Mhz 5T 10 5 to 31 5 Mhz Range 3T normally supplied with kit Uses 9 volt battery Easy step by step instructions Complete Kit 8 19 6 plus 5 6 P P amp Ins Extra ranges 12 POWER CONTROLLER Power at your Not merely half wave control but A single variable control gives zero to full power Uses latest 15 amp 3kW triac and special triggering device types of lighting fires motors drills etc Complete with box power sockct cables etc In kit form with casy to follow instructions 6 9 6 Ready built 9 4 6 plus 5 6 P P amp Ins REVERBERATION AMPLIFIER Self con tained transistorised battery operated An entirely different approach to sound reproduc tion Normally sound reproduction from a single Source has a flat one dimensional effect With this unit proper sound delay through reverberation tones are created with a truly third
39. 12 6J7TU 4 9 lO0r14 7 25Z6G 8 6 306 13 DH10t 25 BASG 6 6 6J7GT 6 6 IOLD1110 30CI 6 8 807 11 9 DH107 6AC7 3 6K70i 2 I0P13 13 30C15 13 958 amp 17 11 BAGH 4 6K7UT 4 6 10PI4 20 30C17 16 1821 10 6 Dk32 7 8 6AK5 5 GK8G 4 12A6 12 6 30CIs 14 5763 10 DK40 10 6AK6 6 6L 19 6 12AC6 7 86 30F5 16 6060 5 6 DK9 5 6 6AL5 2 8 8L6GT 7 9 I2ADG6 7 6 30FLI 13 8 7143 10 86 DK99 9j 6AM6 39 8 6L7GT 12 124E6 12 6 s0FL2 15 7475 14 DK96 7 6AQ5 5 6 6L18 8 l2ATG 4 6 30pL1216 Al83 20 DL33 6j GARG 20 6LI9 27 6 12AT7 3 9 no tg lag 42134 18 6 DL35 4 9 6AT6 4 6LD 0 9 6 12AU6 4 9 18 A3042 15 DL9 5 9 6AU6 5 6N7GT 6 6 12AU7 4 6 30LI 6 3 ACLUPEN DLU4 5 9 6AV6 X 5 6 6P28 25 12A V6 5 6 30LI6 13 9 19 8 DL96 7 YOUR CAREER in RADIO amp ELECTRONICS Big opportunities and big money await the qualified man in every field of Electronics today both in the U K and throughout the world We offer the finest home study training for all subjects in radio television etc especially for the CITY amp GUILDS EXAMS Technicians Certifi cates the Grad Brit I E R Exam the RADIO AMATEUR S LICENCE P M G Certificates the R T E B Servicing Certificates etc Also courses in Tele vision Transistors Radar Computers Servo mech anisms Mathematics and Practical Transistor Radio course with equipment We have OVER 20 YEARS experience in te
40. 18 Carr 7 6 MARCONI TF142E DISTORTION FACTOR METERS Excellent condition Fully tested 20 Carr 15 LAFAYETTE TE 46 RESISTANCE CAPACITY ANALYSER 2 pF 2000 md gt ohma 200 meg olim Also checks inipedance turns ratio insulation 200 250V AC Brand New 17 10 0 Varr 7 0 YO 2 PORTABLE OSCILLOSCOPE A general purpose low cost econonty oscilloscope for everyday use Y anip Bandwidth 2 CP8 1 MHZ Input imp 2 mezgQ v P F lliuminatei scale 2in tube 115 x 180 gt 230m Weight 81b 220 240 Y a c Suppileis brand new with hand book 22 10 0 Carr 10 ADVANCE TEST EQUIPMENT Brand new and boxed in original sealed cartons J1B AUDIO SIGNAL GENERATOR 15 c s to 50 Kejs Sine wave Output 600 ohms or 5 ohms 30 0 0 YM79 UHF MILLIVOLT METER 100 Ke s to 1 000 Mc s AC 10mV to 3v DC 10 mV to 3v Current 0 01 uA to 0 3 mA Resistance 1 ohm to JO inegohm 125 0 0 TTIS TRANSISTOR TESTER Full range of facilities for testing PNP ar NPN tran siators in Or out of circuit 37 10 0 Carriage 10 per item o HOSIDEN DHO4S 2 WAY STEREO HEADSETS headphone a 9Llin and a Giu tweeter Built In individual level controls 8Q imp v5 18 000c s with cable and stereo plug 5 19 8 P amp P 2 6 Each tains con woofer BELCO DA 20 SOLID STATE DECADE AUDIO OSCILLATOR New high quality port able instrument Sine 1 Hz to 100 KHz Square 20 Hz
41. 195 500 500v D C Current 0 50 uA 0 250 mA HKeslstance 0 60K 1 8 Meg ohm Deci hels 20 to 4 22d B size of meter 4j x 31 x lin Complete with leather case 85 P amp P 3 8 20 000 p p v DC voltage 5 95 50 250 500 2 5 K 20 000 ohms per volt AC voltage 10 50 100 500 1000 volts 10 000 ohms per volt DC Se Current 0 50 uA 0 2 5 mA 0 250 mA Resistance 0 6K U t Ma 300 ohm and 30K at centre scale Capacitance 10f to 001 mtd 001 uf to l uf Decibels 20 to 221B Blize ii x31rlin P amp P 71 qu LIND AIR LA 20 A fantastic stereo amplifier made exclu sively for Lind Air and representa con siderable advance in solid state stereo amplifiers Inputs for gram and radio tuner and provision for direct tape recording Attractive and modern panel with bass treble balance and volume controls also on off and stereo mono switch Output 5W per channel music power Frequency response 40 20 000Hz 8 16 ohm speaker matching Size 164 x 14 x 4 eet a o Rubio SINCLAIR C 10 INTEGRATED CIRCUIT 10 watt Amplifier Bize only 1 x 0 4 x 0 2in A true hi fi amplifier complete with manual giving detalla of a wide range of applications and instructions Guaranteed 9 years ONLY 59 6 P amp P 1 6 SPECIAL TRANBFORMER FOR OPERATING SINCLAIR 1C 10 from A C mains 230 250v Output 13v at 0 5amp 16 6 P amp P 2 6 BRITISH MADE TOP QUALITY J100L J1002 J1003 J1004 J1005
42. 2 8 DIN SOCKETS Chassis 8 pin 1 6 5 pin 8 DIN SOCKETS Lead 8 pin 3 6 5 pin 5 DIN PLUGS 3 pin 8 8 5 pin 5 VALVE HOLDERS 9d CERAMIC 1 CANS 1 E M I 134 x 8in LOUDSPEAKERS With flared tweeter cons end ceramic magnet 10 watts 45 Bass res 45 60 cps Flux 10 000 g amp uss F4 Speech coil 8 or 15 ohm 34M O Also with twin tweeters Complete with crossover 3 or 8 or 15 ohms 10 watt Recommended Teak Cabinet Size 18 x 10 x fin MINI MODULE LOUDSPEAKER KIT i0 WATT 65 CARRIAGE 5 Triplo speaker system combining on ready cnt baffle k in chipboard 15 in x 84 in Separate Bass Middle and Treble loudspeakers and crossover condenser The beavy duty 5 in Bass Woofer unit has 2 low resonance cone The mid Range unit is specially designed to add drive to the middle register and the tweeter recreates the top end of the musical spectrum Total response 20 15 000 cps Full instructions for 8 or 8 ohm TEAK VENEERED BOOKSHELF ENCLOSURE 16 x 10 x 9 in Modern Scandinavian fluted front design for Mini Module 5 Post 5 HI FI STOCKISTS Pusb Pull Ready built with volume control 9v 5 CUSTOMERS FREE CAR PARK 337 WHITEHORSE ROAD CROYDON Open 9 5 p m Wednesdays 9 I p m Saturdays 9 5 p m ALL MODELS BAKER SPEAKERS IN STOCK BAKER 2in MAJOR 9 30 14 500 c p 12in double cone woofer and tweeter cone together with a BAKER ceramic magnet assembly ha
43. 20 CA3043 21 6 CA3013 CA3028A 14 9 C A3044 24 CA3014 CA3028B 21 CA3045 24 6 CA3018 CA3035 24 6 CA3046 15 2 CA3020 CA3036 14 6 CA3048 40 9 CA3021 31 3 CA3039 16 9 CA3051 26 9 Application notes for each individual type 2 6d per copy IC10 Sinclair Audio Amp 59 6 TAA263 Mullard Linear 15 PA234 GE IC 1 Watt Amp 17 6 TAA293 Gen Purp Amp 20 PA237 GE IC 2 Watt Amp 32 6 TAA310 Record Playback Amp PA246 GE IC 5 Watt Amp 52 6 30 PA424 GE iC Zero Voltage TAA320 MOS LF Amplifier 13 Switch 43 TAD100 Mullard IC receiver 45 SL403A Plessy 3 Watt Amp 42 6 3N84 GE Silicon controlled SL702C Plessy Linear 29 6 switch 26 Data sheets 1 SL403A 2 6d IC10 data not sold separately New low integrated circuit prices Fairchild u S A micrologic R T L epoxy case TOS temperature range 15 C to 55 C 1 11 12 24 25 99 100 uL 900 Buffer TOES S T 6 6 5 6 uL 914 Dual 2 input gate 8 7 6 6 5 6 uL 923 J K Flip Flop 10 6 10 9 6 9j Data and circuits article 5 page at 2 6 Article 30 Suggested Circuits for Micrologic at 3 TOS to DIL conversion spreaders adaptors at 1 6 each BC10 x 9 25424 IFAR 25 6 100 33 PIW 1 24 25 99 100 1N4001 50 1 6 1 5 1 4 1N4002 100 2 1 10 1 8 1N4003 200 2 6 24 2 2 1N4004 400 2 9 2 8 2 7 Siemens Telefunken 1N4005 600 3 211 2 9 NPN PNP output pair 1N4006 3 6 25 9 100 8 1N4007 q ADI61 2 10J 2N487 6 9 Motorola unijunction 25 5 9 100
44. 20 6 tin 29 2 in 57 8 lin 16 9 14in 18 6 12in 21 6 Sin 89 lin aq 88 6 TRANSISTOR MAINS POWER PACKS FULL WAVE 9 volt 500mA Size 44 x 24 x Lin Metal cane 49 6 Crackle finish Output terminals On off switch Hait Wave 8 volt 50mA Size 24 x 1tin Snap terminals 32 6 MAINS TRANSFORMERS s 250 0 250 50 mA 6 8 v 2 amps centre tapped 250 0 250 80 mA 8 8 v 4 amp 250 0 250 80 mA 8 3 v 3 5 a 6 3 v 1a or 5 v 2 a 350 0 350 80 mA 6 3 v 3 5 a 6 3 y 1a or 5 v 2 a 800 0 800 v 120 mA 6 3 v 4 a C T 6 3 v 2 a MINIATURE 200 y 90 mA 49 8 v 18 24 x 2x 1fin MIDGET 220 v 45 mA 6 3 v Za Mer HEATER TRANS 6 3v 1j a 10 6 6 3 v amp Ditto tapped sec 1 4 v 2 8 4 5 8 3 v li amp GENERAL PURPOSE LOW VOLTAGE Outputs 8 4 5 6 8 8 10 12 15 18 24 and 30 v at 2 amp 88 lamp 6 8 10 12 18 18 20 24 30 36 40 48 80 88 AUTO TRANSFORMERS 0 115 230 v Input Output 80 w 18 6 150w 38 500w 5 1000w 12 CHARGER TRANSFORMERS Input 200 250v for 8 or 12v 11 amp 24 4 amp 38 FULL WAVE BRIDGE CHARGER RECTIFIERS 8 or 12 v outputs 14 amp 8 2 amp 11 4 amp 17 COAXIAL PLUG 1 3 PANEL SOCKETS p LINE 3 8 OUTLET BOXES SURFACE OR FLUSH BALANCED TWIN FEEDERS 1 yd 80 dm or 300 ohms JACK SOCKET Std open circuit 2 6 closed circuit 4 6 Chrome Lead Socket 7 8 Phono Plugs 1 Phono Socket 1 JACK PLUGS Std Chrome 3 3 5mm Chrome
45. 22 O 17 I9 31 0 0 25 5 82 10 O 70 IO 126 9 3 104 10 181 tl 9 149 10 59 13 IG 50 19 67 3 6 56 19 40 9 0 32 10 68 8 3 59 10 39 0 0 33 0 5 IO O 44 10 61 17 9 52 12 26 14 6 19 15 69 20 82 10 42 0 72 9 0 62 15 104 9 0 89 10 97 13 0 82 10 303 9 0 255 O0 87 16 9 74 IS 98 15 6 85 10 77 14 9 67 10 172 6 5 145 0 212 0 O 177 IO 243 17 I0 207 10 187 10 O I49 10 99 10 0 84 IO 121 17 1 102 10 136 3 1 II2 10 89 IO 0 79 10 129 I O 105 O 148 O 0 i20 O 99 0 0 84 IO 79 10 0 68 0 QOO 0000009000 000020204000000000 o 00000000 990004 O 000004000 OOooo00 0090000000000000000 KEF Concerto LEAK Mini Sandwich PHILIPS RH781 PHILIPS RH69I TELETON CRIOT TELETON F2000 TELETON Mx990 TELETON R8000 TELETON TFSS5O SPEAKERS ARENA HT7 ARENA HTIO ARENA HT20 ARENA HT2I ARENA HT26 ARENA HT27 ARENA HT328 B amp W DMI B amp W DM3 B amp W DM70 CESTION Ditton 10 CESTION Ditton 15 CESTION Ditton 25 DULCI AS3 GOODMANS Maxim GOODMANS Marimba GOODMANS Mezzo II a aa O Magnum GOODMANS Magister GRUNDIG System 300 GRUNDIG System 412 GRUNDIG System 740 KEF Cresta KEF Celeste Mk 2 KEF Concord KEF Concord LEAK Sandwich
46. 250V A C Fully built 2 x UCL82 metal rect ganged vol and tone cont on off balance 11 x 34 x din high Double wound mains trans with supporting brackets For 3 ohm speakers 6 8 p amp p MONO GRAM CHASSIS 3 WATT 3 Wave band long med short Gram 200 250V A C Ferrite aerial Chassis 13 x 7 x bin Dial 13 x din Double wound mains transformer 5 valvee ECHSI EF89 EBC81 EL84 EZ80 Price 10 12 8 7 0 p amp p Output trans for 3 ohm speaker NEW TAPE AMPLIFIER for 4 track B 8 R Deck TD2 Mains and output Trans 10 x 8 x 4 overall Rect ECC83 EL84 Mike and Gram Inputs 7 5 0 10 p amp p For 3 ohm speaker For 200 250V A C GLADSTONE RADIO 66 ELMS ROAD ALDERSHOT Hants 2 mins from Station and Buses FULL GUARANTEE Aldershot 22240 CLOSED WEDNESDAY amp A E for enquiries please 398 en PHOTOELECTRIC KIT CONTENTS 2 P C Chassis Boards Chemicals Etching Manual Infra Red Photo transistor Latching Relay 2 Transistors 3 Diodes Resistors Gain Control Terminal Block Elegant Case Screws etc In fact everything you need to build a Steady Light Photo Switch Counter Burglar Alarm etc Project No 1 which can be modified for modulated light operation oy PHOTOELECTRIC KIT 39 6 Postage and Pack 2 6 UK Commonwealth SURFACE MAIL 3 6 AIR MAIL 1 0 0 Australia New Zealand S Africa Canada and U S A Also Essential Da
47. 30 9 0 24 19 6 TELETON 203E se 28 7 6 1919 6 TRUVOX TSA 200 5412 0 3419 6 VOLTEX 100 watt stereo discotheques electronic ally mixed Inputs 185 0 O 139 6 0 TUNERS ARENA F211 39 10 0 33 19 6 ARMSTRONG 523 AM FM 52 9 0 4419 6 ARMSTRONG 524 FM 40 4 6 3419 6 ARMSTRONG M8 pecoda 9 10 0 719 DULCi FMT 7FM 22 10 1719 6 DULCI FMT 7S Stereo 31 0 0 25 5 6 GOODMANS Stereomax 82 10 5 7119 6 LEAK Stereofetic Chassis 59 18 0 53 19 6 LEAK Stereofetic inteakcase 67 3 6 59 19 6 PHILIPS RH 690 e 39 0 O 3119 6 PIONEER TX500 AM FM 7718 0 63 19 6 PIONEER TX900 AM FM 153 13 10 125 O QUAD Stereo FM 51 0 0 3919 6 ROGERS Ravensbourne 6117 9 49 19 6 ROGERS Ravensbrook 45 0 2 39 19 6 ROGERS Rarepebsook cased a 51 5 3 4219 6 SINCLAIR 2000 X 26 14 6 19 4 6 TRUVOX FM 200 1C 60 1110 3919 6 All above tuners are complete with MPX stereo decoder TUNER AMPLIFIERS ARENA 2400 90 6 O 7119 6 ARENA 2600 Stereo AM FM 111 6 0 94 0 ARENA 2700 Stereo 105 0 0 85 0 0 ARENA T1500F 72 9 0 59 19 6 ARENA T9000 303 9 0 258 0 0 ARMSTRONG 525 8716 9 68 19 6 ARMSTRONG 526 x 98 15 6 79 19 6 ARMSTRONG MB decoder 910 0 719 6 GOODMANS 3000 7714 7 66 19 6 PHILIPS RH781 74 19 6 5419 6 PHILIPS RH790 125 0 0 101 19 6 PHILIPS RH691 7 83 0 0 7010 6 PIONEER KX330 AM EMISW 7812 4 6219 6 PIONEER SX770 AM F
48. 5 AF116 3 6 2N1306 7 AF117 3 6 2N1308 9 AF239 12 6 2N3819 FET AF186 10 2N3844A AF139 10 Power BFY50 4j Transistors BSY25 7 8 0020 10 BSY26 3 0C23 10 BSY27 3 0C25 8 BSY28 3 OC96 5 BSY29 8 0C28 7 6 BS8Y95A 3 OC35 amp QC41 2 06 0C36 7 6 0C44 2 6 AD149 10 QC45 2 8 AUY 10 30 0C71 2 6 2N 3095 15 0C72 2 8 28034 10 OC73 8 6 Diodes 0oC81 2 6 AAY 42 2 OC81D 2 6 OA91 2j OC83 4j 0479 1 9 0C139 2 8 QA81 1 8 0C140 3 6 IN914 1 6 E o et Too Egas Packs of your own choice up g to the value of 10 with orders over 4 RETURN OF THE UNBEATABLE P I PAK NOW GREATER VALUE THAN Full of short lead semiconductors and electronic components approx 170 We guarantee at least 30 really high quality factory marked Transistors PNP and NPN and a host of diodes and rectifiers Mounted on printed circuit panels Identification chart supplied to give some information on the transistors t PI PLEASE ASK FOR PAK P 1 2 P amp P on this Pak LOOK AT THESE PRIGES CARTRIDGES Acos GP67 2 GP91 38C 22 8 Acos GP93 1 29 8 Acos GP94 1 32 0 Sonotone 9TAHC 39 6 All above in makers cartons BSR X4H 30 1 WATT AMPLIFIER Complete with volume control rectifier smoothing ect fully transistorised OUR PRICE 27 8 PLUGS amp SOCKETS Phono plugs red white yellow green grey blue black 11d 9 per doz Coaxial plugs aluminium 1 8 Coaxial couplera 1 2 pi
49. 6 SL72B type 8 10 0 p p 6 GL69 Type 9 15 0 p p 6 6 O Goldring GL69 with plinth and cover and G800 cartridge usually 51 39 10 0 p p 12 6 SCOOP New i TRACK TAPE DECKS British made 3 speed mains operated Fitted Marriott track heads tape machine XRPSI7 and XESII Piano key operation Designed for the home constructor Operates with up to 7 spools vertically or horizontally Size 13 x 10 x Sj PRICE 13 19 6 p p 10 6 ELECTRONIC ORGANS MODERN ALL BRITISH TRANSIS TORISED DESIGNS AVAILABLE AS KITS OR READY BUILT TEAK VENEERED CABINETS FOR ALL MODELS 49 NOTE 61 NOTE SINGLE MANUAL ae ALSO TWO MANUAL 49 KITS AVAILABLE IN SECTIONS AS REQUIRED HP and CREDIT SALE FACILITIES FREE 16 PAGE BROCHURE Covering organs in kit form and ready built write or phone to ORGAN DEPT Ask for Peter Elvins ALL WITHIN 100 YARDS N 303 309 354 356 EDGWARE ROAD LONDON W 2
50. 6 Details in list RETRACTABLE FLEXIBLE LEADS Space saving Curly many uses in car and home with phono plug each end 6ft 4 6 12ft 7 8 With phono plug one end phono socket at other 6ft 5 121t 8 6 1 each all types SPECIAL PURCHASE COMPUTER PANELS clean and unused TYPE A 41 x 4 with eight Mullard OC43 transistors 24 OABL diodex 32 resisters ete 8 8 per panel TYPE B 5 x 4 two Mullard OC43 transistors six OA47 aud four OA91 diodes resisters and other items 5 6 per panel POT CORES type L 2 exactly ax sold elsewhere at 15 P P and 1 ali three iteme 1 up to 3 and pro rata CURRENT LIST With many more items sent if requested with all orders or free for S A E Post free overseas This advertisement cancels all previous ones and lists supplied prior tu July 31st 1970 FELSTEAD ELECTRONICS PW34 LONGLEY LANE GATLEY CHEADLE CHESHIRE SK8 4EE TERMS Cash with order only No C O D or caller service Post packing and insurance charges are shown in brackets after all items Regret orders under 0 plus carriage cannot be accepted and a minimum charge of 1 is now made Charges apply to G B and Eire only Overseas orders welcomed Air or surface mail at cost Sent at buyer s risk unregis tered and uninsured unless specified and min insurance reg fee of 3 2 sent S A KE please or all enquiries otherwise regret cannot be replied to New and unused at 8 6 each If youre atele
51. 6 ECC82 5 9 EL9o 7 OZ4 4 6IPX25 27 6 UBFKO 7 5CPl 55 6BSG 8 6 7C 6 15 19AQ5 5 50Co 6 3 DCC90 20 ECC83 6 8 ELLSO 20 PC86 11 6 PY33 10 9iUBFS8Y 7 6 CV1536 65 6BA6 6 7D5 8 20D1 10 50CD6G 31j DF33 8 ECC8i 5 6 EM34 16 PC88 11 6 PYSI 5 9 UCCRi 8 6 ACR131100 6BE6 7 6 7H5 6 6 20F2 14 50L6GT 8 DE7O 9 ECC8s 5 EMBO 7 6 PC97 8 9 PYR2 5 8 UCCso 7 6 VCR97 45 6BH6 8 7R7 13 20L1 20 7 9 6 DF9 4 ECCB8 7 6 EMBI 12 8 PCCS4 6 6 PY83 7 UCFS0 8 6 VCRDIB 6BJ6 1 9 787 45 20P4 20 78 5 DF92 3 6 ECF80 6 6 EM84 7 6 PCC89 10 6 PY500 18 6 UCH42 10 6 6BQ7A 6 6 7 4 8 6 20P5 20 80 7 6 DF96 7 6 ECF82 6 6 ESU150 20 PCC189 10 6 PY800 8 6 UCH81 7 VCR31 C 6BR7 9BWwe 7 20A6 73 DH77 4 9 ECH21 12 6 EYol 7 6 46 OAIO 3 OC36 3 6 0C77 8 0C122 12 6 Manufacturers and Export Inquiries Welcome TRANSISTORS OA79 1 9 0044 4 OC78 3 OC123 4 4 OA81 1 6 0C45 3 3 10C78D 2 3 0Cl29 7 6 OBSOLETE TYPES A SPECIALITY A ae 6 0 AC128 4 AF118 12 OA91 1 6 0C46 3j 0CT79 5 0C140 8 6 OTATION NY VALVE NOT 2N1305 5 ACI76 6 2 BCl08 3 6 OA200 95 OCo8 12 6 0C8 4 OCl4l 15 3 QU S FOR ANY VA OSIER 2N2147 16 6ACY18 4 BCl09 3 6 0420 2 OC 9 17 OCSID 3 OC169 8 Express postage 9d per valve ENSINA Sl ACY 3l BFY51 8 0AZ242 4 6 OCTO 3 6 OCSIDM 3 OCl70 3 6 3 7 Wo OD OND s aCY2s 4 BFY90 19 6 0AZ246 4 6 0C71 3 OCBIM 25 OCI7 6 Ordinary postage 6d per valve C
52. 6 P amp P pap A G sensitivity relative to 10w output TONE CONTROLS ARE COMMON TO ALL INPUTS Bass Boost 12dB at 60Hz Bass Qui 13dB at 60Hz Treble Boost 11dB at 15 KHz Treble Cut 19dB at 15 KHz With bass and treble controls central 3dB points ate 30 Hz and 20 KHz POWER OUTPUT For speech and music 50 watts rms 100 watts peak For sustained music 45 watta rms 90 watts peak For sinc wave 38 5 watta rms Nearly 80 watts peak Total distortion at rated output 3 2 at 1K Hz Total distortion at 20 watts 0 15 at JK Hz Output to match into 8 or 15 ohms speaker system NEGATIVE FEEDBACK 20d B at IKHz SIGNAL TO NOISE RATIO 60dB MAINS VOLTAGES adjustable from 200 250V A C 50 60Hz A protective fuse js located at the rear of the unit Output impedance 3 8 and 15 ohms CAR RADIO ALL TRANSISTOR Beautifully designed to blend with the interiors of all cars Permeability tuning and long wave loading coils ensure excellent tracking sensi tivity and selectivity on both wave bands R F sensitivity at 1 MHz is better than 8 micro volts Power output into 3 ohm speaker is 3 watts 43in deep Originally sold complete for 15 4 6 SET OF PARTS 6 6 Q ay eye PRI Circult diagram 2 6 Free with parts Speaker baffle and fixing kit 25 extra plus 4 P amp P Postage free when ordered with parts See top of previous page for a
53. 7 6 3N139 AFI7 5 02 Dkoo 76 EF3D 6 POCHO GB OAL OC 4 4 00206 10 3N140 19 0 AP YTD Sei eee DE95 7 6 EF40 10 PCCI89 11 6 0479 1 9 0C45 2 6 IN21 3 6 3N154 19 ASY26 5 6 DLOZ eEFal 18 6 PCEs00 15 OA81 1 6 0C7 3 INSIB 5 3N159 29 ASY28 BIG optog 4 ps dein icum Sole poloen em CORN BAV segi do DM 0 yFs5 6 6 PCF84 9 83 OA210 7 8 OC73 11 IN7O0 4 10Dl 3 BCI08 3 SD91S 53 DM71 7 6 EF86 6 3 PCFS6 10 OA211 9 6 OC75 4 0 IN702 7257 3 28303 10 BCY10 9 sp9 8 6 3 DY86 6 gr89 5 3 PCF200 15 6 OAZ200 11 0C76 5 IN746A 40594 27 8 BCY72 7 9 8D948 6 6 DY87 S 8EF9I 8 PCF201 15 6 OAZ201 10 OCSI 4 series 5 340595 27 0 BFY51 ue 3 DY502 9 0 EF92 7 6 PCF801 9 9 0AZ202to OC8D 3 IN821A 217 40636 2 BPYs2 4 O BD95S q ES8CC Ol EF95 5 PCF802 9 9 0AZ206 8 6 OCSIDM 3 IN823A 98 40968 27 B805 7 8 ZE 7 8 7 EF183 6 6 PCF805 14 8 OAZ207 9 6 0C82 8 IZMT5 7 40869 29 B8l 9 Z R EABC80 ios EF184 7 PCF806 18 OAZ208 to OC82DM 3 IZMTIO 6 9 ACI96 4 6 BS2 9 8 Zener diodes Roo I9 EFL200 15 6 PCF808 14 6 OAZ213 6 8 OC83 4 6e IZT 13 6 ACIo7 4 6 BUIOO 36 3 6 ea EBoss gi EL34 10 6 PCH200 14j 047223 to QC83B S IZTIO 12 9 AC128 8 BYZI3 5 Z2A range EBC 108 Epi 10 6 porez v6 OCiS ls oci l oNixe GO A TS BYZIG 18 ra O ea SEST 26 EL84 4 9 PCL83 13 OC22 8 6 0C139 6 6 2N3053 6 6 AD149 11 CR81 20 Big ENA ea EBF83 8 6 5156 s PCLAS 9 OCO6 E OCIO E 2N3054
54. 8 358 29 41ft AERIALS each consisting of ten Sft iin dia tubular screw in sections 11ft 6 section whip aerial with adaptor to fit the 7in rod insulated base stay plate and stay assemblies pegs reamer hammer etc Absolutely brand new and complete ready to erect In canvas bag 3 9 6 P amp P 10 6 METERS Full List of our very large stock of meters on request H A C SHORT WAVE KITS WORLD WIDE RECEPTION Famous for over 35 years for Short Wave Equip ment of quality H A C were the Orlgina suppliers of Short Wave Receiver Kits for the amateur constructor Over 10 000 satisfied customers including Technical Colleges Hoa pitals Public Schools R A F Army Hams etc IMPROVED 1970 RANGE One valve model DX complete kit pricc 56 6 Postage and packing 3 6 Customer writes Definitely the best one valve S W Kit available at any price America and Australia received clearly at good volume This kit contains all genuine short wave components drilled chassis valve accessorics and full instruc tions Ready to assemble and of courac ag all our products fully guaranteed Full range of other S W kits including the famous model K and K plus iltustrated above Ail orders despatched by return Mail order only Bend now for a descriptive catalogue order form H A C SHORT WAVE PRODUCTS 29 Old Bond Street London W
55. 9 poles 10 6 10 6 14 0 14 6 28 6 22 6 22 6 38 6 38 6 10 poles 10 6 10 6 14 6 18 6 22 6 22 6 22 6 42 6 42 6 kl poles 10 6 14 6 14 6 18 6 26 6 26 6 26 6 46 6 46 6 12 poles 10 0 14 6 14 6 18 6 28 6 26 6 26 6 50 6 50 8 HI FI SPEAKERS 15 30 40 amp 100W FULL FI 12 INCH LOUDSPEAKER This is undoubtedly one of the finest loudspeakers that we have ever offered produced by one of the country s most famous makers It has a die cast metal frame and is strongly recommended for Hi Fi joad and Rhythm Guitar and public address Flux Density 11 000 gauss Total Flux 44 000 Maxwells Power Handling 15 watts R M S Cone Moulded fibre Freg response 30 10 000 c p s Specify 3 or 15 ohms Mains resonance 60 c p s Chassis Diam 12in 12iin over mounting lugs Baffle hole llin Dian Mounting holes 4 holes 2In diam on pitch circle 1 in diam Overall height jtin A 6 speaker offered for only 8 19 6 12jn 40watt 8 19 6 l5in 95 watt 87 19 6 18in 100 wait 19 10 0 plus 7 8 p amp p THIS MONTH S SNIP FRIDGE UNIT Sealed compressor type Bultable for cabinets up to 7 cublc ft We offer the sealed unlt type as fitted to inost of the better fridges Made originally to flt certain Philips and Stella modela the unit comprises a compressor inaulated and sealed in for allent operation a cooling radiator a freezer box and tubing all gassed up ready for operation from our standard 230 940 volt mains We offer these un
56. ADDRESS RENI MM a e p bha ooo V olo tien oe os o a a o P W Block Letters Please J L ERA Es Es ee ES EM ms SaL N radio control work it is often useful to use I a field strength meter it should not be regarded as a superfluous piece of equipment It is a very simple circuit see Fig 1 easy to build and provides a very convenient way of checking that a trans mitter is working correctly Also the field strength meter is handy for comparing the output power of different transmitters THE CIRCUIT Refering to Fig 1 LI and VC1 comprise the tuned circuit The aerial which should be a small telescopic type connects to one side of the tuned circuit The signal is tapped off from the tuned circuit rectified by D1 and smoothed by C1 The voltage appearing across C1 will for most applica tions be enough to give a decent reading on a meter placed across it but for further sensitivity this voltage is made to bias the base of Trl where this is done the meter is of course not required across C1 VRI R1 R2 and Tri form a bridge circuit and before taking any readings should be adjusted for zero current The r f signal after being rectified will bias the transistor causing the bridge to un balance and the meter will show a reading It will quickly be seen that the higher the r f signal the greater will be the unbalance of the circuit and so Telescopic aerial vC1 25pF Di OA70 1
57. C operation M ema no temp 86100 9i amp 2612 6 ts Fink Se carte 0 Complete with probe and Z supplied i instructions gt O Tin SEU 17 10 0 P amp P 6 M in excellent 2 FEL WNT TRIO COMMUNICATION M E r vond tton M AREE RECEIVER MODEL 9R 59DE Additional probes avail 3 fully teste FEN me j 4 a 3 able R F 42 6 H V 50 and check M eU g 4 band receiver covering 550 Ke s to 30 Mc s REC SET SA Tem EOS 1 00 1 lh i nm continuous and electrical eur cue 18 2 COSSOR 1049 DOUBLE 20 eg iY 40 and 80 metres 8 valve plus 7 diode circuit f arias m vain FMT 4 8 obm output and phone jack SSB CW amp ANL p c Hagu OSCILLOSCOPES I DO pe AM Variable BFO 8 meter amp Sep bandspread Do Oeo Ca S pbi de d Coa TYPE 13A DOUBLE BEAM I9 il Ai WOR olei dial TF 455 Kc s O Audio output 1 5 W e r 20 Carr 30 OSCILLOSCOPES Maii inl i MEAS Variable RF and AF gain controls 115 250V regen A C Mains Beautifully designed Size 7 x 15 x AM FM SIGNAL GENERATORS An excellent general pur Vin With instruction manual and service data 42 carriage paid TRIO COMMUNI lt q D5 Epillator reste NO pose D B oscilloscope CATION TYPE HEADPHONES Normally 5 19 6 OUR PRICE 3 15 0 if purchased with BT d seg che T B 2 cps 750 Ke s above reciever precision instru ment made for the Bandwidth 55 Mes ee a Miei VIEM TRIO TS 510 AMATEUR TRANS
58. Dept 168K Aldermaston Court Alder maston Berks MM MM M M Radio Operators There wil be a number oi vacancies in the Composite Signals Organisation for ex perienced Radio Operators in 1971 and in subsequent years Specialist training courses lasting approxi mately nine months according to the trainee s progress are held at intervals Applications are now invited for the course starting in January 1971 During training a salary will be paid on the following scale Age 21 848 per annum 22 906 s 23 943 PP 1 24 981 LN gt 25 and over 1 023 Free accommodation will be provided at the Training School After successful completion of the course operators will be paid on the Grade I scale Age 21 1 023 per annum 22 ra 1 087 or E 23 Zu 50S 4 24 cela 7 ji 25 highest age point 159895 5 then by six annual increases to a maximum of 1 749 per annum Excellent conditions and good prospects of promotion Opportunitles for service abroad Applicants must normally be under 35 years of age at start of training course and must have at least two years operating eX perience Preference given to those who also have GCE or PMG qualifications Interviews will be arranged throughout 1970 ADPlication forms and further RECRUITMENT OFFICER Government Communications Headquarters Oakley Priors Road CHELTENHAM Glos GL52 5AJ Tel No Che
59. E M L Woofers 62 x 64in square 8 onni 59 6 P amp P 4 6 E M Crossover 16 6 P amp P 1 EAGLE Crossover units 3 or 16 ohms 17 4 P amp P 1 6 Bakers 12in 25 watt 15 ohm 6 6 0 P amp P 5 6 VYNAIR Widths from 40 to 54in 15 yd oft roll P amp P 1 9 4 yard 8 P amp P 1 9 Send 1 stamps for samples a ELF An extension speaker of quality 9 x 54 x Skin veneered in natural teak with smart gold and brown Vynair front trimmed with white Fitted re conned Sin 3ohm speaker The baffle is half inch Vds pese bargain at 37 6 P amp P GIEGER COUNTERS LATEST GOVERNMENT RE LEASE OF THESE EXCEEDINGLY POPULAR AND WELL KNOWN CONTAMINATION METERS Which were intended for use should the need arise by the Civil Defeuce etc These are new or virtually as new being shelf stored only and are complete with all parts including Carry ing Haversack Cable and Probe Instructions for use This Model incorporates a plug in Vibrator Power unit instead of the normal Battery Holder thereby using four standard Mallory R M 12 R Long Life Bat teries Not supplied List Price 70 SUPPLIED AS ABOVE IN MAKER S CARTON COM PLETE AND TESTED 90 POST 10 TWO CARRIAGE PAID FEW ONLY NOT BOXED SLIGHTLY SOILED CARRYING CASE ONLY 50 Carr 10 J H TOWNEND 21 THE ROUNDWAY MORLEY NR LEEDS YORKS A CORNUCOPIA OF COMPONENTS Scarce valve selected T V components Spea
60. ECCa5 5 PCC189 9 6 U191 12 ECH35 5 6 PCF80 5 11 U251 14 ECH81 5 9 PCF801 6 6 U329 14 ECL80 6 6 PCF802 8 9 UABC80 6 ECL82 6 8 PCF80512 9 UBC41 8 8 ECL86 7 6 PCL82 6 9 UBF89 6 3 EF39 4 6 PCL83 11 9 UCC85 7 3 EF80 4 6 PCL84 7 UCH81 6 6 EF85 5 9 PCL85 8 6 UCLS2 6 9 EF86 6 3 PCLS6 8 UF41 10 6 EF89 4 9 PFL20011 6 UF89 6 EF183 5 6 PL36 9 8 ULA1 11 9 EF184 6 PLS 9 2 UL84 8 8 EH90 6 PL82 5 9 UY4 7 EL33 9 8 PL83 6 3 UY85 5 8 On 2 valves or more postage 6d per valve extra Any insured parcel against damage in transit 6d extra Office address no callers GERALD BERNARD 83 OSBALDESTON ROAD STOKE NEWINGTON LONDON N 16 BUY THIS BEST SELLER Sales exceed 100 000 copies T V FAULT FINDING 405 625 LINES jp e dy E 2282 4th REVISED EDITION Edited by J R Davies 124 pages only 8 6 Over 100 illustrations including 60 photographs of a television screen after the appropriate faults have been deliberately introduced Comprehensive Fault Finding Guide cross referenced to methods of fault rectification described at greater length in the text Price 8 6 from your Bookseller or post this Coupon together with remittance for 9 2 to include postage to DATA PUBLICATIONS LTD 57 Maida Vale London W 9 Please send me the 4th re vised edition of TV Fault Finding Data Book No 5 i I enclose cheque crossed postal order e Aa E AOL i
61. ED a_i 8 VALVE AUDIO AMPLIFIER HA94 MK II Designed for Hi Fi reproduc tion of records A C Mains operation Ready built on plated heavy gauge metal chassis size 73 w x 4 d X 42 h Incorporates ECCB3 EL84 EZ80 valves Heavy duty double wound mains tranaformer and output trans former matched for 3 ohm rpeaker Separate volume control and now with improved wide range tone controls glving bass and treble lift and cut Negative feedback line Output 4 watts Front panel can be detached and leada extended for remote mounting of controls Complete with knobs valves etc wired and tested for only 4 15 0 P amp P 6 HSL FOUR AMPLIFIER KIT Bimilar in appearance to HA34 above but employs entirely different and advanced pP aouit Complete set of parts etc 79 0 P amp P 6j HARVERSON S SUPER MONO AMPLIFIER A super quality gram amplifier using a double wound mains transformer EZ80 rectifier and ECL82 triode pentode valve as audio amplifier and power output stage Impedance 3 ohms Output approx 3 5 watts Volume and tone controls Chassis size only 7in wide x Sin deep x sin high overall AC mains 200 240v Supplied absolutely Brand New completely wired and tested with valves and good quality output transformer FEW ONLY J P amp P BARGAIN PRICE 6 HARVERSON SURPLUS CO LTD DE LUXE STEREO AMPLIFIER A C mains 200 240 v Using heavy duty fully isola ted mains transform er
62. Education etc Examination Students coached until successful N EW seve suio RADIO COURSES Learn as you build You can learn both the theory and prac tice of valve and transistor circuits and servicing work while building your own 5 valve receiver transistor portable and high grade test instruments incl professional type valve volt meter all under expert tuition Transistor Portable available as separate course POST THIS COUPON TODAY for full detaiis of ICS courses in Radio T V and Electronics gu e E E o M BRAND NEW FULLY GUARANTEED TRANSISTORS amp DEVICES INTEGRATED IN400L 1N 4002 1N 4003 1N4004 1N4005 1N 4006 1N4007 1N4009 1N4148 2210 2240 28301 2G302 28303 28306 2308 2G309 2G371 2G374 28381 20382 20383 2N404 2N896 2N697 i 2N698 2N706 2N706A 2N707 2N708 2N914 2N916 2N918 2N919 2N920 2N922 2N930 2N1131 2N1132 2N1303 2N1304 2N1305 2N1306 2N1307 2N1308 2N1309 2N1613 2N9147 2N2160 2N2287 2N7646 2N2904 2N 905 2N2925 2N2926 2N3011 E 2N3053 E 2N3054 2N3055 2N3702 2N3703 2N3704 2N3705 2N3707 2N3709 2N3710 2N3711 2N 37380 2N 3731 2N3794 2N3819 2N3820 2N3823 2N4058 2N4081 2N4286 2N 42868 2N4289 2N4290 2N4291 2N4292 40361 40362 2 AAZI 3 2 3 A4AZ13 2 6 A AZ17 AC126 8 6 AC127 4j REIA Z 5 A 1 6 Aro 1 9 AC169 12 8 AC153 49 8 AC176 4 AC187 4 6 AC188 ACY17 7 6
63. FOR AUTOMATION COMPUTERS ETC ALSO EXAMINATION COURSES FOR C amp G Telecommunication Technicians Certs C amp G Electronic Servicing R T E B Radio TV Servicing Certificate P M G Certificates in Radiotelegraphy Radio Amateurs Examination General Certificate of Education etc BUILD YOUR OWN RADIO AND INSTRUMENTS With an ICS Practical Radio amp Electronics Course you gain a sound knowledge of circuits and app lcatisn as you build your own 5 valve Superhet Receiver Transistor Portable and high grade test instruments incl professional type valve volt meter shown below Everything simply explained All components and tools supplied For illustrated brochure post coupon below e ee so mm ES t ENS N eee Rey N i X RADIO TELEVISION ELECTRONIC ENGINEERING Lez T d MEMBER OF THE ASSOCIATION OF BRITISH CORRESPONDENCE COLLEGES THERE IS AN i CS COURSE FOR YOU Whether you need a basic grounding tuition to complete your technical qualifications or further specialized knowledge ICS can help you with a course individually adapted to your requirements There is a place for you among the fully trained men lhey are the highly paid men the men of the future If you want to get to the top or to succeed in your own quc put your technical training in our experienced ands ICS Courses are written in clear simple and direct language fully illustrated and
64. GRUNDIG R T 40M GRUNDIG R T 100 LEAK Stereofetic LEAK teak s L L NOVA Tuner NIKKO Fam I2F PHILIPS RH690 aide ROGERS Ravensbrook FET Teak s ROGERS Ravensbourne FET Teak we SINCLAIR 2000 SANSUI TU555 SANSUI TU777 TELETON GTi0 TUNER AMPLIFIERS ARENA T 1500F ARENA T 2600 ARENA T 2700 ARENA T 9000 ARMSTRONG 525 ARMSTRONG 526 GOODMANS 3000 GRUNDIG RTV 400 GRUNDIG RTV 600 GRUNDIG RTV 650 LUX SQ 555 ves NIKKO STA 301 NIKKO ST 501 NIKKO ST 701 SANSUI 200 SANSUI 350 SANSUI 800 SANYO DC60E ROTEL 130 Smith s Radio Service Wolverhampton Ltd Rec Retail Discount Price Price 36 I5 O 29 10 52 0 0 44 0 59 0 O 48 O 25 O 0 17 O 30 0 O 2 IO 54 0 O 42 10 198 iS O 1 57 10 147 3 9 125 O 53 0 0 43 IO 59 10 O 48 12 65 0 O 53 IO 71 10 0 57 10 67 7 6 59 5 97 10 O 79 10 124 10 O 104 10 18 18 O 15 IO 30 9 O 22 10 32 0 0 27 0 36 0 O 29 19 46 10 O 39 10 95 10 O 50 I9 95 0 O 74 10 26 0 O 19 I9 98 0 O 85 O 45 0 2 37 IO 49 0 0 39 10 59 10 O 48 10 64 0 O 52 16 44 0 0 37 IO 59 10 O 49 10 108 O O 89 IO 62 17 7 51 10 80 9 7 65 0 30 9 0 23 15 20 10 28 7 0 20 0 38 5 01 29 0 44 2 Of 36 15 52 9 0 44 17 40 4 6 34 17 9 10 O 7 IS
65. Guaranteed U35 258 Planar trans PNP TO 182N2908 10j PHOTO DUODIODE MPECatianAUS TOP TEC E aeachi a BASE NO EQVT pss 95Sil Planar NPN trans TO 5 BFY 50 51 62 10 TYPE 15701 2N2175 or TAA263 Linear AF amplifier 18 6 each 9G371A OC71 Tape Readout high 8 2G374 OCz5 U37 30 Bil alloy trans 80 2 PNP 00200 98322 10 chi TAA293 General purpose amplifier switching and measure G 21 h 8 2G3744A OCSID U38 20 Fast Switching Sil trans NPN 400 Mc s2N3011 10 ment indicators 50V caca 8 2G381A OC81 U39 30 RF Germ PNP trans 2N1303 5 TO 5 10 250mV OUR PRICE 10 8 2G382T 0C82 EACH 50 OR OVER 8 6 8 2 6344A OC44 U40 10 Dual trans 6 lead TO 5 2N2060 seer ee eee ee ee T 10 EACH FULL DETAILS CA3020 RCA U S A LINEAR 8 2G345A 0C45 U41 25 RF Germ trans TO 1 0C4 NKT72 10 INTEGRATED CIRCUITS 8 26378 0078 Ui2 10 VHF Germ PNP trans TO 1 NKT667 AF117 10 FET S io P Amplifi 30 8 2G399A 2N1302 9NI38I9 me 2 ux 8 Audio Power Amplifier 30 each 8 2G417 AF117 Code Nos mentioned above are given as a guide to the type of 2N 3820 25 All 10 each pack device in the Pak The devices themselves are normally unmarked MPF105 8 6 BRAND NEW FULL TO MANUFACTURERS Price each nim SPECIFICATION 1 24 25 99 100 up o SAI S BP709 Operational Amplifier dual in line 14 pin pack a age 8N72709 and similar to
66. K Commonwealth Surface Mail 2 Air Mail 4 YORK ELECTRICS 335 BATTERSEA PARK RD LONDON S W 11 Send a S A E for full details a brief description and Photographs of all Kits and all 2 Radio Electronic and Photoelectric Projects Assembled 7 Te TO BUILD YOURSELF Backed by after sales service NEW roamer eight mk 1 WITH VARIABLE TONE CONTROL 7 Tunable Wavebanus Medium Wave 1 Medium Wave 2 Long Wave SW1 8W2 8W3 and Trawier Band Built in Ferrite Rod Aerial for Medium and Long Waves Five section 22in chrome plated Telescopic aerial for Short Waves can be angled and rotated for maximum per formance Push puli output using 600 mW transistors Socket for car aerial Tape record socket Selectivity switch Switched earpiece socket complete wlth earpiece for private listen ing Eight transistors plus 3 diodes Famous make 7in x 4in Speaker Air spaced ganged tuning condenser On Off switch volume control Wave change switch and tuning control Attractive case in rich chestnut shade with gold blocking Size 9 x 7 x 4in approx Easy to follow instruc tions and diagrams make the Roamer Eight a pleasure to build Total Building Costs f 6 1 o Parts Price List and Easy Build Plans 5 FREE with parts 8 E P amp P 7 6 roamer seven mk lV SEVEN FULLY TUNABLE WAVE BANDS MW MW2 LW SW1 8W2 SW3 and Trawler Band Extra Medium waveband provides easier tuning of Radio Luxembourg etc Built
67. Loft Mounting Arrays 7 clement 40 li element element 62 6 Wall Mounting with Cranked Arm 7 47 6 element 14 element 55 18 60 11 element 67 14 element 75 18 element 82 6 Mast Mounting with 2in clamp 7 element 42 6 11 element 55 14 element 62 18 clement 0 Chimney Mounting Arrays Complete 7 element 72 6 1 element 80 14 clement 87 6 18 element 95 Complete assembly instructions with every unit Cable 1 6 yd Low Loss U H F Preamps from 75 State clearly channel number required on all orders COMBINED BBCI BBC ITY AERIALS BBC Band 1 Loft 25 External S D 30 H 2 15 0 ITV Band 3 3 element loft array 30 5 element 40 7 element 50 Wall mounting 3 ele ment 50 5 element 55 Combined BBC ITV Loft 1 3 40 1 5 50 1 7 60 Wall mounting Scy 1 4 3 70 1 5 Mi transistor pre amps e ITY BBC2 a AERIALS 1 3 9 70 1 5 9 80 1 5 14 90 1 7 14 100 Loft mounting only F M Band 2 Loft S D 17 6 H 35 3 element 57 6 External units available Co ax cable 8d yd Co ax plugs 1 6 Outlet boxes 5 Diplexer Crossover Boxes 17 6 C W O or C O D P amp P 6 6 Send 6d stamps for illustrated lists Callers welcomed open all day Saturday K V A ELECTRONICS Dept P W 40 41 MONARCH PARADE LONDON ROAD MITCHAM SURREY
68. London 21851 SEMICONDUCTORS BRAND NEW AND FULLY GUARANTEED 1N914 2N2923 IN916 2N2924 18021 2N2925 18025 2N2926 18113 Green 3 AF118 18120 Yellow 2 6 AF124 18121 Orange 2 6 AF125 8 18130 2N3011 18131 2N 3053 18132 2N3054 1844 2N3055 18920 2N3702 26301 2N3703 20302 2N8704 26308 2N3705 26 308 2N3706 2G371 2N3707 2N696 2N3708 2N697 2N3769 2N698 2N3710 2N706 2N3711 2N706A 2N3819 2N708 2N3820 2N 930 2N3906 oN1131 2N1132 2N1302 2N1303 2N1304 2N 1305 2N1306 2N1307 21308 2N1309 2N1507 2N1613 2N4291 QNi711 2N4299 2N1889 40361 2N1893 40362 QN2102 3N198 9N2147 3N140 9N2148 3N141 2N9160 3N149 9N2193 AAZI3 QN2194A AAZI5 QN2217 AAZI 2N2218 AC107 2N2219 AC126 2N2220 AC127 ON2991 ACI28 9N2229 AC176 2N2368 ACI87 2N2369 ACI88 2N2369A ACY17 2N2539 ACVIS 2N2540 ACY19 2N9646 11 6 ACY20 2N2904 7 ACY 1 QN2904A 8 ACY22 2N9905 amp ACY28 QN2005A 9 AD140 2N2906 6 AD149 ON2906A 6 6 AD161 2N 4058 2N4059 2N4060 2N4061 2N4062 2N 4284 2N4285 2N4286 2N4287 2N4288 2N4289 MPF102 MPF103 MPFi04 MPFT105 NKTO0013 NKT216 NKT217 NKT261 NKT262 NET264 NET271 NKT272 NKT274 NKT275 NKT281 NKT403 NKT404 NKT405 NKT613 NKT674 NET677 NKT713 NKT773 NKT781 NKT20329 8 6 NKT8011115 6 36 ADI62 X 7 6 BDI32 3 6 AF114 5 BD142 3 6 AF116 5 BF115 AFi7 5 BF117 BF167 BF173 BF180 BF181 BF184 BF194 BF195 BF197 BF244 BFN
69. R20 U801 8 VABC80 6 6 UAF42 10 8 UBU41 READERS RADIO 85 TORQUAY GARDENS REDBRIDGE ILFORD ESSEX UCH42 UCHSB1 ZU Transistors AC107 AC127 AD140 AFII5 S ETS Bet of 4 tor 18 6 DAF98 DF 96 DK96 DL96 4 FOR 29 OZ4 4 6 20P3 11 9 DK96 7 8 A 4 9 1A7GT 7 6 20P4 18 6 DL95 5 EL9O 5 3 1H5GT 7 3 25L6GT 5 DL92 5 9 ELMO E 1NBGT 7 8 25U4GTI1 80 DL94 6 3 1R5 5 9 30C1 6 6 DL96 7 8 Emei 8 3 185 4 3 30C15 18 DY86 5 9 EM84 6 9 1T4 2 9 30017 16 DY87 5 9 EM87 7 6 84 6 9 30C18 13 6 EABC80 6 6 EYS 7 8 3v4 6 8 30F5 16 EAF42 10 EY86 6 6 SY3GT 5 0 30FLI 12 9 EBO1 2 8 EZ40 8 5Z4G 7 6 30FLI214 6 EBCS3 6 EZ4l 8j 6 30L2 12 S0FL14 14 6 EBC41 9 6 EZ80 4 6 GALS 2 8 80L1 6 6 EBF80 6 9 EZ81 4 0 6AM8 2 9 30L16 18 EBF89 6 3 GZ32 8 9 6AQ5 6 8 30L17 15 6 ECCS1 3 9 KT41 15 6 6AB6 6 30P4 18 ECC82 4 9 KT61 9 amp AT8 4 30P12 13 9 ECC83 7 KT66 16 GAUG 4 6 30P19 12 ECC85 5 LN329 14 6 6BA6 4 6 30PLI 18 8 ECC80412 N78 17 6 6BE6 4 9 30PL13 15 6 ECF80 6 6 P61 10 6BJ6 amp 6 6 30PL1414 6 ECF82 6 6 PABC80 7 6CbG 4 9 35L6GT 8 9 ECH35 6 PCB 10 3 6F14 9 35W4 4 6 ECH42 Ms PC88 10 8 6F23 14 8 35Z4GT 5 ECH81 5 9 PCo5 8 6 8F95 18 6063 12 8 ECH83 8 3 PC97 8 6J5G 4 9 807 9 ECH84 7 6 PC900 op 6K7G 2 8 AC VP215 6 ECL80 7 PCC84 6K8G 2 9 AZ31 9 8 ECL82 6 9 PCC85 hi 68N7GT 4 3 B349 18 ECL86 8 PCC88 m
70. SPECIAL OFFER HI FI LOUDSPEAKER SYSTEM Beantifully made teak finish enclosure with most attractive Tygan Uynair front Size 163 high x 10i wide x 6 deep Fitted with E M I Ceramic Magnet 13 x 8 bass unit two H F tweeter units and crossover Power handling 10 watts Available 3 or 15 ohm impedance 8 Gns Carriage 10 TRANSISTOR STEREO 8 8 MK II Now using Silicon Transistors in first five stages on each channel resulting in even lower noise level with improved sensitivity A really first class Hi Fi Stereo Amplifier Kit Uses 14 translators giving 8 watts push pull output per channel 16W mono Integrated pre amp with Bass Treble and Volume controls Suitable for use with Ceramic or Crystal cartridges Output stage for any speakers from to 15 ohms Compact design all parts supplied including drilled metal work Cir Kit board attractive front panel knobs wire solder nuts bolts no extras to buy Simple step by step instructions enable any constructor to build an amplifier to be proud of Brief specification Freq response 3dB 20 20 000 c s Bass boost approx to 12dB Treble cut approx to 18bB Negative feedback 18dB over main amp Power requirements 25V at 6 amp PRICES AMPLIFIER KIT 10 10 0 POWER PACK KIT 43 0 0 CABINET 23 0 0 All Post Free Also available STEREO 10 10 As above but 10 watts per channel PRICES AMPLIFIER KIT 12 POWER PACK KIT 3 10 0 Circuit diagram con
71. Service Sheets strictly by return of post Please state make and model number alternative Free TV fault tracing chart or TV list on request with order Mail order only 404 SERVICE SHEETS continued RADIO TELEVISION over 3 000 ME JOHN GILBERT TELEVISION lb Shep herds Bush Rd London W 6 SHE 8441 SERVICE SHEETS 75 000 5 each please add loose 4d stamp callers welcome always open THOMAS BOWER 5 South Street Oakenshaw Bradford SERVICE SHEETS Radio TV etc models List 2 S A E enquiries RAY 11 Maudland Bank Preston oe mao TRADER SERVICE SHEETS 5 each plus postage 8 000 TEL We can supply Trader Service Sheets for most makes and types of Radios Tape Recorders and Televisions Manuals for some Cheques and open P O s returned if sheets not availabie DAKFIELD ENTERPRISES LIMITED 30 CRAVEN STREET STRAND LONDON WC2 Make Mode Radio TV eg i ee 00 1970 List now available at 2 plus postage Iflistisrequired indicate with X enclose remittance Of and a stamped addressed envelope s a e with enquiries please MAIL ORDER ONLY February PW BOOKS amp PUBLICATIONS SURPLUS HANDBOOKS 7 0 p p 9d 7 0 p p 8d 6 0 p p d 6 0 p p 9d 8 0 p p 9d 7 6 pjp 9d 6 0 p p 9d 6 0 p p 9d 19 set Circuit and Notes 1155 set Circuit and Notes H R O Technical instructions 38 set
72. Triple Play A LONDON MUS 2639 3in 300ft 4 4in 900ft 13 10 Tottenham Court Road din 600ft 8 Sin 1 800f 28 Xx PORTSMOUTH Tel 22034 Sin 1 200ft 15 53 amp in 2 400ft 34 350 382 Fratton Road Sin 1 800ft 19 64 Tin 3 600ft 44 x SOUTHAMPTON Fin 2 100ft 27 Quadruple Play 72 East Street Tel 25851 Jin _ 600ft 8 6 BRIGHTON Tei 23975 Postages l reel 6 Queen s Road Post Free lesa 5 on three reels Quantity and Trade enquiries invited Ali mail orders to DEVONIAN COURT PK CRES PLACE BRIGHTON Te 680722 AMPLIFIERS ARENA F210 ARMSTRONG 521 CORAL 550 DULCI 207 ULCI 207M ioni GOODMANS Maxamp GRUNDIG SVI40 m GRUNDIG sv85 AR LEAK Stereo 30 plus chassis em LEAK Stereo 30 plus teak s LEAK Stereo 70 chassis LEAK Stereo 70 teak LUX SQ 77T LUX SQ 505 LUX SQ 1220 INEAR LT 66 L L NOVA AMP Rar METROSOUND ST20 NIKKO TRM 30 NIKKO TRM 40K NIKKO TRM 50 NIKKO TRM 120 PHILIPS RH 580 QUAD 33 and 303 ROGERS Ravensbrook ROGERS Ravensbrook Teak em e ROGERS Ravensbourne Teak e T ROTEL 100 E SUGDEN A51 Mk 2 J E SUGDEN A51 CSI SANSUI AU 222 sine SANSUI AU 555 SINCLAIR 2000 dum SINCLAIR project 60 with PZ5 s TELETON SAQ 203E TELETON GA IOI FM TUNERS ARENA F2Il ati ARMSTRONG 523 ARMSTRONG 524 ARMSTRONG M8 Dec DULCI FMT7 wie DULCI FMT7S a GOODMANS Stereo max POS A
73. W O No C O D ON2996 3 ACY39 I2 6 BY100 4 6 0Cl6 13 0 OCT 4j OCB 3 0Cl72 7j Tube postage 10 each 2N3705 4 ADI49 12 GETli4 4 OC19 8 6 OC73 7 3 0C82D 3 OCo00 5 6 f 2N3819 8 ADI6l 7 6 GJ7M 6 6 0C90 20 0C74 4 6 OU83 4 6 OC201 8 6 Special Express Mail Order Service ACIO7 5 6 AD162 7 NKT274 4 9 OC98 12 6 0675 4 8 OC84 4 9 0C202 8 6 AC127 5 AF117 4 63lNKT713 7 61 0C35 6 31 0C76 3 OCll4 7 6 0C203 6j _ SEND S A E FOR LIST OF 3 000 TYPES o a MMM M M M M A me AMPLIFIER FOR MAGNAVOX TAPE DECKS 4 TRACK CAN BE USED FOR 2 TRACK IUE Heo doo o Chassis 12 x 5j x 4jin finished in Black and Silver 200 250 A C Record Playback amp switch Off On Tone Vol Me Vol Gram Mic Input Gram Input Valves 6BR7 12AX7 EM84 EL84 and EZ80 Separate Output Trans former Already wired to amp PRICE 12 10 P amp P 3 ohm speaker 7 x 4 16 extra high Plastic front panel STEREO AMPLIFIER type HV 2x3 Watts E Fully built On off sep vol and tone each channel 12 x 41 x Gin high EZ80 2 x ECLB6 for 3 ohm speakers double wound main trans fixing flanges and base plate suitable for crystal cart tuner etc 6 10 0 8 p amp p 200 250V A C Superior version separate base treble amp vol each channel with mono stereo switch 15 extra m STEREO AMPLIFIER type RC 2 x 3 Watts for 200
74. WITH COVERS Complete not wired SP25 3 Way Speaker System 14 12 6 p p 15 Ready wired Teak cabinet size 141 x 8 x 6 with 5 pin DIN or Phono 10 6 extra 10watts peak 5 19 6 p p 7 6 For any other deck 3000 2025TC SL65B add price of deck to Best Stereo Headphone 80 plinth and cover and 15 p p and good quality 52 6 p p 5 10 6 for wiring AUDIO SUPPLIES cuors m Callers 50A STAMFORD HILL LONDON N 16 Mail orders 103A DALSTON LANE LONDON E 8 Quote PW TELEPHONE 01 806 3611 or 01 254 4957 Open Mon Sat 9 a m 6 p m Thur half day Open Sunday 10 a m 2 p m 341 This MONTH S Best Buy AKG K50 Dynamic Stereo headphones Complete with spare ear muffs Total Our 4 6 ur 10 8 0d Price 5 1 p amp p Available only from us at this price Due to entire purchase of manufacturer s remaining stock this fantastic offer is open only while stocks last High fidelity reproduction due to broad frequency response 20 20 000Hz Substantially increased stereo effect Headphones fit the head gently and do not shitt Earpieces fit ears snugly Cardanic suspension Tone quality superior to conventional loudspeakers Only expenslve studio loud speakers can match the reproduction quality of the K50 Music can be reproduced at concert hall volume preserving the lower bass notes and brilliant treble tones without causing any strain to the Ilstener
75. and dial with polished brass inserts Size 9 x 51 x 2jin approx Tunable on Medium and Long Waves three Short Waves and Trawler Band Sensitive ferrite rod aerial for M W and L W Telescopic aerial for Short Waves Eight improved type transistors plus 3 diodes Push pull output Battery economiser switch for extended battery life Ample power to drive a larger speaker Parts price list and easy build plans 5 FREE with parts Earpiece with switched socket for private listening 5 extra Total building costs P amp P 5 6 transona five MEDIUM WAVE LONG WAVE AND TRAWLER BAND PORTABLE WITH SPEAKER Attractive case with red speaker grille Size 6 x 4 x Liin 7 stage s transistors and 2 diodes ferrite rod aerial tuning condenser volume control fine tone moving coil speaker Easy build plans and parts price list 1 6 FREE with parts Total building costs 476 5 Tel 0234 52367 l WE P enclose please send items marked t Mtaani Aer um gilt fittings Size 74 x 5t x liin e on Medium an ong wares two xn AES Trawler Band Plus an iride M W band I ROAM ER EI G HT L R OAM ER SEVEN T for taleg TONE eta Od E PESE i TRA 1 aerial an elescopic ri or or wave 8 stages 6 translators os s cad Total building costs l a E 3 TRANS NELA E l i MES ors etc in strap 1 6 CR aey Dude ARO bane e P amp P POCKET FIVE L ROAM ER SIX E I list 2 FREE with parts Note When
76. answer technical queries over the telephone e It helps us if queries are clear and concise f We cannot guarantee to answer any query not accom panied by the current query coupon and a stamped addressed envelope 382 and on the control panel there is an indicating pilot bulb which shows the intensity of the filament light ing of the valves The valve filament lighting is effected from the starting and lighting battery of the car High tension batteries of the usual type are fitted in the same compartment as the receiver In order to prevent interference from the ignition and lighting equipment of the car the magneto and generator are screened Two pairs of double earpieces and two single earpieces may be employed so that four persons can listen in at once The effective receiving range of the equipment is approximately fifty miles radial distance from a broadcasting centre when used with the frame aerial fitted to the car roof When all the broadcasting stations are in operation a car fitted with this apparatus will therefore practically be within range of broadcast Vintage CA Should readers wish to have a Vintage CQ published we will be prepared to accept letters for inclusion They will of course be inserted in the magazine when space permits and will be dealt with in strict rotation Therefore if you have any queries on old gear want to exchange or obtain vintage equ
77. at the requisite tremulant rate between 5 and 10Hz as required The signals that pass through the tone tremulant circuit are modified and the harmonic structure changed by means of the primary inductance of T3 and its RC network The signals are phased reversed at the primary and therefore appear at the output of the tone tremulant amplifier in phase with signals direct from the guitar pre amplifier The result is a complex variation at tremulant rate of the higher harmonics produced by the guitar the aural effect being akin to that obtained with a rotating loudspeaker tremulant system Leslie speaker The effect is much more pleasing than the usual straight amplitude variation tremulant used in com mercially made amplifiers The tonal quality of the tremulant is continuously variable and when tumed off leaves a normal amplitude tremulant only the tone of the guitar remaining unaffected This too can be switched off but the tone tremulant control can still be used as a tone control for the guitar providing even stronger upper harmonic sounds than those produced by the treble lift control The mixed outputs from the guitar pre amplifier and the tone tremulant circuit are then taken to the mixing pre amplifier together with the output from the microphone pre amplifier The mixing pre amplifier output is then connected to the power amplifier module via the master volume control Tremulant Control System The tremulant control c
78. boards and battery etc has to be built up onto the frame itself This top cover is tin plywood and can be used for making the end pieces of the case Those who wish to make the pedal frame and pedals will find the dimensions etc in the various diagrams The main frame is shown in Fig 2 A and B and made from soft planed wood Note that the rear member of the frame the pedal support rail is bevelled to the dimensions given in Fig 2B The front main member of the pedal frame is fitted with guide posts for the pedals as shown in Fig 3 These posts are made from amp in diameter dowel and are glued in so that they just clear the upper pedal stop rail see inset Fig 3 Next the pedals themselves should be made and checked for fitting within the frame but not secured until the case frame work has been completed Details of the pedals 8 white and 5 black are given in Fig 4 Note the soft leather or plastic binder around each pedal a couple of turns of adhesive plastic insulating tape will do and also the small hardboard pads which press on the keying contacts Each pedal is secured to the rear member of the main frame by means of a flat phosphor bronze spring details of which are given in Fig 5 Do not bend these strips they will bend themselves Fig 6 when the pedals are finally fitted and the springs secured to the rear pedal support rail 208 a qa AH 23 3 o t Slot for a contact bar ies rb Fig 2 C
79. can give yourself the essential technical know how sooner than you would have thought possible read circuits assemble standard components experiment build and enjoy every moment of it B 1 E T s Simplified Study Method and the remarkable new TECHNATRON Self Build Outfit take the mystery out of the subject make learn ing easy and interesting Even if you don t know the first thing about Radio now you ll build your own Radio set within a month or so and what s more YOU LL UNDERSTAND EXACTLY WHAT YOU ARE DOING The Tech natron Outfit contains every thing you need from tools to transistors even a versatile Multimeter which we teach you how to use You need only a little of your spare time the cost is surprisingly low and the fee may be paid by convenient monthly instal ments You can use the equipment again and again and it remains your own property You LEARN but it s as fascinating as a hobby Among many other interest ing experiments the Radio set you build and it s a good one is really a bonus this is first and last a reaching Course But the training is as rewarding and interesting as any hobby It could be the springboard for a career in Radio and Electronics or provide a great new spare time interest BRITISH INSTITUTE OF ENGINEERING TECHNOLOGY Dept 372b Aldermaston Court Aldermaston Berkshire A 14 year old could under stand and benefi
80. enables unit to be used with cover in position OUR PRICE 5 15 0 complete P amp P 8 6 EEE E TT DEQESEQOREQcQ LAUS LATEST ACOS GP91 18C mono compatible cartridge with t o AVES Hh LP EP 78 Universal mounting bracket 30 P amp P 1 6 SONOTONE 2539 High output Stereo Cartridge T O stylus for Btereo LP 78 Complete with universal mounting bracket List Price 48 7 OUR PRICE 25 P amp P 1 6 SONOTONE 9TAHC compatible Stereo Cartridge with diamond stylus 50 P amp P 2 LATEST RONETTE T O STEREO COMPATIBLE CARTRIDGE for EP LP Stereo 78 32 6 P amp P 2 LATEST RONETTE T O MONO COMPATIBLE CART RIDGE for playing EP LP 78 mono or stereo records on mono equipment Only 80 P amp P 2 HIGH GAIN 4 TRANSISTOR PRINTED CIRCUIT AMPLIFIER KIT Type TAL Peak output in excess of l watts All standara British com ponenta Built on printed cir cuit panel size 6 x 3in Generous size Driver and Output Trans formers Output transformer tapped for 3 ohm and 15 ohm speakers Transistora GET114 or 81 Mullard ACI28D and matched pair of AC128 o p 9 volt operation Everything supplied wire battery clips solder etc Comprehensive easy to follow instructions and circuit diagram 2 6 Free with Kit All parts sold separately SPECIAL PRICE 45 P amp P 3 Also ready built and tested 52 6 P amp P 3 1014 WATT HI F1 AMPLIFIER KIT A stylishly finished monaural amplifier wi
81. fixing holes on the PW25 50 chassis The Henelec power module and power supply are tested before despatch so that no circuit adjustment whatever is necessary Pre amplifier and Control Circuit The block diagram in Fig 1 may help to clarify the various functions of the pre amplifier and tremulant control stages The two guitar inputs can be mixed ie each can be adjusted for volume independently of the other The inputs are suitable for all medium to high impedance guitar pick ups and the sensitivity of each input is 40mV for maxi mum rated power output Signal levels of 1 volt or more can be taken to these inputs and with the tremulant switched off they can be used for signals from other sources such as the output from a portable electronic organ a tape recorder or high output gramophone pick up etc The guitar pre amplifier also has a treble control which provides approximately 15dB lift at 10 000Hz This has been included as many guitarists favour a tone with a strong upper harmonic content New Tremulant System The signal output from the guitar pre amplifier is passed to a network which routes the signal via the tremulant l d r Light Dependent Resistor to the tone tremulant amplifier and also directly to the input of the mixing pre amplifer The ld is controlled by means of a lamp the brilliance of which is made to vary sinusoidally When the phase shift oscillator is running the amplitude of the guitar signals is varied
82. for production line testing of transistorised electronic equipment Applicants should preferably possess either a formal qualification in radio servicing or testing or have obtained equivalent experience in similar work Location Bradford Yorkshire The positions carry staff status and good salaries will be paid to the successful candidates There is a contributory pension scheme and free life assurance benefit Assistance with applicable Applications to removal expenses will be paid if The Personnel Manager Rank Wharfedale Limited Bradford Road AUDIO VISUAL DIVISION Tel Idle Bradford BDIO 850 Yorkshire Bradford 612552 The Rank Organisation The man with the gong a man of many skills ENGINEERS A TECHNICAL CERTIFI CATE or qualification will bring you security and much better pay Elem and adv private postal courses for C Eng A M E R E A M S E Mech amp Elec City amp Guilds A M LM L A B and GCE Exams Diploma courses in all branches of Engineering Mech Elec Auto Electronics Radio Computers Draughts Building etc For full details write for FREE 132 page guide BRITISH INSTITUTE OF ENGINEERING TECH NOLOGY Dept 169K Aldermaston Court Aldermaston Berks ELECTRONICS TECHNICIAN JUNIOR TECHNICIAN 16 20 required for Psychology Department to assist in development construction and maintenance of electronic equipment for use in teachin
83. illustrated A cross reference Index and a 30 page Price List enable you to locate your components without any trouble Ai Once you have your Home Radio Catalogue you can PRE gt if you wish make life even easier for yourself by join ing our Credit Account Service Then you can order by telephone any time of day or night Sundays in cluded No need to bother with postal orders cheques registering envelopes every time you order We send prepaid envelopes and only one payment is required each month So simple Write for details or telephone 01 648 8422 POST THIS COUPON NOW with your cheque or P O for 12 6 j M mm 3 CS OMNEA E Please write your Name and Address in block capitals i dirus Sce oem Edge DA cado DCD A O o Soo EEE Tacna oes The price of 12 6 applies only to catalogues purchased by customers residing in the U K HOME RADIO Components LTD Dept PW 234 940 London Road Mitcham Surrey CR4 3HD gum ee eee BRAND NEW ARS8D COMMUNICATIONS RECEIVERS AC maine input 110 volts or 250 volts Frequency in 6 bands 535 k cs up to 32 megs Output impedance 2 5 600 ohms Complete with crystal filter noise limiter B F O HF tone controls Price 80 including spare set of valves headphones and manual R209 RECEIVER AM CW FM 1 20 Mc s Four bands Vernier tuning 12 volt DC input Tested and working Price 218 10 0 plus 1 p p COMPUTER BOARDS Min 30 transistor
84. kit Standard 3 ohm output Frequency response 2db from 12 to 12000 cps on board measuring 24 x 34 im Ideal record players etc Manley S E 26 22s 6d each pp Is 6d A lit Mayow Road Sydenham TOP TRANSISTORS ACY22 1 9 BFY5I 1 9 OC2O0 1 9 BCIO8 1 9 BFY52 1 9 OC202 1 9 BCIO9 1 9 OC45 1 9 ZTX300 1 9 BCl 68 1 9 OC7 1 9 2N706 1 9 BCl69 1 9 OC72 1 9 2N2926 1 9 BSY27 1 9 OC200 1 9 2N3708 1 9 All the above types are available at 16 for I Brand New Individually Tested unmarked but guaranteed to be within their correct specification or money refunded ANTEX SOLDER IRON A lightweight iron with a I5 watt nickel plated bit Designed to enable you to weld reliable joints accurately Model CN240 volts Special low price Act Now Only 29111 MONEY BACK GUARANTEE P amp P J M KING R 17 Buckridge Portpool Lane London E C l TEL GOOD CONNECTIONS take seconds with the revolutionary new Keynector Cuts out plugs sockets and dangers from bare wires Just the job for high speed testing of elec tronic equipment A must for the do it yourself enthusiast Send for leaflet to E B Instruments Dept P W 49 53 Pancras Road London E W 1 837 7781 Only 46 6d plus postage ditado TV NOTES FOR UFO DETECTION and 2 Optical Detector circuits 9 6 All night Optical Radiation circuit with electronic memory 9 6 Radar amp Electronic Pub lications Highl
85. m LOWTHER Acousta PM6 MORDAUNT SHORT MS 100 alo e MORDAUNT SHORT MS 600 FA PHILIPS RH481 per pair PHILIPS RH48 per pair SINCLAIR QI4 per pair SANYO SX X per pair SANYO SX6 per pair WHARFEDALE Denton WHARFEDALE Super Linton nas bes WHARFEDALE Melton WHARFEDALE Dove dale If Pas WHARFEDALE Aire dale de Rita WHARFEDALE Rose dale zs es WHARFEDALE Unit 3 WHARFEDALE Unit 4 WHARFEDALE Unit 5 PLAYING DECKS GARRARD 401 GARRARD SL95B GARRARD SL75B GARRARD SL65B GARRARD SP25 GARRARD AP75 sae GARRARD 2025 T C GOLDRING GL69 GOLDRING GL69D GARRARD GL75 GOLDRING GL75P GOLDRING G99 GOODMANS 3025 THORENS TDISO A Mk Il J5 bas THORENS TDI50 AB II THORENS TDI24 II THORENS TDI25 THORENS TD125 AB Rec Retail Price 74 83 39 51 64 69 100 19 22 32 10 78 18 17 32 63 139 21 40 57 66 86 176 22 29 43 37 39 69 57 11 16 23 31 45 35 19 15 23 El 25 33 36 46 24 37 43 47 46 75 120 19 0 10 19 12 10 10 10 0 I9 0 Io 14 9 12 6 I5 16 3 11 8 18 14 14 I2 8 15 i7 3 STEREO CARTRIDGES AUDIO TECHNICA AT66 fas AUDIO TECHNICA AT21S T AUDIO TECHNICA AT2IX E 8 4 l4 ococooOooo0O00 2000 o O oo 06060u000 o o Oooooo4ooooo OUO ooonmoooooooooo 0 O0 w O0
86. made the circuits can be produced with complete uniformity and at very low cost This enables us to cover every IC 10 with the Sinclair guarantee of reliability Sri MONOLITHIC INTEGRATED CIRCUIT HIGH FIDELITY AMPLIFIER AND PRE AMP high fidelity amplifier E SPECIFICATIONS Output 10 Watts peak 5 Watts R M S continuous Frequency response 5 Hz to 100 KHz 1dB Total harmonic distortion Less than 1 at full output Load impedance 3 to 15 ohms Power gain 110dB 100 000 000 000 times total Supply voltage 8 to 18 volts Size 1 x 0 4 x 0 2 inches Sensitivity 5mV Input impedance Adjustable externally up to 2 5 M ohms E CIRCUIT DESCRIPTION The first three transistors are used in the pre amp and the remaining 10 in the power amplifier Class AB output is used with closely controlled quiescent current which is independent of temperature Generous negative feed back is used round both sections and the amplifier is completely free from crossover distortion at all supply voltages making battery operation eminently satis factory E APPLICATIONS Each IC 10 is sold with a very comprehensive manual giving circuit and wiring diagrams for a large number of applications in addition to high fidelity These include stabilised power supplies oscillators etc The pre amp section can be used as an R F or I F amplifier without any additional transistors POST FREE SINCLAIR with 1C 10 a manual SINCLAIR RADIONI
87. new style course will enable anyone to really understand electronics by a modern practical and visual method no maths and a minimum of theory no previous knowledge required It will also enable anyone to understand how to test service and maintain all types of Electronic paste Radio and TV receivers etc UERPEP os now T ERU m sum sum uum cung NB ED ED eee GRUB ED um UD ND UD UD 4m des NOW To BRITISH NATIONAL RADIO SCHOOL READING BERKS Please n send your free Brochure without obligation to we do not employ representatives l l l or write if you prefer not to cut page ADDRESS 5 23 a es Iter RE em ee ny wed PACE P W 9 344 TOPIC OF THE MONTH PRACTICAL WIRELESS NEWS AND COMMENT VOL4E NOS Issue 763 SEPTEMBER 1970 Leader 345 Showtime News News NewS 346 EMPUS as they say certainly fugits And here we are On the Short Waves i once again in that fag end of the British summer which by Malcolm Connah and as become known traditionally as show time To add David Gibson G3JDG 359 emphasis to this exhibition oriented season the annual RSGB show has thls year moved up from its usual MW Column by Charles Molloy 365 October date to August finishing at the time the round Practically Wireless by Henry 389 of annual radio trade shows begin It is hoped that regular visitors to the RSGB show known officially as the Inter E M national Ra
88. on first kit then 3 6 on each two kits ordered 3 DIGIT COUNTER For Tape Recorder or other application re settable by dep ressing button Price 5 6 TRANSDUCER Made by Acos reference No 1 D 1001 For measuring vibra tion etc to be used in con junction with G Meter Regu lar price 5 Our price 49 6 Brand new and unused ISOLATION SWITCH 20 Amp D P 950 volts Ideal to con trol Water Heater or any other appli ance Neon indicator shows when current is on 4 0 48 per dozen LIGHT CELL Almost zero resistant in sun light increases to 10 K Ohms in dark or dull light epory resin sealed Size approx lin dla by lin thick Rated at 500 MW wire ended 8 6 with circuit FLEX BARGAINS Screened 2 Core Flex Each core 14 0076 Copper PVC insulated and coloured the 2 cores lald to gether and metal braided overa l Price 2 15 0 per 100 yds coil p amp p 6 8 15 Amp 8 Core Non kink Fier 70 0076 Insulatea coloured cores protected by tough rubber sheath then black cotton bralded with white tracer A normal domestic flex as fitted to 3 Kw fires Regular price 3 6 per yd 50 yd coll 4 10 0 p amp p 0 8 10 Amp 8 Core Non kink Flex As above but cores are 28 0076 Copper Normal price 2 6 per yd 100 yd coil 7 10 0 p amp p 6 6 8 Amp 2 Core Flex As above but 2 Cores each 28 0076 as used for Vaouum Cleaners Electric Blanketn etc 89 6 100 yd coll p amp p 6 6 28 0
89. p switch 2 pos mono and 2 pos stereo Separate on off switch A preset Cover and teak finish plin ea 4 4 0 7 6 p amp p Duo Type speakers see opp page dual ganged volume control balance control The above items purchased together 29 10 0 1 10 p amp p 332 e CAR TRANSISTOR IGNITION SYSTEM by famous manufacturer For 6 volt or 1 volt positive earth systema Comprising special high voltage working hermetically gealed eilicon transistor mounted in finned heat sink high output ignition coil ballast resistor and hardwear screws washers etc Price 4 19 6 plus 5 P amp P THE DUO SPEAKER SYSTEM Bimilar in design to those on the previous page the 2 way speaker system is beautifully finished in polished teak veneer with matching vynair grille It is ideal for wall or shelf mounting either upright or horizon tally Type 1 SPECIFICATION Impedance 3 8 or 10 ohms please state requirement It incorporates Goodmans high flux Gin x 4in speaker and 2ii speaker Teak finish 12in x in x oiin 4 guineas each 7 6 p amp p 50 WATT AMPLIFIE Ic A C Mains T y 200 250V Price 28 10 plos 20 p amp p An extremely reliable general purpose valve amplifier Its rugged construction yet space age styling and de sign makes it by far the best value for money TECHNICAL SPECIFICATIONS 3 electronically mixed channels with 2 inputs per channel enables
90. p 3 way 4 6 each 1 gam DIAMETER Wavechange MAKITS 1 p 12 way 2 p 9 way 3 p 4 way 4 p 8 way 6 p 2 way 1 wafer 12 2 wafer 18 8 water 24 4 water dica b water 36 TOGGLE SWITCHES sp 2 8 sp dt 3 8 dp 3 6 dp dt 4 8 ALL PURPOSE HEADPHONES H R HEADPHONES 2000 ohms Super Sensitive LOW RESISTANCE HEADPHONES 3 5 ohms DE LUXE PADDED STEREO PHONES 8 ohms THE INSTANT BULK TAPE ERASER AND EIER E DEMAG NETISER 42 6 Post 2 8 Minimum Post and Packing 2 6 RETURN OF POST DESPATCH RADIO COMPONENT SPECIALISTS List Written guarantee with every purchase Export Remit cash and extra postage Buses 133 68 pass door S R Stn Selhurst GENERAL PURPOSE TRANSISTOR PRE AMPLIFIER BRITISH MADE for Mike Tape P U Guitar Battery 12v or H T line 200 300v D C operation Size 13 x 1j x Response 25 o p s to 25 Ks s 26db gain For use with valve or transistor equipment Full instructions supplied Brand new cerle Details S A E 17 6 each NEW TUBULAE ELECTROLETICS CAN TYPES 2 3507 2 6 100 25V 2j 16 18 500V 11 4 j850V 2 8 250 25V 2 6 50 60 350V 71 8 450V 2 6 5B00 25V ala 60 100 350V 11 6 18 450V 3 8 8 450V 3 6 824 82 250V 3 6 82 450V 4 84 16 450V ay 82 82 A50V 8 6 5 25V 2 16 18 450V 5 32 32 32 350V 6 0 50 50V 2 82 82 850V 5 100 50 50 350V 9 6 SUB MIN ELECTROLYTICS 1 2 4 5 8 16
91. pre amplifier Tri Tr2 Guitar 1 Guitar 2 LDR control Guitar pre amplifier Tr5 Tr6 Treble control Guitar 1 Guitar 2 volume volume Tone tremulant amplifier Tr7 Tremulant depth LOR Control amplifier Tr Master volume control Mixing pre amplifier Tr8 Tr9 Tremulant tone control Fig 1 Block diagram illustrating the function of each stage of the amplifier effect can be obtained with a pedal operated potentio meter which can also be plug and socket connected to the guit r pre amplifier Power Amplifier Module and Power Supply To facilitate construction for those with little experience in building and testing transistor power amplifiers modules and regulated power supplies the new Henelec 50 watt power amplifier module type PASO and its matching power supply Henelec type MU442 have been chosen for the power output end of the PW25 50 As previously mentioned the Henelec PA50 module will deliver 50 watts r m s into a 4 ohm load or 25 watts to an 8 ohm load Hence the reason for the designation PW25 50 and the use of either one or a pair of 8 ohm loudspeakers The Henelec PA50 module and its power supply are supplied complete with connecting cables ready wired to the connectors DIN loudspeaker plugs a DIN signal input plug and a 3 pin mains input connector To mount these units it is only necessary to drill the appropriate
92. present J i stocks of these cases are exhausted a new case 4 6 pilar OM pan Sei Eh META MEE SOT SQ Parts price list and plans for s sss n I ise ind Name SE Ss pet ee ee ee a pee e RT i Callers side entrance Stylo Shoe Shop I adress j Open 10 1 2 30 4 30 Mon Fri 9 12 Sat d ALI 399 ELEGTROVALUE EVERYTHING BRAND NEW amp TO SPECIFICATION e LARGE STOCKS BARGAINS IN NEW SEMICONDUCTORS ill power types supplied with free insulating sets PEAK SOUND PRODUCTS 1N914 1 8 2N8706 3 3 40512 45 8 BCI47 3 6 BFY51 4 8 marae i 2N3707 di 40802 188 BC148 3 3 BSX20 nd ENGLEFIELD CABINET KITS 1 2N3708 AC107 BC149 3 8 BY164 T 1N5054 j 2N3709 3j ACI26 6 8 BC153 10 BY238 ge Buildit 2 12 or 25 25 18940 l 9N3710 3 6 AC127 8j BC154 11 C106B1 14 8 2N696 0 8 2N3711 3 11 ACI28 6 BC157 8 9 MC140 5 2N697 5 6 2N3731 94 ACI76 ll BC158 3 6 MJ480 21 2N706 2 9 2N3794 8 8 ACY22 8 8 BC159 3 9 MJ481 27 2N1302 4j 2N3819 8 6 ACY40 4 BC167 2 8 MJ491 30 2N1303 4 2N3820 25 68 ACY41 5 BC168 2 3 MPF102 1 8 E 2N1304 4 6 2N3904 7 6 AD142 14 3 BC169 2 8 NKT403 15 6 Stereo amplifier in modular kit form 12 watts per channel 2N1305 4 6 2N3906 76 AD149 17 8 BC177 6 3 NKT405 15 38 9 25 watts 258 15 Cabinet kit only 8 These 2N1306 6 9 2N4058 5 8 AD161 AD162 BC178 5 8
93. seia ministry by Airmec sto T o NO TRIO JR 500SE 10 80 Metre CRIVER with speaker and mains P S U CORCA 3 Frequency coverage 200 250V A C Bupplie Receiver 69 10 0 212 IN STOCK ge 20 80 poa AM E M C W FM Incor dition 2210 o RCA COMMUNICATIONS purates precision dial level meter precision j attenuator 1jV l00mY Operation from 12 Carriage 30 RECEIVERS AR88D volt D C or 0 110 200 250 volt A C Size iz Latest release by ministry BRAND NEW in original n LEES TR pup EA oe ae fons cases 110 2507 A C operation Frequency in 6 Bands 535 Ke s 32 Mc s continuous Output im teated 45 Carr 20 D celtic MARCONI v ie M 2 5 600 ohms I ti tal Alt SANYA E IT a Cas e at pct Bud D pedance 2 5 600 ohms Incorporating crystal filter EDDYSTONE VHF RECEIVERS Model 770R T 44 TF956 t i MI TT role SS FANADIS BEY variable selectivity etc 19 165 Mc s Excellent condition 150 Rome Porson RUSSIAN C1 16 DOUBLE LAFAYETTE PF 60 SOLID STATE VHF FM RECEIVER BEAM OSCILLOSCOPES D pjwatt to s watta A completely new transistorised receiver covering EN ut E Xe ET ELLE 5 MHz Pass Band Separate Yl Y2 ampli 20 Carr 10 152 174 Mc s Fully tunable or crystal controlled fiers Calibrated triggered sweep from sec iUt UNI to 100 milli seo em i Supplied complete with all accessories and instructions 87 Carr paid TE 16A Transistorised Signal Generator oranges 400kHz 30m Hz An ine
94. socket d Complete system comprises 5 5 amplifier Garrard 3000 or model 50 with 9TAHC diamond cartridge Pair E M I Owatt speakers twin tweeters and crossover with polished wood cabinets 18 x 11 x 7 Also plinth and cover CREDIT SALE FOR CALLERS O COMPLETE STEREO SYSTEM Rec Price 50 Rec ice 69 39 10 0 O AMPLIFIER ONLY 13 19 6 p p 7 6 O TEIO35 RECOMMENDED STEREO PHONES 39 6 BUILD THIS VHF FM TUNER 5 MULLARD TRANSISTORS 300 ke s BANDWIDTH PRINTED CIRCUIT HIGH FIDELITY REPRODUC TION MONO AND STEREO A popular VHF FM Tuner for quality and reception of mono and stereo There is no doubt about it VHF FM gives the REAL sound All parts sold separately PARTS TOTAL COST 6 19 6 p p 3 6 DECODER 5 19 6 FOR STEREO p p 3 ASK FOR BROCHURE No 3 New printed circuit design with full power output Fully tuneable on both MWILW bands 7 Mullard transistors Fitted Sin speaker Room filling power Easy to build with terrific results Two colour leather cloth cabinet with silvered front All local and continental stations Complete detailed instructions Total cost 6 19 6 p p 6 6 BUILD YOURSELF A QUALITY RADIO Ask for Leaflet No SINCLAIR EQUIPMENT PZ6 6 19 6 Z50 5 9 6 PZ8 5 19 6 SPECIAL OFFER Complete range of amplifiers and preamplifiers in stock All detailed in catalogue above Z30 75 each stereo 60 8 10 0
95. specially edited to facilitate individual home study You will learn in the comfort of your own home at your own speed The unique ICS teaching method embodies the teacher in the text it combines expert practical experience with clearly explained theoretical training Let ICS help you to develop your ambitions and ensure a successful future Invest in your own capabilities FILL IN AND POST THIS COUPON TODAY You will receive the FREE ICS Prospectus listing the examination and CS technical courses in radio television and electronics PLUS details of over 150 specialized subjects CS ee ee eee Te d am 50 C 41 PLEASE SEND FREE BOOK ON ut j l l ADDRESS m i OCCUPATION Mesma Sulit eae 1E ei AGES Lk re l i INTERNATIONAL CORRESPONDENCE SCHOOLS i ee n Dept 170 INTERTEXT HOUSE STEWARTS ROAD London SW8 M e 9 70 379 MONO TRANSISTOR AMPLIFIER A really high fidelity mon aural amplifler with perform istics to suit RE the most dia criminating listener 6 transistor circuit with integrated pre am bled on special prin ted sub panel AD161 AD162 operating in symmetrical complementary pair Output transformer coupled to 3 ohm and 15 ohm speaker Bockets Standard phono input sockets Full wave bridge rectifier power supply for AC mains 200 240v Controls Bass Treble Volume on off Function selector for PU
96. spheres and plates to the spark gap on the transmitter and to the ends of the receiver loop He was in fact using what we now call dipoles and towards the end of his experiments Hertz was able to resonate his transmitter and receiver to approximately the same wavelength The frequencies involved were in fact what we would now term v h f As if these incredible experiments were not enough Hertz then demonstrated the phenomenon of standing waves using a long cage of wires strongly resembling the present day Lecher wire system of measuring wavelength Using sheet metal reflectors and reflectors made of wire stretched on wooden frames Hertz showed that his Hertzian waves could be treated as light waves and bent or reflected at will Little did Hertz realise that he was really demonstrating the basic principle of radar Crown Copyright Science Museum London Collection of reflectors and resonators used by Hertz in his experiments 381 Since many modern v h f and u h f aerial systems strongly resemble the equipment used by Hertz in his famous experiments it would not be ungenerous if he were to be regarded as the father of v hf communication It is surely little enough reward for his name to be associated with the basic unit of frequency the cycle per second or Hertz Hz since he was the first to devise a method of measuring the fr quency or perhaps the wavelength of electro magnetic waves filobil
97. the use of 6 separate instruments st the same time The volume controls for each channel are located directly above the corresponding input sockets SENSITIVITIES AND INPUT IMPEDANCES Channels 1 and 2 4mY at 470K These 2 channels 4 inputs are suitable for microphone or guitars Channels 3 and 4 300mV at Im Suitable for most high output instruments gram tuner organ etc Input LIQUIDATED STOCK DANSETTE TOURISTE IVIK3 EXTRACTOR FAN A C mains 230 250v com plete with pull switch Size 6 x 6x din Price 27 6 plus 7 6 P amp P THE RELIANT Ta neni wolune ii SOLID STATE GENERAL PURPOSE AMPLIFIER SPECIFICATIONS Output 10 watts Output impedance 3 to 4 ohme Inputs l xtal mic 10mV Tone Controls Treble control range 12dB at 10KHz 2 gram radio 250mY Bass control range 13dB at 100Hz Frequency Response with tone controls central Minus 3dB points at 20Hz and 40KHz Signat to Noise Ratio better than 60dB Transistors 4 silicon Planar type and 3 Germanium ype Mains input 220 950V A C Size of chassis 10tin x 4 in x 21in For use with Std or L P records musical instrumenta all makes of pick ups and mikes Separate bass and treble lift con trol Two inputs with control fron gram and mike Built and ES mi sitet tested RELIANT Mk RELIANT Mk II As above less teak case In teak finished case 6 10 plus 7 6 P amp P 7 5 plus 7
98. to 20 KHz Output max 10 dB 10 K ohms Opera tion 290 240v A C Size 215mm x 150mm x 120mm Price 27 10 0 Carr 5 COMBINED AF RD iB Tum DEUS m a E EQUIPMENT Aap es ht nans sf SEND NOW ONLY 716 P amp P n FULL CURRENT RANGE OFFERED BRAND NEW AT FANTASTIC SAVINGS 1024 stereo 87 19 868 S8L72B 24 19 6 40 Mk 1I stereo 8 8 0 AP75 16 19 6 20925T C stereo 817 68 SL75 25 19 6 3000 stereo 9 19 6 SL7i 8227 19 68 SP25 Mk II 10 19 8 SL95Hh 37 10 0 SL55 11 12 6 A 70 11 11 19 6 SL63H 1418 8 401 25 0 0 Carriage 7 6 extra each item TEAK PLINTHS amp PERSPEX COVERS 1 For SP25 8L65 SUAS 3000 2025 T C 2025 1000 4 10 0 For AP75 8L75 SL95 25 19 6 Carriage 7 6 extra each type The Rits NOR giving fult details af a comprehensive range of HI Fi EQUIPMENT COMPONENTS TEST EQUIP MENT and COMMUNICATIONS Over 230 pages fully illus trated and detait ing thousands of items many at bargain prices FREE DISCOUNT COUPONS VALUE 1r i cue wc For SP25 etc to operate with lid in place 5 19 6 Full range of Carrard accessories available vat SPECIAL OFFERS RTC249 4 TRACK TAPE DECK Garrard SP25 fHted Goldring Britiah Made Q800 cartridge and wooden plinth Speeds 1j 3i Total list price 32 8 5 71 P 8 Marriot OUR Carr Heads 7 Teel price 19 15 0 70 nize Push But Plastic cover 25 ext
99. wadding mounting bolts wire etc are supplied you provide the cabinet to suit your needs Bin Bass Mid range speaker employing a powerful magnet assembly with diecast chassis and Flexiprene roll surround The Wharfedale Unit 3 speaker kit can be constructed by any body and with a Suitable cabi net will provide a highly sophisticated system giving true Hi Fi reproduction from 40 17 000Hz Impedance 4 8 ohms Max power handling 15W 11 19 6 each Si 20 per pair 5 UNIT 4 SPEAKER KIT 2 speakers t2in Bass and 3in Treble to give full range balanced reproduction Frequency response of 45 17 000Hz when housed in suitable cabinet Superior 4 element crossover unit ensures optimum performance from each speaker 16 each 30 per pair i5 5 10 UNIT 5 MONITOR SYSTEM KIT 3 speakers 12in Bass 5in M R unit lin Treble give clean smooth performance Frequency response of 40 20 000Hz when housed in suitable cabinet Unique mechanical electrical 6 element crossover unit Post 23 10 eac Pe 42 per pair is TTC HEADPHONES MODEL G Illl Yet another outstanding TTC product which gives you exceptional value plus super quality These stereo phones use two Jin low imp high flux density dynamic repro ducers Freq Res 25 15 000Hz Fitted with foam cushioned adjustable earpads for super listening comfort imp 8 ohms matching 16 ohms Max Input 0 5W Com plete with 36in shielded grey cable Pearl gr
100. 0 Raymond Peart of Worcestershire used his Spidola transistor receiver and 100ft long wire to log 6145 Deutsche Welle in English at 0500 0555 9650 ABC Australia in English at 0645 0915 9770 Austrian Radio in German at 0730 9833 Radio Budapest in German at 1330 21495 Radio Portugal in English at 1345 1430 Due to the ever increasing number of reporters to this column I will in the future only be able to use those reports which contain accurate details of frequency and time and the name of the station All reports should arrive at 58 Kensington Gardens Cranbrook Ilford Essex by the 17th of the month 359 THE AMATEUR BANDS David Gibson G3JDG OTS of interesting things happening this last month both on and off the Amateur Bands For the c w versus a m versus s s b addicts you ve got a nasty shock coming from the profes sionals At a recent conference in London a very strong case indeed was put up for double side band diminished carrier On tests carried out in the field a 6W d sb transmitter consistently outdistanced a 25W am transmission The police force are seriously considering using d s b and data transmis sions at around 2 4 kilobits second Yet another seminar discussed interference One point which came out here was that of earthing lt was agreed that any interference problem and earthing system was very much an individual thing and that no one simple solution or set of rules existed Makes yo
101. 0 each plus 1 6 p p SCOOP PURCHASE OF BRAND NEW CARBON RESIS TORS 10 tolerance amp 4 watt Perferred values in packets of 10 Our price 10 per 100 18 per 200 27 per 300 500 at 42 8 Our selection p p 1 6 per 100 and 6d per extra 100 TRIMMER BARGAINS These are 10PF sub min air spaced trimmers on board with min wire ended Xtal Brand new No details Contents 12 trimmers some ceramic caps Xtal frequency IRD overtone 249 mc s 250 Mc s 255 Mc s No choice Trimmers without Xtal 12 per doz plus 3 6 p p Trimmers with Xtal 15 per doz plus 3 6 p p Also 20 PF min brand new air spaced 10 per doz plua 3 6 p p SIGNAL GENERATORS OSCILLATOR No 2 Size 12in x 8 in x 9in Ideal for VHF work 20 80 Mc s Functions are AM CW Deviation up to 40 Kc a RF meter Measuring levels RF output 1 microvolt to 100 microvolts set Mod set carrier controls Good condition with accessories 230V AC 12V DC 20 0 0 plus 15 p p TF 144 G Signal Generators 85 Kejs to 25 Mc s Good condition and complete with accessories 222 0 0 plus 30 p p RF Thermo Couple Meters New and boxed 0 1 amp 2in diameter 17 6 plus 4 p p MAINS MOTOR 250 volt AC 1 40th H P at 1 600 R P M Ex WD type Blize Gin x 4in Tested and in good condition 35 plus 7 6 p p TELESCOPIC MASTS New condition 20ft closes to oft Qin 90 carriage 15 34ft closes to 5ft 9in 120 carr 15 Used condition 20ft 70
102. 0 fitted Goldring CS90 high com Designed for optimum performance with HF105DL 10 10W gns HFl26D 12 15W 0 15 0 pliance ceramic Stereo Mono cart any crystal or ceramic Gram P U cart ridge Radio tuner Tape recorder Mike etc X 3 separate switched input sockets on each channel jk Separate Bass and Treble controla Slide Bwitch for mono use Speaker Output 3 15 ohins y For 200 950v A C mains jk Frequency Response 20 20 000 c p s 2dB w Harmonic Distortion 0 3 at 1000 cps Hum and Noise 70dB w Sensitivities 1 50 mV 2 400 mV 3 100 mV Output rating 1 H F M jk Handsome finish Facia plate and Knobs Com plete kit of parts with full wiring diagrama amp instructlons Car 7 FACTORY BUILT with 12 mth gntee 17 Gns or Deposit 31 Gr 9 3 and 9 monthly payments 38 10 Total 18 Gns Ds Or in Teak or Afrormosia veneer housing 20 Gns Dep 3 Gns and 9 monthly payments 46 8 Total 23 Gns ridge with diamond stylus Carr 9 6 24 ci Garrard 2025 Auto Unit RPSC fitted Garrard GCS 23 hen Cartridge with diamond tip linth amp Cover as RP C carr 9 6 15 Gns Other types available with Mag netlo cartridges and with alternative design plinths Io numm l Limited Number of CLEARANCE LINES in leading makes of Hi Fi equipment at Branches only HIGH FIDELITY LOUDSPEAKER UNITS Cabinets latest style Satin Teak or Afrormosia veneer Acouatically lined or filled acoustic damping Ported where appropr
103. 00 812 19 6 Post 5 6 RECORD PLAYER PORTABLE CABINET 75 j Space for amplifier and autochanger Post 5 ROS DE LUXE 3 WATT AMPLIFIER Ready made and tested A 2 stage unit using triode pentode valve giving 8 watis output Tone and volume controis Isolated mains transformer With knobs loudspeaker and valves ECL82 EZ80 Frequenoy response 50 12 000 cpa 8 Sensitivity 200mV Post 5 6 R 0 8 TEAK WOOD BASE Ready cnt ont for Mounting State player make and model R C 8 PLASTIC COVERS FOR ABOVE 77 6 BASE Durable tinted plastic attractive appearance EMI PICK UP ARM Complete with mono cartridge 20 6 EMI JUNIOR 4 SPEED RECORD PLAYER Mains operated motor turntable and pick up 59 6 complete Post 5 8 HI FI PICK UP CARTRIDGES GP94 55 GP93 45 GPO1 30 GP67 19 0 ACOS L P only 10 6 All standard fixing complete with stylus CRYSTAL MIKE INSERTS 14 dia 6 6 ACOS 12 dial 12 8 BM3 1 dia 9 6 Portable mini p a system Many uses ides for Parties or as amp Baby Alarm Intercom Tele phone or Record Player AmPHfler etc Attractive rexine covered cabinet size 12 x 9 x 4in with powertul 7 x 4in speaker and four transistor one watt 3 power amplifier Uses PPO baitery Brand new in Makers carton with full maker s guarantee World famous make Only Re 5i j en WEYRAD P50 TRANSISTOR COILS RA2W Ferrite Aerial 12 6 Spare Cores 6d Osc P50 1A0 5 4 Driver Trans
104. 01 648 4884 Rx gt Za gt x 2 i Gee e lt SW ar NS S SESS c E D RA 7 7 y 7 nar 7 A US YANG LV USN YS vg SAN PD Av AN NG A ASIAN Yin WIN ISS A mS ZEN ININ ON THE MONTHLY NEWS FOR DX LISTENERS THIS month seems to have been a bumper one for Broadcast Bands listeners and I have been swamped with reports and letters C R S Stacey of Tunbridge Wells who regularly uses his Lafayette HA 700 and Joystick to send in excellent reports like the following 5047 Radio Togo Eng news at 1950 15165 Syria Overseas Service English 1930 15300 NHK Japan Eng 1800 1815 15435 DW Kigali relay in Amharic 1415 15440 FEBC Philippines in English at 1530 Glyn Morgan of Tredegar has an impressive line up of equipment including a Lafayette HA 230 an Eddystone EC10 and a Hallicrafters SX130 and a Soft long wire aerial This equipment enabled him to send in a report which included 3232 R Brazzaville Congo in French at 2205 3376 CRORP Angola English music at 2205 4765 R TV Congolaise French at 2155 4815 Upper Volta talk in French at 2220 4835 R Mali play in French at 2210 4850 R Mauritania at 2050 4880 Kinshasa Congo African music at 2245 4885 Nairobi Kenya pop music at 1845 4905 R Relogio Brazil Port at 2145 4915 Nairobi Kenya often heard at 1900 4926 R Ecuatorial Guinea Spanish at 2140 4940 R Abidjan Ivory Coast music at 2225 4976 Kampala
105. 078 Triple Core P V C covered circular nor mally sold at 1 6 yd Our price 100 yd coll 8 19 8 Post and Insurance 6 6 6 12 or 24 VOLT SOLENOID For energising Reed Switches etc 4 6 cach please state voltage RADIO STETHOSCOPE Easiest way to fault find traces algnal from aerlal to speaker when signal stopa you ve found the fault Use it on Radio TV w 9 amplifier anything com plete kits comprises two special translators and all parte jnolu ding probe tube and crystal earplece 29 6 twin atethoset instead of earpiece 11 extra post and ins 2 9 TELESCOPIC AERIAL ue for portable car radio E it or transmitter Chrome pla p d ted six sections extends from 7i to 47in Hole in bottom for GBA screw 7 0 KNUCKLED MODEL FOR P M 9 8 BATTERY OPERATED TAPE DECK With Capstan control This unit is extremely well made and ineas ures approx 6x5x2 in deep Has three Piano key type con trols for Record Play back and Rewind Motor is a Rpecial heavy duty type in tended for operation off 4 6 volta Supplied complete with 2 spouls ready to install Record Replayhead is the sensitive M4 type intended for use with transistor amplifier Price 79 8 Post and insurance 4 6 INTEGRATED CIRCUIT BARGAIN A parcel of integrated circuits made by the famous Plessey Company once in a lifetime offer of Micro electronic devices well below cost of manufacture The pa
106. 10 250 1 000 2 000 v A C 0 23 12 5 10 50 250 1 000 5 000v D C 0 50 A 110 100 500m A 10 amp D C 02K 200K 20 MEG OHM 15 P amp P fe LAFEYETTE 57 Range Super 50k 2 volt Multi meter D C volta 12 mY 000V A C volts 1 5Y 1000V D C current 2534A 10 amp Ohms f IOineg QAB 20to 8 dB Overload pratection 12 10 0 Carr 3 st Mirror scale ov erload proter E AVO CT471A MULTIMETER Battery operated Sensitivity 100m Jv Measures AC DC Voltages 12mV to 1 AC DC Current 1 u to 1 2 Amp Resistance 12 ohm to 120 mO HF VHF UHF Voltage with multiplier 4v to 400v up to 50 Me s dO V to 4v upto 1 000 Mc s Offered in perfect condition 55 each Carr 10 fully transistoriseil 2004 TRANSISTORISED TWO WAY TELEPHONE INTERCOM Operative over atnazlngly long distancex Reparate call and press to talk buttons wire connection 1000 s of applications Beautifully fin ished In ebony Supplied complete with hatleries and wall brackets 6 19 6 P amp P 3 n SINCLAIR EQUIPMENT Project 60 Package offers x Z30 amplifier sterea 60 pre amp PZ5 power supply 19 0 0 Carr 7 6 Or with PZs power m supply 2 Carr 7 6 2 x 250 amplifier stereo fi pre amp PZ8 power sorely 821 10 0 Carr 1 6 ranstoriner jur PZ8 59 6 extra Add to auy of the above 24 17 6 for active filter unit and 18 for a pair of Q16 speakers
107. 10 at 1930 with a programme in English MONACO Radio Monte Carlo is now broadcast ing twelve hours a day in Italian on 1466 and the shortwave frequencies of 6035 and 7135 The latter frequency provides very good reception Philip Batt of Littleborough in Lancashire has a PCR3 receiver and a 60ft long wire antenna which enabled him to hear the following stations 4920 YVKR Caracas Venezuela 0600 15060 Radio Peking in English at 0930 15140 Radio Vilnius Lithuania sign off at 2300 15160 ABC Australia in English to Asia at 0700 15275 R Afghanistan in English at 1800 15370 R Tamoio and Tupi Rio at 2200 17785 Tentative logging of Radio New Zealand with English news at 0700 17855 Radio Japan with English news at 0800 21505 R Accra Ghana in English at 1554 V P Hill of Cwmbran owns a 5 valve domestic superhet and an 80ft long wire and his log in cluded 9560 ABC Australia in English at 0645 15160 Voice of Turkey at 2220 17445 Radio Havana Cuba at 2042 17448 WINB United States of America at 1956 17650 Trans World Radio Bonaire at 2155 Stephen Wainwright of St Helens used his Sky rover Mark II receiver and 100ft long wire to hear the following 9465 R Pakistan in English at 1945 2030 11815 AA Neth Antilles in English at 0030 130 15013 Voice of Vietnam in English at 2000 2030 17740 VOA Monrovia Liberia in English at 0800 21690 Windward Islands Broadcasting Service Grenada in English from 1945 220
108. 108 ADIS 7 CRS1 30 10 ZL range EBF89 6 ppoo 6 PCLSO 9 OC28 8 OCIT 6 Fl00 12e NFS Lg GERI dS ible ae ECC81 i Pro5 7j PFL200 14 a CHRO fS pesas ECC82 5 9 ypysoo 17 PL36 10 9 ie ee ECC83 5 6 EM31 5 PL81 8 9 QQVO3 10 VR150 30 6 5R4GY 6AB7G j ECO84 6 gwao 7 8 PLa2 8 UAF42 Z759 35 5U4G 5 6 6AT6 4 6 8EAB 11 ECCI89 9 9 gv5i s PLSo0 14 9 QQVO6 40A UBF89 7 Z900T 12 5Y3GT 6 6AX5GTI3 6F33 90 ECF80 6 6 yval 7 PLs04 16 100 UCF80 10 IL4 9 6 5Z4GT 12 6B7 5 6 6H6M 3j ECF83 18 6 pyss aig PX4 14 R19 17 6 UCH8l 6 6 I84 5 GAB 7 4 6BA6 4 6 615 7j ECF801 12 6 EZ41 8 6 pxos 30 8TV280 40 UCL82 7 6 I85 4 6 6AC7 3 6BE6 5 6J8GT 5 ECF802 126 amp z80 5 PYS3 12 80 UCL83 12 IT4 3 6AH6 11 66BG6G 11 676 3 6 ECH35 lll wza 5 8TV280 80 UF41 10 IX2A 7 6 6AK5 5 6BJ6 8 8 637G 5 ECH42 1l3 G234 106 EX60 6 6 180 UF80 7 3 1X2B 7 6 6AK8 6 6BQ7A 6 9 677M 8j ECH81 5 9 kres 27 g PY81 5 8 TT21 51 UF89 6 8344 4 6AL5 23 6BR7 16 6K6GT 8 ECH83 8 6 kras 33 PY82 5 6 U25 14 e UL4l 12 3D6 3 6AL5W 7 6BW6 16 6K7 6 6 ECH84 7 6 w s 95 Pyss 7 U26 14 6 ULS4 6 6 3Q4 7 6 64M6 2 6BW7 13 8K7G 9j ECH200 12 6 042 6 PY88 76 U27 8 UU5 7 384 6 89 6AN8 10 6C4 5 9 6K8G 4 ECL80 9 O ln iva 14 UY4l1 8 6 3v4 8 6AQ5 6 6C6 4j 6K8GT 7 3 ECL82 6 6 0B2 9 j PY80 9 6 0301 11 6 UYSo 5 9 5B254M 36 6AQ5W 9 6
109. 13 6 6 10 10 13 o ooo Oo o y amp oooOuUomcoooOooooooo m 109 0 284 0 243 0 85 19 133 0 167 0 99 19 72 19 29 19 24 19 24 19 32 19 37 19 79 19 29 19 34 19 39 19 47 19 69 19 COMET Hi Fi DISCOUNT WAREHOUSES Reservoir Road Clough Road Hull HU6 7QD Tel 407906 also at 68a Armley Rd Artist St Leeds LSI2 2EF Tel 32055 ao Oo A aneno ERRA aoo eGA o O OODORARRLULARNRGAROARANOOA DECKS AND TAPE o nas AG q ooo PAGO omOeoon ooo 383 BENTLEY ACOUSTIC CORPORATION LTD 38 CHALCOT ROAD CHALK FARM LONDON N W I THE VALVE SPECIALISTS Telephone 01 722 9090 OA 5 9 6B8G 2 6 6Q7 8 8 12AX7 4 6 30LI7 15 6 AC2PEN OB 6j 6BAG 4 6 6Q7G 6 124 Y7 9 9 30P4 12 DD 19 6 OZ4 4 6 6BE6 4 9 6R 11 12BA6 6 30PAMR ACGPENT 6 1A3 4 6 6BH6 7 6 6R7G 7 I9BE6 5 9 17 6 AC PEN 5 1A5 5 6BI6 8 6 6SA7GT 7 12BH7 6 30P12 13 8 19 6 LA7GT 7 8 6BQ5 4 9 6SA7M 7 12ELl 17 30P19 1g AC PEN 7 1C5 4 9 6BQ7A 7 68CiGT 6 6 1257GT 6 6 30PL1 13 9 19 6 1D5 7 6 6BR7 15 9 ASQ7GT 6 12K5 10 30PL13 15 6 AC T H110 1D6 9 6 8BR8 12 6 6817 8 I2K7QT 8 8 30PLI4 15 AC TP 19 6 IFDI 6 6 6587 25 88J7 8 8 12Q7GT 5 30PL15 15 AC VP210 6 1FD9 4 8 8BW6 14 3 68K7GT 4 6 I2SATGT 13543 10 AL60 15 6 186 6 8BW7 18 6G8N7G T 4 6 8 30AD 18 ARP2 7 1H5GT 7
110. 2 9 6 BFY20 12 6 0C203 500 2 6 any one type EST 189 98701 8 6 BFY50 5 OC204 28702 11 BFY51 4 6 0C 05 deias a eN oca 76 Dept 171 Intertext House Stewart Road London S W 8 l MES 9 8 as ve Rats Mullard Please send me the ICS prospectus free and without obligation i MC ge um He poe state Subject or Exam a1 2 ester dst SE OVER e Leito c Dans cae oce e REC AAY12 5 IBLYIL 29 6 0RP60 500 3 500 4 Bec e emn MU tere IT a LT eh een YET PLEASE NOTE MINIMUM ORDER SHOULD BE 0 i i Quantity Prices 100 Phone 01 Send for your free copy of 1970 List i NAME 7230401 Ex 4 All listed devices are No 36 of over 1000 devices today b sk Ead U ra uA X w abbas Pu Br from stock at time of going to press pacc i oho e IPS i ADDRESS MT SETTE ESTE Jearanpondadadbasoaotosaaaadtnn Te i pr SE is Bes rtiie A dan 1597 on 25 any one type DX few OM EUIS RN AUR IRR 9 70 HENRY S RADIO 392 A TWO TONE MINO il A S CARPENTER G3T YJ sented here being rather a practical presentation of a transistorised device very useful in the modern amateur radio station The device may also be used in other ways as will be mentioned later It is easily copied and can be constructed in a few hours and will cost approximately 35s even if every item has to be purchased As the illustration shows the finalised unit is attractive in appearance and ruggedly built T senta is nothing unique in the circuitry pre
111. 24 3 6 25 99 2 9 100 2 3 BY 127 4 Mullard Plastic HV rectifier 800 piv 1 amp similar BY100 etc 25 3 3 100 3 a Tices quoted are current at time of going to press E amp OE and may be subject to variation withou notice lItems listed not in current production will be withdrawn when stocks advertised are sold Address your order to Semiconductors offered carry full Manufacturers guarantee where applicable Data sheets will be i supplied on request 1 per copy Price breaks apply at 25 amp 100 Please contact Sales Dept for L S T ELECTRONIC COMPONENTS LTD Price amp Availability Terms of Business Retail Mail orders cash with order only please Trade 7 COPTFOLD ROAD BRENTWOOD ESSEX Nett Monthly Account on receipt of gatistactory pero nees Die RATER ponds Quoted ex stock are normally despatched within one working day by first class post Export orders and enquiries par ticularly welcome Cables LESTROCO BRENTWOOD Post amp Packing allow 1 per order inland Phone Brentwood 226470 1 QI E 407 Head Office and Warehouse 444 WESTBOURNE GROVE Tel PARK 5641 2 3 408 Z amp AERO SERVICES LTD meshp LONDON W2 Please send all correspondence and Mail Orders to the Head Office LONDON W1 When sending cash with order please include 2 6 in for postage and handling
112. 25 20 50 100 200mF 15V 2 500 1000mF 12V 3 6 2000mF 25V 7 CERAMIC 1pF to 0 01 mF 9d Silver Mica 2 to 5000pF 9d PAPER 350V 0 1 8d 0 5 2 6 1mF 3 2mF 150V 3 500V 0 001 to 0 05 9d 0 1 1 0 25 1 6 0 47 5 1 000V 0 001 0 0022 0 0047 0 01 0 02 1 8 0 047 0 1 2 8 SILVER MICA Close tolerance 1 2 9 500pF 1 6 580 2 200 pF 2 2 700 5 800pF 4 6 BOODF 0 01 mtd 6 each TWIN GANG p 0 9208pF 176pF ll Slow motion drive 85 365 with 25 25pF 11 600pF slow motion standard 9 small 3 gang 500pF 22 SHORT WAVE Single 25pF 11 CHROME TELESCOPIC AERIAL 23in 5 cp Ds Solid dielectric 100pF 300pF 500pF 7 each RIMMERS Compression 30 50 70pF Us pE 150pF ie 950pF 1 8 600PF 750pF 2 1000 RECTIFIERS CONTACT COOLED SE uec 7 6 85mA 9 6 SILICON BYZ13 8 BY100 10 Full wave Bridge Rectiflers 75mA 10 150mA 19 6 EX GOVERNMENT RECTIFIERS 250v 200mA 6 NEON PANEL INDICATORS 250V AC DC Red Amber 4 RESISTORS Preferred values 10 ohms to 10 meg 3 w w 1 w 20 8d 1j w 8d 2 w 1 w 10 6d HIGH STABILITY bow 19 10 ohms to 10 meg 2 Ditto 5 Preterred values 10 ohms to 22 meg Bd WIRE WOUND RESISTORS 5 watt 10 watt 15 watt 10 ohms to 100K 2 each 2 wati 1 ohm to 8 2 ohms 2 Q MAX CHASSIS CUTTER Complete amp die a punch an Ailen screw and key lin 18 tin 17 6 1fin 19 6 lin 24 2 4 44 3 fin 16 lin 19 6 1ijin
113. 250v LOOmA 6 87 3 5a 27 9 250 0 250v 100mA 6 37 2a 6 3v Ja 28 9 e 350 0 350v 80n1A 6 3v 28 0 0 6 3v 2a 29 11 250 0 250v 100A 6 3v 4a 0 5 6 3v 3a 39 9 4 9 300 0 300y 100mA 6 3v 4a 0 5 6 3v 3a 99 9 300 0 300v 130mA 6 3v 4a 0 5 6 3v la iz LES 13 x 8 8 10 Watt 16 000 lines 3 or 15 ohms Carr 7 6 Polanie for Mullard 510 Amplifier 46 8 4 350 0 350v 100mA 6 3v 4a 0 5 6 3v 3a 39 9 emer te Muay 8 19 9 350 0 350v 150m 6 3v 4a 0 0 6 3v 3a 46 11 inc DS FILAMENT or TRANSISTOR POWER PACE Carr 8 9 Types 6 3v 1 5a 8 9 6 3v 2a 9 9 6 3v 3a 13 9 6 37 6a 29 90 19v la 9 1 12v 3a or 24v R S C BASS REGENT 1 5a 23 9 0 9 18v 14a 19 11 0 19 25 42v 2a 31 9 CHARGER TRANSFORMERS 0 9 15v 11a 18 9 50 W ATT AM p LI Fi ER 21a 19 11 3a 21 11 da 25 11 6a 29 9 8a 36 9 OHIO 150 200 390 350 60 80 atto 19 0 or e 20v 280 25Q0v 20 80 wa iO x A powerful high 150 watts 33 6 250 watts 49 9 500 watts 105 quality all purpose OUTPUT TRANSFORMERS unit for lead rhythm Standard Pentode 2 000 Q or 7 000Qto8Q 8 9 bass guitar vocalists Push Pull 8 watts EL84 to 3 Q orl Q 14 9 En gram radio tape m uy welts 6V6 ECL86 to 3 5 8 or TM Si Peak Output rating Push Pull EL84 to 3 or 15 Q 10 12 watts 23 9 X Two extra heavy duty 12in Loudspeakers Push Pull Ultra Linear for Mullard 510 etc 39 9 X Four Jac
114. 3 4 3 AFIS6W 9 BCY70 310 BSY29 5i NKT151 6 NKT281 5 OCH 4 6 40314 73 2N1308 6 2N4291 3 15113 4 6 AF186G gj BCY71 7 8 BSY32 5j NKT153 6 NKT301 f8 OC42 4 6 40315 73 2N1309 6 3 2N4292 3 15130 2 AF239 76 BCYT2 BSY36 5 NKT154 6 NKT302 12 5 OC43 4 6 40316 9 3 2N1613 4 5 2N4871 6 9 18131 2 6 AFY19 22 6 BCYB87 BSY37 5 NKT161 6 NKT303 OC4 3 40317 73 2N1711 5 25104 12 6 18132 3 AFZ11 8 BCZ1 B 8 4 NKT1E 6 KT304 OC4 40319 0 9 N 14 j 128 iE 420E NEWS NEWS NEWS NEWS BCI 07 8 9 2 9 2N38 9 7 SILICON RECTI FI ERS L S 7 Electronic Components Limited are proud to announce their NPN PI t ist official appointment by Newmarket Transistors Ltd All Newmarket C1 anam adsis ors Texas FET 1 Amp Miniature Moulded Junclion products now available at Industrial User prices All R C A Semi 7 Rectifiers conductors and Integrated circuits now also avaliable from L S T at Industrial User prices Many Mullard General Electric Texas types also ex stock at LST at Industrial User Prices and better And what s more our Retali catalogue is free to all Iskra resistors Mullard Capacitors Veroboard Repanco coils and other mlsc components stocked in large quantities Official International Rectifier Semiconductor Centre stockists INTEGRATED CIRCUITS Some R C A Linear types CA3005 23 6 CA3022 26 CA3041 21 9 CA3011 14 9 CA3023 25 3 CA3042 21 9 CA3012 CA3026
115. 3 5 9 UL4 10 6 VRI5O 6 EBCAL 6 6 EF4L 10 GZ33 12 6 PCCHo 9 6 PYSR 6 9 UL46 12 6 VT6LA 7 EBC90 4 EF4 3 6 Gz34 10 PUC18910 6 PY301 12 8 ULS4 6 6 VUL 7 3 EBC9L 6 EF51 12 61GZ37 14 6 PCF80 6 6 PY500 91 6 UMsO 6 6 VU120 12 EBFSO 6 0 EF73 6 8 HABC808 6 PCF82 6 3 PY800 7 6 URIC 10 6 VU 1204A12 EBFS3 8 EFRO 4 8 HL23DD5 PCF84 8 PYsO01 6 8 UU5 T7 VvU133 7 EBFSS 6 3 EFS83 9 6 HLAIDD PCF86 12 9 PZ30 9 6 UUS 14j Wis 86 9 EBL 12 EF85 5 8 19 6 PCF20013 8 QQVO3 10 UUs 26 WiOL 26 2 EC53 12 6 EF86 6 3 HL42DD9 PCF801 7 24 j UU12 4 9 W107 8j ECA 10 EFS 5 HN309 27 4 PCF802 9 Q875 20 UYIN 9 W729 12 EC70 4 9 EF9 3 8 HVR2 10 6 PCF80514 12 8 UY 9 6 X41 10 ECs6 12 6 EF 2 6 HVR2A10 8 PCF80611 6 Q8150 15 UY41 7 6 X61 5 9 EC88 12 EF97 10 1W3 5 6 PCF80814 6 12 6 UY85 5 9 X5 10 ECo2 6 6 EF9 10 8 1W4 350 5 6 PCH 0012 8 QVO4 7 12 6 UJO 9 X66 10 ECC31 15 6 EFI8s 6 1W4 500 8 j PCL82 7 3 RIO 15 U12 14 7 6 X101 30 6 ECC33 4 6 EFIS4 6 K T2 5 PCL83 10 Ril 19 6 UIs 15 XE3 25 ECC33 81 6 EFP60 10 KTR 34 6 PCL84 7 6 R16 34 11 U17 5 XFY12 9 6 ECC40 11 EH90 7 6 KT4l 19 6 PCL805 80 R17 17 6 U18 20 10 XH 5 9 6 ECCHI 3 9 ELa 3 8 KT4i 90 9 RIX 10 Ul19 34 6 Z329 18 ECC82 EL34 10 6 KT63 5 PCLs6 8 6 R19 7 6 U22 7 9 2759 50
116. 34ft 80 carr 15 Base for same 20 carr 7 6 New toggle switches 12 6 dozen post and packing 2 6 New lengths 50ft Coaral cable 70 ohms coax plugs each end price 20 each post and packing 2 6 Magnetic Transducers new price 7 6 post and packing 2 New small fuse boxes 250 volts 15 amps 17 6 each post and packing 3 Meters moving coll ex equipment good condition 100Ma 500Ma Also 15 amp DC 20 amp DC 40 amp DC All at 10 post and packing 5 A H THACKER Radio Dept HIGH STREET CHESLYN HAY Nr Walsall Staffs 362 per range full wave ear Piece etc etc finger tiDs switching tc and medium imp inputs Drives your 12 volt relay full instructions 42 6 Ready built tested and 62 6 plus 2 6 P P METRONOME UNIT Variable beat while you play and keep in time pocket size with personal mini earphone kit form 27 6 post paid Ready built in an attractive black and white polythene case 37 6 post paid MORSE OSCILLATOR PC board tran sistors high stab components battery carrier Adjustable tone key Drives phones or speaker 17 6 post paid Ready built in Similar case as above 25 post paid STRAIGHT FROM THE PRESS Latest Muliard manual Audio Amps FM tuners Stereo decoder Receiver circuits Hi Fi Tape 32 6 post paid JUST ARRIVED IN STOCK Texas tran sistors Complementary symmetty NPN PNP output 6 6 post paid Free lists with ever order Fc
117. 350 pages x EQUIPMENT MODULES SPECIAL OFFERS ETC ETC Everything for tha constructor Complete with 0 value discount voucher for use with purchase Price 7 6 p p 2 WHY NOT SEND AWAY TODAY NE 25watt and 9 watt RMS SILICON AMPLIFIERS LOOK AT THE SPECIFICATIONS 0 3 Distortion at full power O idb lic s to 40kc s at full power O Response Idb lIc s to 100kc s PA25 IO Silicon Thyristors Differential input 25watts rms into Bohms 700mV input Size only 5 x 3 x 2 4 hole fixing Supplied with edge connector and harness PA5O I2 Transistor Version 50watt rms into 3 to 4ohms MU442 Power supply for one or two PA25 or one PASO O PA25 7 10 0 O PASO 9 10 0 O MU442 6 NEW STEREO FET SELF POWERED PREAMPLIFIER MODEL FETIS4 Inputs for mag Pickup Tuner Aux Tape in and out Response 20 c s to 30kc s Output adjustable up to volt Mains operated stabilised supply Slim design Size 12 x 51 x IH Price 16 10 0 NO SOLDERING JUST PLUG CONNECTORS FOUR ELECTRONICS CENTRE YOU CAN SAVE 25 tran new GARRARD Post 7 6 COMPLETE LIST FREE ON REQUEST AND GOLDRING SP25mkll 11 9 6 AP75 16 19 6 SL65B 14 19 6 SL72B 25 GL69 22 Above with Sonotone 9tahe diam Deke Add 2 with magnetic add 70 with Goldring G800 add 7 10 0 Also Fitted with 9tahc V diamond 2025TC 9 15 0 3000LM 9 15 0 Plinths Covers Standard 99 6 p p 4 6 De luxe 8 10 0 p p
118. 4 7 6 16 l 8 7 6 6 O 4 5 10 S5 STEREO TAPE DECKS AND RECORDERS AKAI 4000D AKAI 1710W E AKAI ITIOL AKAI 50D AKAI 1800 SD _ REVOX 1104 PHILIPS 4404 PHILIPS 4407 PHILIPS 4408 SANYO MR 801 SANYO MR 929 SANYO MR 939 SANYO MR 800 om TELETON FXB 570D i SHARP RD 712 UHER 4200L UHER 4400L SME 3012 with S2 shell GOLDRING L75 Pi GOLDRING L69 NEAT G30 e NEAT G30 B STEREO HEADPHONES AKAI ASE9SE SANSUI SS2 SANSUI SS20 TELETON SH30 D SHARP HPIOO GARRARD SP25 Mk II complete with De Luxe piinth and per spex cover ready wired to 5 pin din lug sd p e GARRARD AP 75 com plete with De Luxe plinth and perspex cover ready wired to 5 pin din plug GOLDRING GL75 with goldring plinth and hinged perspex cover ready fitted with Goldring 800E cart ridge ready wired to 5 pin din or phono plug E s o 87 109 109 130 199 204 80 103 136 79 100 110 89 52 75 162 162 hoOoooo0gO0ouuououvooo 90000000004h4000h000 TRANSCRIPTION ARMS SME 3009 with S2 shell 3 6 33 5 12 10 9 5 11 14 13 I8 M oO OWw 6 16 7 14 16 10 4 10 5 17 vx00ono 21 ts O o 33 15 67 19 10 74 89 89 109 165 O 184 67 87 O 110 O 67 86 O 91 75 0 43 60 0 130 O
119. 4 9 DISCOUNT Quantities of differ E ent 1N4000 series may be combined to qualify for the quantity discount prices quoted example 10 1N4001 1 5 10 1N4002 1 10 5 1N4007 3 4 25 total pieces In the event of any 1N4000 series going temporarily out of stock we reserve the right to send higher voltage types at no extra charge 1000 amp over prices on application OCP 71 19 6 Mullard Phototransistor 25 17 3 100 14 9 2N3055 15 115 watt silicon power transistor 25 13 1004 11 IRC20 7J Int Rectifier thyristor 200 piv 1 2amp similar C106B1 254 6 100 5 NES60B PHASE LOCKED LOOP The Phase locked loop is a circuit concept similar to a receiver in that one signal can be selected from many and information derived from the signal a with out tuned circuits A complete system in one 16 lead DIL package The NE560B PLL costs 12 0 10d in small quantities We don t expect you lo pay that without knowing what the PLL can do write now for free data 2N2926 2j NPN Planar transistors 25 1 8 100 1 6 ZENER DIODES 400m 10c GLASS CASE TEXAS Mfr 182036 3 6 volt 1S2082 8 2 volt 182039 3 9 volt 182100 10 volt 192043 4 3 volt 152110 11 volt 152047 4 7 volt 152120 12 volt 152056 5 6 volt 152160 16 volt 152062 6 2 volt 152180 18 volt 182068 6 8 volt 182270 27 volt 182075 7 5 volt 152300 30 volt PRICES 1
120. 4000P The dot identifies pin 1 the numbering going clockwise Finally the device is used in a completely transformerless circuit enabling a degree of compact ness to be achieved previously unobtainable in home built equipment In use the slightly higher noise and distortion figures are not significantly reflected in the output sound since in the type of equipment for which this unit is intended quality is inevitably loudspeaker limited and there is no advantage to be attained by incorporating more expensive semi conductor complements Circuit Now for a brief consideration of the circuit itself Fig 1 It is a six transistor unit with Tri acting as a stabilising element across the input and therefore controlling all stages of the direct coupled circuit The preamplifier transistor Tr2 is in an orthodox common emitter configuration and biased by d c feedback from the output stage of the circuit shunted as mentioned already by the regulator Trl which however does not affect the signal appearing at the base of Tr2 since the collector circuit of a transistor has a high impedance to applied signals It will be noted also that there is also a frequency dependent element the 0 0034F capacitor in this negative feedback loop to determine the frequency response of the complete amplifier Fig 2 The driver transistors Tr3 and Tr5 are a com plementary pair as indicated by the direction 377 indications on the emitter sy
121. 403 ZB TRANSISTORS SYNCHROSCOPE TYPE C1 5 Quantity prices quoted on request IN TEGRATED CIRC UIT 2NA04 3 6 92N3 07 4j BCY31 5 INAI 3 6 N3 00 3 5 BCY33 bf AMPLIFIERS 2N412 3 6 N3710 3 Roe we ME Mor REST ae ee 8 10 CA3000 Rl awpiifier IDOmers bandwidth 7f pet pita CIS vr BCZI 1 7 8 CA3012 Wide Ban Amplifier for EF applications 22 ANDE Hr ACI 5 86 BD191 18j CA3020 550mW Audio Amplitier a 80 ms v AIR x BCi 3 25 CA3036 Two super alpha pairs for stereo pick up I na Jor g po HyAtenIH P s 3h PORE yn NI 2 CA3052 Latest addition to RCA range Four in ane 2 N15 4 9 ACI53 5j BFI8 6j amplifier 00e ABI aN ACI 54 8 BF184 7 8 PA229 1 2 watt Audio Amplifier q S 85 NU E Ser rois 3 6 PA234 1 watt Audio Auiplifier DE gi Sony fi eo ETE HT BEI93 8j PA237 2 watts Audio Amplifiei ar 40 ees d ae ce 6 0 BF196 4 6 MC1709G G P operational Amplifer 3 40 aera oe RE 8 8 BFI97 4 8 TAA263 3 tage direct coupled Amplifler 2 BF ps 1n Tra Er 8 6 BFX88 5 4 TAA293 3 stage direct coupled Amplitier 207 are Ki CY17 6 BFY17 8 6 TAA320 MOST input bi polar stage 18j STA xen 4 BFY18 bf TADIOO All active components required to construct SN1304 iie ACYI9 4 9 BFYi9 5j an AM receiver uo c0 TBI tu ivi aut 16 ACY20 4 BFY50 5j 8L403A 3 watts Audio Aniplilier T 49 8 in tube fitted with telescupic viewing lood giving 2N1305 4 6 old a F pa 416 bright di
122. 41008 J1007 J1008 J1009 P Poly 2400ft J1010 7 T P Poly 3600tt C60 Cassette Library cased C90 Cassette Library cased C120 Cassette Library cased NEW PVC 22Btt PVC 900ft P Poly 1200ft PVC 1200ft 5 6 P Poly 600ft 10 6 P Poly 1800ft 22 6 P PVC 2200f 12 6 PVC 1800ft 17 6 sd Hd Hd Fd d Hd Hd Hj nd Hd Hd Fdo o gt Re Re amp RR Rr Pr CR amp ER Ot ER fa as Lo a Los Das Lao as ac Ro lle fO NO tO ND BD foi bed oi ps V Cita M ngg M a SAAHee ent red BO STP 800 8 TRACK STEREO CARTRIDGE HOME PLAYER TELETON STP 800 8 TRACK STEREO CARTRIDGE HOME PLAYER 4 complete solid state unit ready to plug in and play Hi Fi reproduction at 32 Lp s Player unit incorporates Volume tone and balance controls and push button track selector Size 141 x 101 Matched speakers size 11 x 8 x 51 each LIND AIR PRICE 49 GNS Complete with all components for building Into suitable cabinets Unit 3 Kit 11 19 6 each 91 per pair Unit 4 Kit 16 0 0 each 28gns per pair Unit 5 Kit 28 10 0 each 39gns per pair P amp P 10 each 15 pair SAVE ON AKAI AK AI 4000 Stereo Tape Recorder List Price 194 18 0 as illus OUR 99 Gns car 20 AKAI 4000D STEREO TAPE DECK Liat Price 89 19 1 Carr ao TELETON SAQ203 TRANSISTOR STER superb quality hi fi 10 watts per channel music power Inputa for Gram Magnetic and Crystal Tuner and Auxilia
123. 441AN 10 UIC76 5x7476N 10 j UIC96 5x7496N 10 BP20 7420N Dual 4 Input NAND GATE 8 6 5 6 4 8 UICXI 90 x asst d 74 3 30 BP30 7430N Single 8 Input NAND GATE 6 6 5 6 4 6 Packs cannot be split but 20 assorted pieces our mix is available as PAK UICX1 BP40 7440N Dual 4 Input BUFFER GATE 8 6 5 6 4 6 Every PAK carries our BI PAK Satisfaction or money back GUARANTEE BP4 7441AN BOD to decimal decoder and NIT AES e DUAL IN LINE LOW PROFILE SOCKETS river Bub daan MR donas siri RA 22 6 20 17 6 14 SAND BRO Leads Rocket for meets eh ual inr inaha terissod cirea BP50 7450N Dual 2 Input ANDIOBINOT GALE Order No 1 94 25 99 100up expandable 6 6 5 6 4 6 T8014 e pin type n B 18 4n JE BP53 7453N Single 8 Input ANDIOR NOT TEE A CE hl et Edere ER T ei ura n RTL FAIRCHILD U S A I C s BP60 7460 In a ble Ney Dual EToPut s exutus ule dog RTL Micrologic Circuit Qty prices each BP70 7470N Single JK Flip flop edge triggered 9 8 lim Epoxy uel To 5 temp range 15 C Doe ni ET 25 vs soe i ip E a E pL 900 er BP72 7472N Single Master Slave JK Flip flop 9 8j 7l UL 914 Dual Abby GATE 8 7 66 5 6 BP73 7473N Dual Master Slave JK Flip flop 10 9 8 6 go xt a K e ra or btt ba 10 9 8 9 A ata and circuits for in Booklet form price eac BP74 7474N Dual D Flip fiop 10 9 8 6 LAT03E Linear RF IF AMPLIFIER n 10 7 9 8 8 BP75 7475N Quad Bistable Latch uj 10 9 6 PLASTIC CASE To 5 6 lead up to 100 m ca BP76 7
124. 476N Dual Master Slave a ius iEn preset and clear 5 A 11 10 9 6 DTL DIGITAL l C s a Ps DTL dual in line package Price DPSS pr eu HOLD ACT cdi apie Eu Type MC844P expandable dual 4 input NAND Power Sale 10 each BP90 7490N BCD Decade Counter 22 6 20 17 8 Type Mona Clocked Lp on NOR i oe Tt Type 862 Triple 3 inpu i OR ate A eac BP92 7492N Divide by 12 4 Bit binary counter 22 8 20 17 8 FULL DATA SUPPLIED WITH UNITS BP93 7493N Divide by 16 4 Bit binary counter 22 6 20 17 8 ATI T r nt BP94 7494N Dual Entry 4 Bit Shift Register 22 8 20 17 6 Please send all orders direct to our warehouse and despatch depar RS BP95 7495N 4Bit Up Down Shift Register 22 8 20 17 6 BI PAK SEMICONDUCTOR BP96 7496N 65 Bit shift register 24 21 18 6 P O BOX 6 WARE HERTS Postage and packing add 1 Overseas add extra for Airmail Minimum order Datais available for the above Series of Integrated circuits in booklet form price 2 6 10 Cash with order please 335 ORS NO 10 Small portable crystai controlled BELCO AF 5A SOLID STATE SINE SQUARE UNR 30 4 BAND COMMUNICATION RECEIVER WAVE C R OSCILLATOR Covering 550 Kca 30 Mc s Incorporates BFO Buil wavemeter Size Mine 18 200 000 Hz Square 18 50 000 Hz in speaker and phone jack Metal cabinet Operation EUN cU xe x 4in Output may In dB 10 K ohms 220 240V A C Supplied brand new guaranteed with MEETS TE HR M b Frequency range Sos Operation
125. 4l 10 EF80 5 6 KT88 34 PEN4s 7 U25 15 6 VR150 30 6 5Z4G 6 6 68N7GT 5 0 I El 20 30PI9 15 AU9 80 EB91 8 EF91 3 6 KT Wal 12 6 PEN46 4 U26 15 6 VT90 15 6 30L2 12 6 68Q7 7 6 1235GT 2 6 30PLI 16 AUS 9 EBC33 8 6 EF9 92 8 KTZ4l 6 PL36 10 9 U73 4j6 VT31 80 6A7 16 6U4GT 12 12J7GT 6 6 30PLI3 18 6 AZ1 8 EBC4 8 9 EF98 15 ML4 17 6 PLSl 9 6 UI9 18 09 VUlll 8 9 6A8G 14 6U5G 7 9 12K7GT 7 30PLI4 15 AZ31 10j EBC90 4 9 EFI83 amp 6 ML amp 6 7 6 PL89 8 68 U95 16 3 vU120 12 6 6ACT7 15 6V6M 12 I2K8GT 8 30A5 12 6 CBL31 16 EBF80 7 6 EFI84 7 MSP4 10 PL83 7 6 U30 12 6 VUBOS 35 6AK5 14 6V6G 4 8 12Q7GT 6 35L6 9 CCH35 15 EBF83 9 EL32 3 6 MUl4 7 6 PL84 7 U403 6 8 W8SIM 13 6 6AM5 2 9 evoGT 6 6 12847 8 35W4 4 6 CL33 20 EBF89 6 6 EL33 12 6 MX40 12 6 PLo00 14 6 0404 7 6 XHl 5 6AM6 3 6 6X4 4 6 128G7 6 35Z3 10 CV450 25 EBLI 14 EL34 10 6 N78 19 PLo04 16 USO 23 8 XPl 0 85 6AQ5 3 6X5G 4 6 19SH7 3 35Z4GT 8 6 CY30 12 6 BBL21 12 EL38 22 6 N108 25 PL6O8 29 UABC80 6 6 Y63 7 6 6AS7G 9 i6X5GT 6 128 7 3 9 35Z5 6 CY31 8 6 EBL31 927 6 EL4di 1ll NGTl 3 6 PL 09 29 UAF42 10 8 Tubes 6AT6 4 7B6 11 8 D8SK7 4 9 37 6 6 DACS 7 EC90 5 EL42 11 8 042 6 PL802 16 8 UBC4l 9 8 3EGI 65 6AU6 5 6 7B7 7 6 SR 5 42 8 DAFO1 4 6 ECCS1 6 EL84 4 9 OC3 5 PX4 94 UBCRl 9 8 3FP7 29 6B4G 3 6 7 Co 29 6 4H7 9 6 5085 6 6 DAF95 7
126. 6 ECF83 15 EL95 7j PCE80015 PY33 19 6 UCH21 11 xs 76 day 280 akan 15 I2 NT 6 30F 17 ROGA 14 DYB7 T7 ECF86 12 8 ELa60 23 PCF80 8 6 PY8n 6 6 CCII42 13 BUT Za RUE ia ic J9AY 13 30FLI 15 5642 12 DY80 10 ECF80480 ELS03 17 PCF82 6 9 PYAL Bi UCH43 12 Exod dA Seip tee Ms ART 7 18 6 6 90 E55L 55 ECH42 18 ELR 1 1lj PCE84 9 PY 6 UCHR 6 6 ds Souto SO CIA et eres se iy Pt le ESRCC 8 ECHSI 5 9 ELLSO 16 PCFS6 11 PYa3 58 UC S Mj SB2R 42 6 GRXG 5 SLIS 6j I2BAn 6 6 30FLI310 6148 6 6 E1301 100 ECHAS 8 6 EM71 12 6 PCERT 18 PYsx 8 GLR 7 Sex esser vk liso E SGA felon SUELE xs RM one EIB0F 19 ECH84 9 EM80 8 PCF80015 PY500 20 UCLS3 19 DA Ea DR RV ap hate i Bhs 8 6 ma T 6939 42 E280F 49 ECL80 9 EM84 7 8 PCF80110 PYROO 10 CF9 11 A IE oe 6 12BY7 10 30L17 17 7199 15 EBlOF 57 8 ECLSI 8 6 EM87 11 POFSO210 PYSOL 10A CFII 10 Aviv ROO ae tar Me EFI MB 1960 36 EABC8O 6 6 ECL82 6 6 ENS 6 8 PCF80515 PZ30 7 VFS 10h uae be hee See ef UR Sopa de 7586 5 EAF42 10 ECL83 12 6 EY L 8 PCF80818 QQVO9 5 UF49 18 Shige ge eGbona ago go abre eee auri aes 900 8 6 EBC33 9 ECLS4 11 EYBO PCF808 15 6 42 UF43 11 Er 5 Et by SIA 1b 12A CT S 30P LI 15 6 9005 10 4 EBC4 10 8 ECL8s 10 6 Eys
127. 61 BFX13 BFX29 BFX30 BFX35 BFX43 BFX44 BFX84 BFX85 AF126 5 6 AF127 11 AF139 15 AF181 3 6 AF186 4 6 AF239 4 6 ASY26 4 ASY27 4 6 ASY28 4j ASY29 3 6 ASZ20 3 6 ASZ21 4j BA102 BAX18 BAX16 BAY3I BFX86 BAY38 BFX87 BC107 BFX88 BC108 BFY43 BC109 BFY50 NKT8011219 6 BC113 BFY51 NK1T8011322 6 BC116 BFY52 OAS 6 BC118 BFY76 OA BC125 BFY90 O ATO BC126 BSX19 OAT3 BC147 BSX20 OAT9 BCi48 BSX21 OASI BC149 BSX26 OAR5 BC167 BSX27 0490 BC168B BSX28 OA91 BC168C BSY29 18 OA95 BC169B BSY26 OA200 BC169C BSY27 0 4202 BC182L BSY28 0C26 BC212L BSY99 OC98 BCY30 BSY38 0C29 BCY31 BSY39 OC35 BCY32 BSY40 OC36 BCY33 BSY51 OC44 BCY34 BSY52 0C45 BCY38 BSY53 OCT71 BCY39 BSY54 OC72 BCY40 BSY95A OC75 BCY42 BY100 ocsi BCY43 BYX10 OC83 BCY54 BYZ20 OC81 D BCY70 BYZii OC84 BCY71 BYZIS OC139 BCY72 BYZ13 OC140 BDY20 MJ480 OC200 BD116 MJ48 OC201 BDI21 MJ490 0C202 BD123 MJ491 OCP71 BDi24 MJES20 ORP12 BD131 MJE521 ORP61 7 6 PLESSEY INTEGRATED CIRCUITS SL408A 45 6 BLA03A 42 6 Data Sheets 2j MULLARD LINEAR l1 C s TAA 241 T AA 42 TA A943 TAA 68 TA A203 TAASOG TAASIO TA A320 TAASDO TAAd35 l AA521 TAAD92 TAASI1 TAB101 T AD100 TADIIO Data Sheets 1 Free with I C s Also most Mullard Logies in stock Heatsinks TO 18 TO 5 TO 1 1 FINNED FOR ONE TO 8 6 6 FINNED FOR TWO TO 3 9 6 THERM STORS R53 STO 25 6 K151 1K 2 6
128. 6V6G 3 8 B729 12 6 EF37A 6 6 PCC89 10 6 6V6GT 6 6 CCH35 18 60 EF39 4 9 PCC189 9 9 6X4 4 3 CL33 18 6 EF41 11 9 PCC805 18 X5GT 5 9 CY31 6 9 EF80 4 6 PCF80 6 6 10F1 14 DAC32 7 8 EF85 6 8 PCF82 6 6 10F18 7 DAF91 4 38 EF86 6 3 PCF86 10 10P13 12 DAF96 7 3 EF89 5 3 PCF800 13 6 12AT7 3 9 DF33 7 9 EF91 2 98 PCF801 6 8 I2AUS 4 9 DF931 2 9 EF183 5 9 PCF802 9 19AU7 4 9 DF96 7 3 EF184 6 6 PCF80513 6 12AX7 4 9 DH77 4 EH90 6 3 PCF806 12 9 129K8GT 7 3 DK32 7 6 EL33 9 9 PCF80814 6 19BG6G17 8 DK91 5 9 EL34 8 PCL82 7 3 20F2 18 6 DK92 8 6 EL4 11 PCL83 18 T el 01 550 7441 Postage on 1 valve 9d extra On 2 valves or more postage 6d per valve extra Any Parcel Insured against Damage in Transit Gd extra 406 12 8 6 6 4 6 1st LF Transformer ou T41 2bE 2nd I F Transformer T41 3T 3rd I F Transformer T41 3T B F O Coil Details of these and our other components are given in an illustrated folder which will be supplied on Da rr DC KC c C f C e pe ip o A r e a a a ep P50 1AC For OC45 P50 1AC For AF117 5 4 P50 2CC For OC45 P51 1 P50 2CC For OC45 P51 2 P50 3CC For OC45 P50 3V For AF117 UU RASW ii A216 CERTA rm 9 6 OPT1 10 6 POLL EE ee 9 6 7 6 7 6 10 6 10 6 For AF117 For AF117 BAKER 12in MAJOR 9 Send 4d Stamp for further Details MAKES 5 DIFFERENT TRANSISTOR RADIOS Total Building Price 39 6 Ama
129. 8 plus 1 post Suitable box for wall mounting 5 P amp P 1 Type B 15 amp This la a 17 n long rod type made by the famous Bunvlo Co Spindle adjusts X this from 60 550 F Internal sorew altera the setting so this could be adiustable aver 40 to 1000 F Buitable for oontrolling fur nace oven klin Im mersion heater or to make flame stat or fire alarm 8 8 plus 2 8 post and Insurance Type D We call this the Ice stat as It cuts in and out at around freezing point 2 3 amps Has many uses one of which would be to keep the loft pipes from freezing if a length of our blanket wire 16 yd 10 1s wound round the pipes 7 6 P amp P 1 Type E This is standard retrigerator thermo stat Bpindie adjustinenta cover normal retrigera tor temperature 9 8 plus 1 post Type F Glass encased for controlling the temp of liquid particularly those in glass tanks vate or sinks thermostat is held half submerged by rubber sucker or wire clip ldeal for fish tanka developers and chemical baths of all types Adjustable over range 50 to 150 F Price 18 plus 2 post and insurance THERMOSTAT Continuously variable 30 90 C Has sensor bulb connected by 33in of flexible tubiug On operation 15 amp 2650 volt i switch is opened and in addition a plunger moves through approx in This could be used to open valve on ventilator etc 29 6 plus 4 6 p amp ins 230 VOLT SOLENOID tin str
130. 9 x 6 Completely built and tested on steel Chassis PRICE 35 0 0 inc P amp P For full details of these and all Discosound Products write direct to DISCOSOUND 122 BALLS POND ROAD LONDON N 1 Tel 01 254 5779 Full money back guarantee if returned within 10 days All Discosound Products are guaranteed for 12 months Demonstrations given at any time 339 R S C SENSATIONAL HIGH FIDELITY STEREO PACKAGE OFFERS Super 30 Amplifier 15 15 watt in veneered housing Matching as recommended for optimum Super 30 amplifier 15 I5 watt in Goldring Transcription Turntable on Plinth Performance Send for coloured brochure veneered housing Shure or Goldring Magnetic Pick up Cartridge showing other Money saving offers Garrard SP25 Mk II Turntable on Plinth X Pair of Stanway Il Loudspeaker Units Package prices apply pro Goldring CS90 Ceramic P U Cartridge Speciai total price Four fully wired 86 Gns viding all individual units with diamond stylus units ready to plug in Carr 30 Iw accettate are purchased frum auy Pair St TAIS Amplifier 6 5 6 5 watt in veneered housing Garrard branch within 3 months ik MASS DORA Res Dpits k 8000 4 ap Autochanger unit on plinth Sonotone STA P U cart See leatlet Four fully wired units realy to 76 Gns Carr e plug in Special total price 30 O TA12 Amplifier 6 5 6 5 watt in veneered housing Garrard 8P25 Mk II 4 sp player unit on plinth
131. CH6 11 6K25 14 ECL83 10 6 PABC80 7 6 PYS01 9 6 0801 20 VR105 30 6 5B 255M 35 6AS6 6 6CL6 B 9IGL6GT 9 P C RADIO LTD 170 GOLDHAWK RD W 12 01 743 4946 Los f SA sus at 1 5 0 E LL Lc fis Bolve your communica X tlon problems with this 4 Bintion Transistor Interoom system 1 master and 8 Bubs in de luxe plastic cabinets for desk or wall mounting Call talk listen from Master to Subs and Subs to Master Ideally suitable for Business Sur gery Schools Hospital Office and Home Operates on one 9V battery On off switch Volume control Complete with 3 connecting wires each 68ft and other accessories P amp P 7 8 MAINS INTERCOM No batteries no wires Just plug in the mains for instant two way loud and clear communication On off switch and volume control Price 11 19 6 P amp P 8 6 extra BA flame as 4 Station Intercom for two way instant communication Ideal as Baby Alarm and Door Phone Complete with 66ft connecting wire Battery 2 6 P amp P 4 6 Why not boost business ef olenoy with this incredible De luxe Telephone Ampli fier Take down long telephone messages or converse without holding the handset A useful office aid On oft switch Volume Control Battery 2 6 extra P amp P 8 6 Full price refunded if not satisfled in 7 days WEST LONDON DIRECT SUPPLIES P w4 169 KENSINGTON HIGH STREET LONDON W
132. CS LIMITED 22 NEWMARKET ROAD CAMBRIDGE Telephone 0223 52731 395 Project 60 laboratory standard high fidelity modules Sinclair Project 60 comprises a range of modules which connect together simply to form a compact stereo amplifier with reaily excellent performance So good in fact that only 2 or 3 amplifiers in the world can compare in overall per formance Now with the addition of three new modules to the range the constructor has choice of assemblies with either 20 or 40 watts output per channel with or without filter facilities The modules are 1 The Z 30 and Z 50 high gain power amplifiers each of which is an immensely flexible unit in its own right 2 The Stereo 60 pre amplifier and control unit 3 The Active Filter unit with both high and low audio frequency cut ofis 4 The PZ 5 and PZ 6 power supplies A complete system could comprise for example two Z 30 s one Stereo 60 and a PZ 5 The PZ 6 is stabilised and should be used where the highest possible continuous sine wave rating is required An A F U may be added as required In a normal domestic application there will be no significant difference between using a PZ 5 or PZ 6 unless loudspeakers of very low efficiency are being used in which case the PZ 6 will be required For assemblies using two Z 50 s there is the SINCLAIR RADIONICS LIMITED 396 22 NEWMARKET ROAD CAMBRIDGE new PZ 8 stabilised supply unit to ensure maximum per formance from these
133. D RSC AIO 30 WATT ULTRA LINEAR HI FI Highly sensitive Pusb Pull AMPLIFIER high output with Pre amp Tone Control Stages Performauce fignres of factory built units Hum level 70dB Frequency response 3dB 30 20 000c s Sectionally wound utput transformer Al high grade components valves EF86 EF86 ECC83 807 807 GZ34 Separate Bass and Treble Controls Sensitivity 36mv Suitable for high impedance Microphones imme Crystal or Ceramic P U s Designed for Clubs Schools Theatres Dance Halis or Outdoor Functions etc l or use with Electronic Organ Guitar String Bass etc Gram Radio or Tape Reserve L T and H T for Radio Tuner Two inputs with associated volume controla so that two separate inputs such as Gram and Mike can be mixed 200 250v 90c 8 A C mains For 3 and 10 ohm speakers Complete kit of parts with point to point wiring diagrams and instruc 15 Gns Carr tions 12 6 Twin handled perforated cover 85 Supplied factory built with EL34 ontput valves 19 montbs guarantee for 18 gns TERMS Deposit 3 9 0 and 9 monthly payments of 2 Total 21 9 0 Send 8 4 E for Jeaflet RSC All HIGH FIDELITY 12 14 WATT AMPLIFIER PUSH PULL ULTRA LINEAR OUTPUT BUILT IN TONE CONTROL PRE AMP Two input sockets with mixing facilities High sensitivity 5 valves Independent Bass and treble controls Frequency response 3dB 30 20 000 c s Hum level 60dB Sensitivity 40 milli v
134. End pieces C 2 required 3 ply wood Base cover hardboard End piece Rear top member 2 2 Lower cross members N IRA T AN Top cross members LEAD O SAE GA I A namataan ee om US ee l a a AEE EEE SD O SS Re ST A RUE RR a Ut UOTA E ECTE Cas UA UR EDU 7 RC i es Fig 7 Construction of the framework for the case Before fitting the pedals the case must be com pleted by first making and assembling the two end pieces Fig 7C and then by building up the frame work Figs 7 and Fig 8 Note the shape of the upper pedal stop rail Fig 7A Wood of this shape can be obtained from most D LY decorating materials shops The alternative would be to use a rail 14 x iin and drop the front panel accordingly The frame members Fig 8 can be glued in place with Evostik Leave the lower rear member Fig 8 until the pedals have been secured in place Pieces of hardboard cut to appropriate size can be glued to the frame members to form a box for the PP9 battery at the right hand end of the frame looking from the rear as shown in the photograph Contact Rail and Keying Contacts The contact support rail is U shaped aluminium channelling and fits underneath the pedal frame in the slots at the sides Figs 2A 3 7A and 9 Dimensions and drilling details for the rail are given Fig 10 Note that the fixing holes for the contact assemblies must be 3 32in in diameter to ta
135. F ceramic TOLF 12VW elec Semiconductors Trt 2 BC109 Miscellaneous s Switch 2 pole 4 way wafer Veroboard 33 x 1 in 0 1in matrix Panel 5 x 23in 18 s w g aluminium Output socket Knobs Case Testing The prototype was tested by connecting the output to an oscilloscope which showed a satisfactory wave form when the Tr2 circuit was functioning The other oscillator was switched in and adjusted for amplitude by means of VR This waveform was also found satisfactory When both oscillators were operating simultaneously it was found necessary to make a small re adjustment to VR1 which also had an effect on the operating frequency The outputs were checked for frequency and found to be 950 and 1900Hz respectively tt 5 q zi i a 18swg aluminium panel Circuit board 12V Fig 4 Mounting of circuit board function switch attenuator and outpul socket on panel Conclusion Although intended mainly for use when adjusting s s b transmitters other uses for the unit are possible and some will doubtless spring to mind If preferred only one half of the unit a single sine wave oscillator may be constructed Recording enthusiasts may find the device useful as a Tape Tailer and if its signal is introduced as the recording nears the end of the tape on playback the warning note will save much re threading on to an empty spool E ryg a Em CATETE E
136. F ceramic VC1 100pF variable Semi conductors Tr1 AF1170r AF 115 Tr2 AF 117 or AF 115 inductors L1 Miniature transistor type Denco Range 4 blue RFC 1 Miniature ferrite cored choke 1 5mH Miscellaneous Miniature switch 2P 2W slide type K 6 x Gin aluminium sheet 6V battery Coaxial socket Tag strips etc meter reading noted If S1 is next moved to its In position the amplifying effect of the preselector will be soon noted as VCI is tuned to peak the trans mission The preselector can then be similarly tested on the 21 and 28MHz bands and thereafter finalized as required to suit the particular location Should it be found that the 21MHz band peaks when the vanes of VCI are almost fully disengaged it will not be possible to achieve signal peaking on 28MHz in such cases three turns may be re moved from the tuned winding of coil L1 To do this carefully snip the winding clear where it terminates at pin No 6 unwind the necessary number of turns slowly snip off the unwanted wire and re make tbe connec tion to the vacated pin Advantages the simple preselector described has over a valved version are a physically small size plus the fact that it is com pletely independent of any mains connection and is thus safe On the debit side noise generated by the transistorised preselec tor tends to be higher than that developed by a good valved specimen Since to some extent noise to signal ratio changes wi
137. FX34 NKT42 6 7 NKT225 3 6 NKT734 4 11 OC205 9 2 26381 5j 2N3055 15 OAS 3 8 ACY36 39 BC137 8 6 BFX44 8 NKT43 6 NKT226 11 7 NKT736 6 2 OC206 10 6 2N385A 2N3235 23 6 OA10 6 ACY39 12 77 BC138 12 j BFX84 5 2 NKT72 3 9 NKT227 9 6 NKT773 37 OC207 7 6 2N388A 15 2N339fA 6 OA47 1 8 ACY40 3 BC140 13 3 BFX85 6 9 NKT73 37 NKT228 6 6 NKT774 6 2 OCP71 19 6 2N404 4 6 2N3392 5 OATO 1 8 ACY41 3 BC147 2 9 BFXB6 4 11 NKT101 6 NKT229 311 NKTo0013 6 8 ORP12 9 6 2N696 3 7 2N3393 5 OAT3 1 8 ACYA4 8 BC148 3 3 BFX87 5 11 NKT102 6 NKT231 6 NKT10419 3 10 ORP60 8 2N697 3 10 2N3525 21 9 OATS 1 8 AD140 11 BC149 3 BFX88 5 3 NKT103 6 NKT232 6 NKT10519 4 5 ORP61 B 2N698 6 2N3702 2 6 0481 1 8 AD149 11 6 BC154 12 7 BFY18 15 NKT104 6 NKT237 5 9 NKT10339 4 7 ORP63 9 2N706 2 4 2N3703 2 5 OAS5 1 8 AD161 6 BC167 3 6 BFY50 4 6 NKT105 6 7 NKT238 4 NKT10439 5 5 P346A 3 9 2N706A 2 6 2N3704 32 OASO 18 AD162 6 BC168 39 BFYS51 3 9 NKT106 6 NKT239 4 NKT12329 8 5 RAS310AF 6 2N708 3 3 2N3705 2 8 OA91 1 8 ADT140 12 6 BC169 39 BFY52 4 6 NKT107 6 NKT240 310 NKT12429 10 6 RASSOSAF 15 2N709 8 6 2N3706 2 3 OAO95 1 8 ADZ11 32 BC171 f BFY53 3 2 NKT108 6 NKT241 39 NKT13329 3 11 RS220F 4j 2N711 7 6 2N3707 2 10 O A200 2 AF102 12 6 BC182L 2 3 BFY90 24 6 NKT109 6 NKT242 2 14 NKT13429 3 141 SIM 19 2N711A 76 2N3708 110 OA202 2j AF106 7 6 BC183L 1 10 BFYW57 6 NKT121 10 6 NKT243 12 NKT16229 3 5 S4M 33 6 2N743 4 6 2N3709 2 OA 11 8
138. Fellow of the British Computer Society and avoids the use of jargon The basic kit costs only 7 Gns and can be supplied in assembled form ready for use for an extra 27s 6d Further details from Limrose Electronics Lymm Cheshire 347 E FOR TREBLE OR BASS GUITAR ORGAN AND MICROPHONE WITH NEW TONE TREMULANT SYSTEM BUILT IN MIXING VISUAL TREMULANT INDICATOR MAX 50 WATTS R M S POWER COMPLETELY SELF CONTAINED OPTIONAL FOOT CONTROLLED TREMULANT AND WAH WAH with facilities similar to those of the PW 25 50 and which will be fully dealt with in this and following articles do not come cheaply com mercially made equivalent would cost in the region of 150 or more All the components including the power module its power supply the cabinet materials and the two special Goodmans power loudspeakers specified can be obtained for approxi mately half this price The finished 50 watt amplifier is neither small nor light in weight because of the twin heavy duty loudspeakers and the very necessary rugged cabinet construction which is essential for power reproduc tion of guitar bass at the full 50 watts r m s output The cabinet is constructed from iin thick Weyroc compressed chipboard There is however an alternative arrangement with regard to the loudspeakers and power output For those who require the amplifier for treble guitar only with less power a single type 12P 8 ohm Goodmans power speaker ca
139. Fig 1 The circuit of the field strength meter Components to the right of the dotted line are only needed where the extra sensitivity version is required and here the meter is across the bridge circuit the reading on the meter will bear a direct relation ship to the strength of the signal received at the tuned circuit i The on off switch is incorporated with VR1 but care should be taken to ensure that it is wired as shown The battery used is a 1 5V pencell CONSTRUCTION The only component to be constructed is L1 the coil This is wound on iin dowelling or anything of similar diameter which may be later removed Starting at one end of the former using l s w g enamelled wire leaving about 24in spare wind on 8 turns close wound A small portion of the wire FIELD STRENGTH E METER RICHARD COLLINS should then be bared of enamel so that a tapping can be soldered on later Another 4 turns are now wound making a 12 turn coil tapped at 8 turns The coil can then be slipped off the former and stretched to a length of 11in Although the wiring is simple Fig 2 it should be carried out with care Every wire should be as straight as possible Stiff wire is best as it is less likely to vibrate and cause slight variations in meter readings The unit may be housed in a small box measuring about 21 x 3 x 6in and the 25pF capacitor should preferably be of the ceramic base type with silver plated plates Meter b c T
140. Filter slope both sections 12dB per octave Distortion at 1kHz 85V supply 0 02 at rated output SINCLAIR POWER SUPPLY UNITS PZ 5 30 volts unstabilised 4 19 6 PZ 6 35 volts stabilised 1 19 6 PZ 8 45 volts stabilised less mains transformer 5 19 6 PZ 8 Mains transformer 5 19 6 GUARANTEE O input sensitivities Radio up to 3mV Mag p u 3mV correct to R I A A curve 1dB 20 to 25 000Hz Ceramlc p u up to 3mV Aux up to 3mV O Output 250mV S Sicbal te nolse ratio better than 70 dB O Channel matching wlth n 1dB O Tone controls TREBLE 15 to 15dB at 10 kHz BASS 15 to 15dB at100Hz O Power consumption 5mA O Front panel brushed aluminium wlth black knobs and controis Size8z x1 x 4 ins Bullt tested 9 1 o 6 and guaranteed E a X ce mM A as HIGH PASS LOW PASS Built tested and guaranteed 5 1 9 6 The illustration here shows quite clearly how easily Project 60 can be contalned in one of today s sllm modern plinths Very little space Is required to house these Sin clair units and within the space of the motor plinth you can Install a stereo amplifler of the very highest quality If for example you have already put together an assembly as Illus trated here adding the Active Filter Unlt would be very easy SN BUILDING A PROJECT p RN 60 ASSEMBLY The ne w Project 60 Manual 50 pages 2 6d If w
141. GE The base bias voltage on transistors is usually 376 No 17 MULTIMETER EXTRAS ve Rx see text Meter on lowest current range ve ve Fig 2 Adding a 1V range is a simple matter but refer to the text for the value of Rx between 0 3V and 0 8V but only a few meters have a 1V range However this can be added simply by the addition of a resistor With the meter on its lowest current range and a resistor equal to the meters sensitivity a 1V range is added Thus a 1 0000 V meter would need a 1kQ and a 20 0000 V meter a 20k resistor Unfortunately the internal resistance of the meter has to be subtracted from this The simplest way to find the correct value is to fix a 1000 pot across a 1 5V battery and adjust so that a IV reading is obtained on your testmeter This should be done with care as the accuracy of the scale will depend upon it Then change over to the lowest current range and select a resistor that will give full scale deflection from the 1V supply This will probably mean using two or even three resistors in series once the exact value has been found the resistors can be soldered together A C CURRENT RANGE Only the most expensive multimeters include an a c current range and although this is rarely needed it is sometimes necessary to measure mains current If a 10 resistor is inserted in the line a 1A current will drop 1V and a 100 resistor will drop 10V and O course we can measure a c volts W
142. I PU2 Tape Radio The HSL 700 is strongly constructed on rigid steel chassis bronze hammer enamel finish size 9 x 5 x 4 in high Sensitivity PU1 50m v 56K input impedance PU2 110m v 1 meg input impedance Tape 110m v 1 meg input impedance Radio 110mj v 1 meg input impedance Output power measured at 1Kc 6 2 watts RMS into 3 ohms 5 8 watts RMS into 15 ohm Overall frequency response 30 c s 18 Ke s Continuously variable tone controls Bass 8db to l2db at 100c s Treble 10db to 10db at 10Ke s The HSL 700 has been designed for true high fidelity reproduction from Radio Tuner Gramophone deck and Tape Recorder preamp Supplied ready built and tested complete with knobs attractive anodised aluminium front escutcheon panel long spindles can be cut to suit your housing require ments full circuit diagram and operating instructions Our Special Price 7 19 6 pap LOUDSPEAKER BARGAINS 3 4 ohm 10 P amp P 1 6 Sin 3 ohm 16 P amp P 3 7 x 4in 3 ohm 21 P amp P 4 10 x 6in 3 ohm 27 6 P amp P 6 E M I 8 x Sin 3 ohm with high flux magnet 26 P amp P 4 E M I 134 x in 3 ohm with high flux ceramic magnet 48 15 ohm 45 P amp P 6 E M I 13 x 8in 3 or 15 ohm with two inbuilt tweeters and crossover network 4 gns P amp P 6 BRAND NEW 12in low H D Speakers 3 or 15 ohms Current production by well known British maker Now with Hiflux ceramic ferrobar m
143. IND IN THE WORLD Published approximately on the 7th ot each month by IPC Magazines Limited Fleetway House Farringdon Street London E C 4 Tel 01 236 8 inted i i Dunstable Beds Sole Agents for Australia and New Zealanii Gordon ani Gotch A sia Ltd South Africa Central News ieee ae eee i ae vnd RD E ee Africa Stationery and Office Supplies Ltd Subscription rate including postage For one year to any part of the world 2 5s Od 4 PRACTICAL WIRELESS is sold subject to the following conditions namely that it shall not without the written consent of the Publishers first given be lent resold hired out or otherwise disposed of by way of Trade at more than the recommended selling price shown on the cover and that it shall not be lent resold or hired out or otherwise disposed oi in a muti lated condition or any unauthorised cover by way of Trade or affixel to as part of any publication or advertising literary or pictorial matter whatsoever THE B LE T E Tr e o U HENRY S RADIO LTD VAL ORDER AND INDUSTRIAL SALES DEPT 303 EDGWARE ROAD LONDON W 2 01 723 1008 9 O ELE RONIC COMPONENTS AND EQUIPMENT 356 EDGWARE ROAD LONDON W 2 T L 01 402 4736 Ld COMPLETE STEREO SYSTEM FOR 39 10 0 HENELEC 5 5 STEREO AMPLIFIER Inputs for ceramic cartridge Aux Tuner Output for 8 to I5 ohms speakers Silver with black and wood finish British made Size 123 x 34 x 61 Fitted headphone
144. LFDT4 9 6 I F P50 2CC 470 ko s 5 7 Printed Circuit PCAl 9 6 amp rd I F P60 8CC 6 J B Tuning Gang 10 6 BRE or P51 2 6 7 Weyrad Booklet 2j PEII A nA 6 2 VORTI SA es 10 6 Ferrite Rod 8 x Fin 4 6 x iin 5 VOLUME CONTROLS 800im Coax 9a sa Long spindles Midget Size BRITISH AERIALITE 5 sm ohms to 2 Tp Log or AERAXIAL AIR BPACED L 8 3 5j 40 yd 28 80 yd 40j STEREO L 8 11 D P 15 FRINGE LOW LOSS 2 Edge 6K 8 P Transistor 5 Ideal 625 lines yd WIRE WOUND 3 WATT POTS WIRE WOUND3 WATT Small type with small sj STANDARD SIZE POTS Values 10 O to 30 K LONG SPINDLE 8 Carbon 30 K to 2 meg 10 OHMS to 100 K VEROBOARD 0 15 MATRIX 24 x 5in 8 8 24 x 31in 3 2 31 x 81in 3 8 32 x Bin 5 2 EDGE CONNECTORS 16 way 5 24 way 7 8 PINS 86 per packet 8 4 FACE CUTTERS 7 6 B R B P Board 0 15 MATRIX 2tin wide 6d per lin 3 in wide 9d per 1 in Sin side 1 per lin up to 17in 8 R B P undrilled yin Board 10 x Sin 3 ee RA ee ee 00 7 BLANK ALUMINIUM CHASSIS 18 s w g 2tin sides 7 x 4in 6 11 x 3in 7 6 11 x 7in 9 6 13 x 8in 10 6 15 x 14in 15 9 x 7x 2in 8 6 14 x 11 x 2in 14 6 ALUMINIUM PANELS 18 s w g 12 x 12in 6 8 14 x Bin 5 8 12 x Sin 4 0 10 x in 3 6 8 x Gin 2 6 6 x 4in 1 0 l inch DIAMETER WAVE CHANGE SWITCHES 2 p 2 way or 2 p 6 way or 8 p 4 way 4 6 each p 12 way or 4 p 2 way or 4
145. M 160 8 6 129 19 6 PIONEER SX990 AM FM 194 14 8 155 0 0 TELETON F 2000 ves 51 0 O 37 19 6 TELETON7ATI 133 0 0 85 0 0 TELETON R4200 51 15 0 39 19 6 TELETON CR 10T 39 0 0 2919 TELETON TFS50 74 00 5919 6 Ail above Tuner Amplifiers are complete with MPX decoder CARTRIDGE ALE MAKES STOCKED AT DISCOUNT PRICES PICKUP ARMS GOLDRING Lenco L75 GOLDRING Lenco L69 SME 3009 with S2 shell SME 3012 with S2 shell 12 6 6 1010 0 amp 59 70 6 31 6 3 25 19 6 33 7 3 28 19 6 COMET Hi Fi DISCOUNT WAREHOUSES w All items offered are brand new latest models in manufac turers sealed cartons Fully guaranteed with after sales service Complete Free price list of over 800 items on request All in stock items value over 50 delivered by SECURICOR WITHIN 72 HOURS Add 12 only for Securicor delivery ALL GOODS FULLY INSURED TURNTABLES ARENA SP25 with base cover 22 1 B S R MCDONALD MP60 B R S McDONALD 610 AGAINST LOSS OR DAMAGE WHILST IN TRANSIT Pee te Welcome Open Daily to the public from 9 a m Closed Tuesday 1 p m Mon amp Sat 5 30 p m Open until 8 p m Wednesday Thursday amp Friday O 17 19 6 15 0 0 1019 6 1819 6 1319 amp GARRARD SP25 fully wired with Goldring G800 magnetic cartridge komplete with base Ty and cover GARRARD SP 25 Mkll 15 1 GARRARD AP 75 23 16 GARRARD SL 55
146. M LASKY S in chassis form for you to mount in any housing that you choose All settings are achieved by two dual concentric controls at the front including ON OFF AUTO and AUTO ALARM sleep switch 10 minute division click set alarm up to 12 hour delay time adjustment Ultra simple mechanism and high quality manufacture guarantee reliable operation and long life The sleep switch will automatically turn off any appliance radio TV light etc at any pre set time up to 60 min and in conjunction with the AUTO setting will switch on the appliance again next morning The clock measures 43 W x 11H x 33D overall from front of drum to back of switch SPEC 210 240V AC 50Hz operation switch rating 250V 3A Complete with instruc tions HUNDREDS OF APPLICATIONS COMPLETE WITH KNOBS LASKY S PRICE 6 19 6 dio Development AD 309K PRECISION PICK UP ARM COMPLETE WITH AD 76K 1 Th AUDIO DE MAGNETIC VELOPMENT CARTRIDGE precision counter balanced pick up arm ready fitted with the outstanding AD 76K magnetic cartridge is constructed of brass throughout heavily chromeplated uses needle and miniature balirace bearings both coarse and flne balance adjustment is provided The fixed head has standard tin mounting centres and is finished in black enamel with chrome lifting spur Completely wired with all fixing nuts and washers Arm rest also supplied Tech details Ovetall length 285m
147. MIC709 and ZLD709C 10 6 9 8 This is a high performance operational amplifier with high impedance differential inputs and low impedance output BI PAK Semiconductors now offer you the largest and most TTL INTEGRATED CIRCUITS popular range of I C s available at these EXCLUSIVE LOW P s Manufacturers Fall outs out of spec devices including functional units and part PRICES E Digital 44N Series fully coded brand new functional but classed as out of spec from the manufacturers very ridged specificationa Dual in line plastic 14 and 16 pin packages 1 Ideal P learning about I C s and experimental work on testing some will be found gt perfect v PAK No PAK No PAK No BREAK Price and aly prices UICO0 5x7400N 10 UIC42 5x7442N 10j UIC80 5x7480N 10 Order No SIM TYPE Description 1 24 25 99 100 up vroes x 7401N dor uic 5x TABON EU prcao x Cada y a E 02 5X7402N 10 UIC51 5x7451N 10 UIC83 5x 10 BPO0 7400N Quad 2 Input NAND GATE 60 Be 4 6 UICO3 5x7408N 10 UIC80 5x7460N 10 UIC86 5 x 7486N 10 BPOL 7401N Quad 2 Input PAN Gata UIC04 5 x 7404N 10 UIC70 5x7470N 10 UIC90 5 x 7490N 10 Ty aus wo a Sous in ma ataa Nr MERCI qe 5x741 10 3 65x7473N 10 5X 10 BP04 7404N HEX INVERTER 8 6 5 8 4 6 UIC20 5x7420N ce ViCi4 5 X7474N is UICo4 5 X T494N A 39i i 0 5x7440N 10 3 5x7475N 10j C95 5x7 10 mua ci HUNC T oa EATE VORNE s UIC41 5x7
148. MIXER AMPLIFIER One of the finest units available on the market today regardless of price The front end of the unit consists of a four channel mixer with separate inputs and volume controls plus a separate bass treble and master volume control One of the main features of this remarkable amplifier is its elaborate protection against short and open circuit and we can guarantee that it is virtually indestructable Allied to this is its very high power output 70 watts R M S a frequency response 30 20 000 Hz 3db that is superb and dis tortion that is well below 1 A even at fuil outDut The unit is suitable for use with discotheques roups P A clubs etc or anywhere that high quality high outDut is required Size 15iin x Sin x 6in PRICE 55 0 0 inc P amp P Also available DJ105S 30 watt P A Amplifier Similar specification to above PRICE 35 0 0 inc P amp P DISCOSOUND 70 MAIN AMPLIFIER A 70 watts RMS 8 Ohms High Fidelity power Amplifier which utilises all silicon transistors of modular construction and features full automatic overload protection against short or open circuits Frequency response 20 20 000 Hz 2db The High output is ideally suited for discotheques groups clubs etc or anywhere where reliability and quality are required This unit is the companion model for use with our control pre amp Discosound PRE 4 or can be used with any other high quality pre amp control unit Size 7 x
149. OA47 1 9 prices nett Pes 2N1307 6 9 2N4059 4 matched 18 p BC179 6 OA90 1 3 As recently reviewed in Hi Fi Sound m fame d mu Leo fja n 2N1 2N4061 8 2N1613 6 2N4062 4 3 AF116 8 8 BCI84L 2 8 OA99 3 BAXANDALL SPEAKER aut do mas AMO Miu B GM CU SYSTEM 2N214 2N4286 2 BC212L A202 Designed b Peter Paxandall 2N2218 9 3 2N4289 8 8 AF127 7j BC213L 5j 0C71 5 6 Superb reproduction tor ota iza 2N2270 12 9 2N4291 3 3 AF139 9 8 BC214L 5 8 TIP31A 17 8 Bandes 1 mre io eT eco 2N2484 13 6 2N4292 3 3 AF180 18 8 BCY70 5 6 TIPS2A 28 9 ELAC 150 59RM109 speaker Unit 2N2646 10 9 2N4410 4 9 AF239 9 9 BD121 18 TIS43 10 6 mit 2139 29 nett built 19 8 8 nett E Piu DUE Ur 2N5062 ae AED eo HDI DE ZTX300 3 8 2N292 9N5163 ASY BD124 16 ZTX301 2N2925 4 6 2N5i99 95 ASY98 6 6 BF167 8 6 ZTX302 46 E STEREO AMPLIFIER S A 10 10 2N2926 2 3 2N5195 28 3 B5041 15 BF178 10 6 ZTX303 4 8 Developed from the very 2N3053 5 8 2N5457 9 9 BA102 9 5 BF180 19 ZTX304 8 9 successful SA 8 8 amplifier 2N3054 14 8 2N5458 9 9 BA156 4j BF194 7 ZTX500 5 giving first class stereo 2N3055 16 2N5459 9 9 BA130 4 6 BF195 76 ZTX501 5 amplificatlun featuring separate volume controls for 2N3325 10 9 40250 14 3 BA145 5 6 BFX29 10 9 ZTX502 6 each channel bass and treble controla 10 watts per channel 2N 3663 11 8 40361 12 8 BC107 2 9 BFX84 7 5
150. Poren Making e TIES and you should send for your Electrical Science Electri Inspection Draughtsman COPY now FREE and without al Supply Mining Elec ship Metallurgy Pro obligation Engineering duction Eng CIVIL ENGINEERING AUTOMOBILE ENG Advanced Civil Eng Gen Advanced Automobile Eng Civil Eng Municipal Gen Automobile Eng m e O m AE p dra xt am Auiaimgbile MATTIS E TO B 1 E T 453A ALDERMASTON COURT l anitary Eng Ro ng epair Automobile Diese Haran Wining 3 D brc Automobile ALDERMASTON BERKSHIRE Water Supply Petrol Tech juo aon Garage i i jain Red Please send me a FREE copy of ENGINEERING WE HAVE A WIDE RANGE OF COURSES IN OTHER SUBJECTS IN OPPORTUNITIES I am interested in state subject CLUDING CHEMICAL ENG AERO ENG MANAGEMENT INSTRU eam or career i MENT TECHNOLOGY WORKS STUDY MATHEMATICS ETC i Which qualification would increase your earning power o 5 ee TOT Em Nom anos 40s E B Sc Eng A M SE CEng AMERE RTEB NAME n NA Lue EAM NIMES A M P E AMIMI ARIBA AILOB P M G ARICS l M R S H A M LE D A M l Mun E CITY amp GUILDS GEN CERT ADDRESS wer ee o inc po Trigo ER OF EDUCATION ETC j British Institute of Engineering Technology i 453A ALDERMASTON COURT ALDERMASTON BERKSHIRE WRITE IF YOU PREFER NOT TO CUT THIS PAGE IS THE LEADING INSTITUTE OF ITS K
151. R TESTED SEMICONDUCTORS HAVE A WRITTEN GUARANTEE NO CONNECTION WITH ANY OTHER FIRM MINIMUM ORDER 10 CASH WITH ORDER PLEASE Add 1 post and packing per order OVER SEAS AND EXTRA FOR AIR MAIL DIMMASWITCH Urna rrenan Pemi ARAE DAS G ar ques Laas it fs o hr ep c Po z 3 E CO CE zm d Aum E E m E Se a S E uec s clo EI i cane aan ao ae mr icis s S M s x m Een Ea ae a aT E 5 REX me mu ee q s mc sm SES dom me c x c T CAL TN I A uH a co a s d x dn o nee se ae Cu ute a Xo e Ra uh fous XE Sea eee m 3s ue zs XS dco EIU qu a Ec E f e A o eer oer cetera ea a RE PEER SUN EE 2 s E See XN oe Sm E eee tear M TE RI qe usus ced SCREENS MI oe En s dz c e or UL Ms d y x SE s Ska eee eec Utne GR a oe i ta uec uu cs uel E Ep Eu This is a dimmer of standard size in ivory and chrome to replace modern light switches with out wiring change controls 40 600W 200 250V at 50Hz of ail lights except fluorescents Two models are available with on off switch to control from maximum to zero D5500 2 at 3 12 6d with clockwise or reverse dimming with the switch at full reverse rotation DS500 2 P at 3 18s uses a patented switch giving on off control at any position of dimming Both are available in D I Y kit form at 10 less Fuse protection is available at 2 6d extra Please send C W O to DE
152. R1 401C 10 NKT210 4 2 NKT406 941 OC82 5 40361 9 6 2N2713 5 6 BA112 18 AC188 12 B108 2 6 BF167 5 013T1 10 7 NKT211 39 NKT420 28 11 OC82D 3 40362 11 6 2N2904A 9 9 BA115 1 6 ACY17 5 9 BA111 6 BF173 6 FST3 BAF 5 NKT212 3 9 NKT451 9 11 0C83 4 6 40370 6 2N2905A 15 1 BA130 3 ACY18 4 BAX13 1 6 BF178 10 6 M4J480 20 6 NKT213 4 7 NKT452 9 6 OC84 5 40406 11 3 2N2924 4 BYX10 3 ACY19 4 BC107 2j9 BF179 12 6 MJ481 27 NKT214 3 5 NKT453 6 6 OC123 qi 40408 12 3 2N2926 BYX36 150 2 6 ACY20 310 BC108 2 9 BF180 6 M4J490 22 6 NKT215 37 NKTS6O3F 4 8 OC139 5j 40462 11 3 Green 2 l BYX36 300 2 10 ACY21 3 10 BC109 2 9 BF181 6 6 MJ491 29 5 NKT216 7 6 NKT613F 5 2 OC140 Tj 40467 16 6 2N2926 BYX36 600 3 9 ACY22 3 9 BC113 5 BF184 7 MPF102 8 6 NKT217 9 NKT654F 4 2 OC170 5 40468A T Yellow 2 BYZ10 9 ACY27 3 6 BC116 8 BF185 8 MPF103 7 6 NKT218 6 NKT675 6 8 OC171 6 40602 8 2N2926 BYZ12 6 ACY28 3 8 BC118 5 BF194 3 6 MPF104 6 NKT219 47 NKT676 5 0C200 6 3 26302 3 9 Orange 2 BYZ13 5 ACY29 76 BC125 11 BF200 10 6 MPF105 8 NKT221 7 NKT677F 310 0C201 9 6 2 339A 5 2N2926 EA403 3 6 ACY30 76 BC126 11 7 BF274 NKT11 76 NKT222 6 NKT703 8 7 OC202 18 26371 3 Brown 2 EC401 5 ACY31 4 7 BC134 5 BFX13 5 NKT12 5 5 NKT223 5 NKT713 o OC203 76 2G371B 3 2N3053 4 5 EC402 4 8 ACY34 3 5 BC135 6 BFX29 6 2 NKT32 6 NKT224 3 7 NKT717 5 10 OC204 8 26374 5 2N3054 12 6 EB383 3 6 ACY35 3 6 BC136 B B
153. S A DL66 25 ECL80 7 EZRO 5 6 PCFS0l 9 9 8130 40 UL4l 12 IR5 5 6K25 15 lOFl8 8 98D 9 3 120 DL92 8 3 ECL 2 7 EZ81 5 6 PCF802 9 9 8P4 8 UL84 7j 184 3 9 6L1 12 10L3 8 30C1 6 8 813 75 DL93 4 ECL83 10 3 GY501 15 PCF805 15 SP4l 6 6 UMSO 5 6 185 6 6L6G 7 9 10LD11 10 6 30Cl5 15 8664 15 DL94 6 8 ECL86 9 GZ30 10 PCF806 18 BP61 6 6 UUS 21 IT4 24j 6L18 8 10P13 13 6 30Cl7 10 954 5 8 DL95 7 0 ECLL3S0030 GZ32 10 PCFS08 15 6 BTV280 80 UUT 21 SA4 7 6 6Q7G 11E3 70 30C18 15 1605 6 6 DL96 7 8 EF9 20 GZ34 11 PCL8 7 9 95 UUs 21 3Q4 13 6 6Q7GT 8 6 12AT6 4 9 30F5 17 40994R 87 DM70 8 EF37A 7 HN309 20 PCLS3 10 3 8U25 19 6 UUS 8 3 305 S S 68A7M 7 I2AT7 6 30FLI 15 0763 12 DY8S6 6 EFs9 8 KT36 18 PCL84 8 6 SU2150 19 6 UY21 9 6 384 7 8 68C7 7 2AU6 5 8 30FLI9 19 7193 2 DY87 6 6 EFdi 10 KT61 22 6 PCL85 9 3 T4l 17 6 UYi1 8 6 5V4 19 6 68G7 6 I2AU 5 9 30FLl4 18 6 7475 14 ESSCC 12 EFo0 85 KT66 30 PCL86 9 8 TDh4 8 6 UYs5 6 6 bDRAGY 8 l68H7 3 3 19AX 6 8 30L15 17 A6 96 EA50 3 6 EFB0 4 6 KT81 35 PD500 29 U1o 7 6 VMP4G 17 5U4G 5 6837 6 12BA6 6 30L17 17 ATP4 2 3 EABC80 6 6 EF85 7 KTSl 705 PENA4 20 Ul4 7 6 VPAB 95 5V4G 5 8 68KYGT 4 9 19BEn 6 3 30P4 22 6 ATP 12 BAF42 10 EF8G 8 6 22 6 PENB4 20 Ulo 835 VR105 30 6 6 5Y3GT 6 6 GSLTGT 6 19C8GT 5 30P12 16 ATP 8 6 EB
154. Super 10 RS DD 12 14 WHARFEDALE WMT 1 Matching Transformer 16 HI FI STEREO TAPE RECORDERS AKA 150D AKAI X 360 AKAI X 360D deck AKAI 1710 AKAI 1800 AKAI 1800SD AKAI 4000 AKAI 4000 D deck ALBA R22 Battery Mains 130 339 290 109 900054 BUSH TP 60 Cassette Tape Recorder FERGUSON 3224 Twin Track FERGUSON 3246 FERGUSON 3247 4 track FERGUSON 3244 Stereo 4 track GRUNDIG C200 Cassette 97 18 37 19 GRUNDIG TK 120 Continental 39 5 GRUNDIG TK 124 GRUNDIG TK 144 GRUNDIG 149 Recorder PHILIPS 3302 Cassette Tape Recorder PHILIPS 4302 Twin Track Aut PHIL PS 4307 4 track PHILIPS N4404 4 track stereo PHILIPS N4407 Stereo PHILIPS N4308 44 18 49 19 57 12 89 11 28 7 35 17 49 10 ie ROO e 105 0 MARCONI 4218 Stereo tape TELETON FXB 510D Stereo 52 10 TRUVOX PD 102 Stereo Tape Recorder 114 15 Ample Gar Parking facilities Comet guarantee thatall prices quoted are genuine Allitems offered availabie at these prices at the time this Issue closed for press Comprehensive Hi Fi Catalogue avallable 5 Add 9 for post and packing on al orders under 50 cartridaes 4 Orders over 50 add 12 for Securicor delivery Make chenues Money Orders nayable to COMET 4 0 0 0 0 0 0 6 0 8 0 0 0 0 10 29 19 0 0 6 8 2 6 6 0 0 0 0 0 3 amp 4 15 1 14 3
155. T ALL BRANCHES RS C SUPER 30 MkII HIGH FIDELI Stereo Multiplexer Tuner head using silicon Planar om O O O O O O Transistors Designed for standard 80 ohm co axial EU input Visually matching our Super 15 and 30 amplifiers and of the same high standard of performance and reliability Printed circuitry A quality product at considerably less than the cost of comparable units Factory built 18 gns Or in Teak finished cabinet as iliustrated 21 gns Terms Deposit 0 1 0 and tnenthly payments 2975s Total 224 19 0 Stereo version 29 gns Carr 10 6 extra TY STE FO A M p F F R S C BATTERY MAINS CONVERSION UNITS FACIA PLATE Attractive design jn rigid Type BM1 An all dry bat High Grade Components Specifications comparable with units costing considerably more TRANSISTORS 9 high quality types in each channel OUTPUT 10 Watts R M R continuous into 154 per channei 16 Watts E M A continuous into 32 INPUT SENSITIVITIES Mag P U 4 mv Ceramic P U 35 mV Tape Amp 400 mY Aux 100 mV Mic 6 mV Tape Head 2 5 mV FREQUENCY RESPONSE dB 10 20 000 c p 5 TREBLE CONTROL 17 dB to 14 dB at 10 Ke s BASS CONTROL 17dB to Lo dB at 50 cjs HUM LEVEL 80 dB HARMONIC DISTORTION 0 1925 at 10 watta 1 000 c p s PARTRIDGE BRADFORD 10 North Parade Half day Wed Tel 25349 BLACKPOOL Agent O amp C Electronics 227 Church Street BIRMINGHAM 30 31 Gt Western Arcade sus We
156. Technical Instructions 46 set Working Instructions 88 set Technical Instructions BC 221 Circuit and Notes Wavemeter Class D Tech instr 18 set Circuit and Notes ae 6 0 pjp 9d BC 1000 31 set Circuit and Notes 6 0 p p 9d CR 100 B 28 Circuit and Notes 10 6 p p 1 R 107 Circuit and Notes 7 6 p p Od AR 88D Instruction Manual 18 6 p p 9d 62 set Circuit and Notes 7 0 p p 9d Ciscuit Diagram 5 6 each post free R 1116 A R 1224 A R 1355 R F 24 25 and 26 A 1134 7 1154 CR 300 BC 312 BC 342 BC 348J BC 348 E M P BC 624 22 1475 88 1392 Colour Code Indicator 2 6 p p 6d 52 set Sender and Receiver circuits 8 post free S A E with all enquiries please Postage rates apply to U K only Mail order only to INSTRUCTIONAL HANDBOOK SUPPLIES DEPT PW TALBOT HOUSE 28 TALBOT GARDENS LEEDS 8 a ab dette amp Sees ee NEW MODEL Y H F KIT ME2 i Our latest Kit improved design and performance plus extra Amplifier Stage receives Aircraft Ama teurs Mobile Radio 2 3 4 etc 1 This novel little set wiil give you endless hours of pleasure and can be built in one evening Powered by 9 Volt Battery complete with easy to follow instructions and built in Jack Socket for use with Earphones or Amplifier ONLY 68 P amp P FREE U K ONLY AUDIO 1 3 WATT AMPLIFIER Ready built tested and guaranteed Very attractive Cabinet in black leatherette with light grey front
157. Tel LANgham 8403 MINIMUM CHARGE 2 6 No C O D orders accepted PLEASE NOTE THAT THE VALVES OFFERED BELOW ARE NOT NECESSARILY OF U K ORIGIN i E mB H L94 8 5 U404 ja QA 6 6 6AU6 5j 615 Bi l0FI8 8j EF8 a 1L04 j nae 9 856 27 8 36 11 U30l 20 oa dr SM OF ser e xu 9 First Quality Fully Guaranteed brats 196 Kres FUR prat 1i uot aU OB 6 6 GAWSA 11 6K23 15 8 JOLD1 11 EESTI NIS eet a oS LABORI Gr ESI eg Be ER S C i EL34 10 6 PABCHO 8 PL83 8h UAF42 10 6 QD3 66 REN dec okie gio MAE TUE EL36 8 6 PCB8 18 PLB4 7j UB41 11 ER He M pis AR 14 19ACG 7 8 EL4I Il PCo 8 6 PL302 16 UBC4 9 8 H4 6 BERG We 6 2 IADE 7 BRAND EL42 11 8 PC900 9 6 PL500 15 UBCSI 8j mma ee a tt PA ne aera ELSl 10 PCCRI 7 PL504 18 UBEBO 7 8 RC P Wan mim MS tomer EL83 8 8 PCC8S 8 PL508 17 6 UBF89 7 los 68 RA 4 TE erat ae Tari B ELB 5 PCC88 I2 PL509 30 UBL 10 CT 16 BO WATT 6A EL amp 8 6 PCCH9 10 6 PLa0 18 l hL21 12 its 4 6 BBN ekser ado mace 86 EL E CTRO N IC Vv A LVES kra s6 peciso tir LYM 14 UCO2 8 6 s H SDN iie KT 8 8 12AUT 8 suut Sli 30 DMTO C ECESU 7 EL9u 6 6 PCCROS 17 PMAL 9 UCC8S 8 ines MG COS M RENT pu PERO Ces prone 18j 8124 65 DYTO 15 ECF82 7 EL91 5 PGC80617 PY3L 5 UCFSO 10 6 iit i ond A Ea 107 12A Vi 9 30Cl8 15 813 75j DYR 0
158. Television readers Motorola Semiconductors have announced a range of low cost integrated circuits for the con sumer equipment field Known as MFC units these plastic encapsu lated devices use smaller chips and contain fewer circuit elements than the professional equipment of i c s These new i c s also have wider pin spacing to make them suitable for the printed circuit boards used in consumer products The first two devices in the range to be introduced are a low power audio amplifier and a wide band amplifier The former Type MFC 4000 is a 250mW a f amplifier with a low total har monic distortion typically 0 794 at 50mW output and is designed for pocket radios Contained in a four lead package it includes six transistors three diodes and five resistors and requires no output transformer to match to a 160 load The input sensitivity is 15mV rm s for S0mW output It re quires a 9V d c supply and the quiescent current is 3 5mA The latter unit Type MFC 4010 is a high gain 60dB wide band 100Hz to 4MHz 6dB points amplifier that could be used either as a general purpose a f amplifier or as an i f ampli fier at 465kHz Typical output noise is ImV r m s Maximum power supply potential is 18V and typical current drain is 3ma The retirement was recently an nounced of Hugh Greatorex who for 37 years has been with the BBC Engineering Information Department For the last 16 years he has b
159. U76 49 W4 3508 6 ycua1 12 6 EMA 7 6 M8162 12 6 PL36 9 6 UBFSO 5 0 U78 4 8 DW4 0008 6 ECH35 5 9 EYS1 7 6 ME140014 9 PLal 9 6 UBF89 6 8 u107 18 8 DY86 7 5 9 ECHa42 12 89 EY8L 7 MHL4 12 6 PLSJA 10 6 UBL21 9 Ul91 12 6 DYso 9 6 ECH8 5 9 EYA3 11 MHLD619 6 PL v 6 6 Ucar 5 6 U25l 14 6 E80F 24 ECH83 8 EY84 10j MX40 12 8 PL83 6 6 UCCH4 8 Uzel 8 E83F 24 ECH84 7 8 EY86 7 8 6 NIR 40 3 FL84 6 6 UCC85 7 8 U28 8 E8RCC 12 ECLSO 7 EY88 8 6 NIOS 27 10 PL302 12 UCF80 a U301 11 E180F 18 ECL82 6 6 EYSl 3 N308 17 6 PL500 13 UCH 1 9 Us n0 14 8 E182CC 22 6 ECL83 9 EZ35 5j N339 25 PL504 13 80 UCH 42 eal U403 6 6 E1148 10 6 RCL84 12 EZ40 7 6 Phi 10 6 PL505 28 9 UCH8SI 6 6 0404 7 6 EA50 1 6 ECL85 ll EZ41 8 8 PABCRO 7 3 PL508 27 10 UCL82 7 Us01 19 6 EA78 18 ECL86 8 EZs80 4 j6 PC 10 3 PL509 28 9 UCL83 10 U4020 7 6 EABCAHO 6 6 ECLL800 EZ81 4 9 PCH amp 10 3 PL802 15 UF41 10j VP4B 10 6 EACYL 3 30 EZ90 4 3 PC95 8 2 PMB 7 9 UF42 9j VPI3C 7 EAF42 10 EF22 19 6 FW4 5006 6 PC97 8 6 PY32 3 10 UF80 6 9 VP 3 5 EB34 8 EF36 3 6 FW4 800 PCo00 7 8 PY8O 6 UF85 6 8 VP4 7 6 EBS 4 6 EFSTA 7 15 PCC84 6 3 PY81 5 3 UF86 8j VR 5 24 EB91 8 EF39 5 GZSUu 7 POUR 6 6 PY82 S 3 UF89 6 9 VRI05 6 EBC4L 9 6 EF40 10 GZ32 9 POC 9 9 PY8
160. UR LOWEST 800 12 6 14 18 30 800 80 41000 5 9 3 12 6 50 U9 20 Mixed Volts 1 watt Zener Diodes s 10 UD Cr CU MENU 220 pe PT i r 2 f up each PRINTED CIRCUITS EX COMPUTER 1200 6 6 11 6 15 Uli 30 PNP Silicon Planar Transistors TO 5 sim 2N1132 10j Packed with semiconductors and compo TRIACS Ul13 3 30 PNP NPN Sil Transistors OC200 amp 28104 10 ADI61I NPN nents 10 boards give a guaranteed 30 M 2A 10A Ul4 150 Mixed Silicon and Germanium Diodes 10 ADI62 PNP trans and 30 diodes Our price 10 boards O 1 TO 6 o cu U15 25 NPN Silicon Planar Transistors TO 5 sim 2N697 10 NE FE Bris Jo a Plus apa po e E 109 his 4 e F o Ule 103 amp Silicon Rectifiers Stud Type up to 1 000 PIV 10 GERM POWER TRAN TRANSISTOR EQVT amp SPECIFICA 459 20 25 35j U17__30 Germanium PNP AF Transistors TO 5 like ACY17 22 10 SISTORS For mains TION BOOK German publication v amp ort Blockingveltaze U18 8 6 Amp Silicon Rectifiers BYZI3 Type up to 600 PIV 10 driven output stages of BP ARS o A Ups EU Et nd in either direction U19 925 Silicon NPN Transistors like BC108 10j Amplinete and Radio Japanese Transistors Exclusive to Bi 2N3055 115 WATT SIL U20 121 5 amp Silicon Rectifiers Top Hat up to 1 000 PIV 10 OUR LOWEST PRICE PAK 15 each POWER NPN U21 30 AF Germanium alloy Transistors 28300 Ser amp OC71 10
161. URNS RATIO 1 1 1000 High quality construction Input 230V 50 60 cycles 1 11100 6 Ranges 19 5 Bridge voltage at Output full variable from 0 260 volts Bulk quantities available 1 000 cps Operated from 9 volts 100uA 1amp 45 10 0 2 5 amp 26 15 0 5 amp 9 15 0 Meter indication Attractive 2 tone metal 8 amp 14 10 0 10 amp 418 10 0 12 amp 21 0 0 ense Size T x 5 x 2in 20 P amp P 5 20 amp 37 0 0 336 G W SMITH amp CO RADIO LTD Also see oppos page ARF 100 SIGNAL GENERATOR A F SINE WAVE 20 200 000 c s Square wave 20 30 000 c s HIGH IMP 21V P P600 Q 3 8V P P TF 100 Kc s 300 Me s Variable R F attennatnmii inteat modulation Incopor ates dual purpose meter to monitor AF out put and 94 mnd on R E 2020 2409 A C 32 10 0 Carr 7 6 TE 20D RF SIGNAL GENERATOR Accurate wide range sig nal generator covering 120 Ke s 300 Mc s on 6 bands Directly cali brated Variable R F at tenuator audio output Xtal socket for calibra tion 220 240V AC Brand new with instruc tions 15 Carr 7 8 Size Ido 215 x 170 ntn PEAK SOUND PRODUCTS Aiuplifiers Kits Speakers Ful range af in stock TY75 AUDIO SIGNAL GENERATOR Mine Wave 20c s to 200 kc s Square Wave 20c x to 30kc s High and low iinpedance output Ovt put variable up to 6 volts 220 240 volts A C Size 210 x 150 x 190 mm Brand new with inatruc tions
162. Uganda music at 2025 4990 R Barquisimeto Ven music at 0745 4995 R Brazil Central with football at 2250 5026 Kampala Uganda in vernacular at 1850 6045 R Clube Paranaense Brazil 2300 6055 R Panamericana Brazil at 2235 6250 Santa Isabel Guinea Spanish at 1930 John Trewick of London Colney has a Perdio six transistor portable receiver with a telescopic antenna and a log which includes 6145 Deutsche Welle to the USA a 0435 0555 7210 Oslo Norway on Sundays at 1200 to 1235 11735 Rabat Morocco with news at 1715 11740 ABC Australia with news at 1700 John also reports that a new station is Trans Europe Portugal at 0900 1000 on 9650 and 11720 and at 1345 1415 on 9625 and 11865 The first pro gramme is in English from the Tourist Radio and the second is a relay of Deutsche Welle in English Geoffrey Gilham of London S E 12 is a regular reporter to the column and his log includes 4835 R Mali with talk in French at 2045 4855 R C Mozambique music at 2102 4923 Radio Quito with classical music at 0250 4967 R Kuwait with pop music at 2052 6090 R Belgrano Argentina with talk at 0203 6160 Emis Nueva Grenada Col at 0420 Times 4 Frequencies in GMT in kHz THE BROADCAST BANDS Malcolm Connah Regular reporter Roy Patrick of Derby has sent in some more very interesting news items FINLAND Radio Finland has announced that it intends to drop its DX programme IRAQ Radio Baghdad has been logged on 96
163. Utad Amada Player with the TRANSCONTINENTAL FULLY TRANSISTORISED STEREOPHONIC RADIOGRAM CHASSIS Complete with 2 10 x 6 speakers and the latest BSR Mono Stereo Record Changer a complete radiogram at half normal price ONE Y 10 Watts Total output G P amp P 38 Ens 17 Transistors amp 10 diodes 17 6 EASILY FITTED NO TECHNICAL KNDWLEDGE NECESSARY Credit Terms available First monthly payment 4 9 10 followed by 9 monthly payments of 4 9 10 Total Credit Sale Price 44 18 4 Send 5 7 4 today Callers anatramadas POPU BS cece eee ter rare reco canas inneren M O caleve chs tp se Aga aammtens a COUPON LEWIS SERITUR iii CHASE SIDE SOUTHGATE Dep P10 70 NOW LONDON N 14 TELEPHONE 886 3733 9666 g me uu HE n a Mem O GEN E SER Gud Gad EM for fast easy reliable soldering Contains 5 cores of non corrosive flux instantly cleaning heavily oxidised surfaces No extra flux required THIN GAUGE SOLDER ESSENTIAL FOR solderingsmall components and thin wires High tin content low melting point 60 40 alloy 170ft S A 22 gauge on a d plastic reef Rix Recommended o sa retail price 15 d SOLDER SAVBIT ALLOY ALSO REDUCES COPPER BIT WEAR Ecomically packed for general electrical A and electronic E soldering 75tt he 18 gauge on ea plastic reel Mar ad Recommended na AA retail price 15 ue LO
164. VW C16 2 5uF25VW C26 2 5uF25VW C7 uF polyester C17 250uF 25VW C27 250uF 25VW C8 1uF polyester C18 0 015uF polyester C28 5000uF 30VW C9 1uF polyester C19 10uF 12VW C29 0 25uF polyester C10 500uF 12VW C20 25uF 12VW Semi conductors Loudspeakers Tri BC109 Tr4 AD161 Tr7 BC108 50W Amplifier 2 Goodmans Type 12P 50watt 12in 8 ohm Tr2 BC108 Tr5 BC109 Tr8 BC108 25W Amplifier 1 Goodmans Type 12P 50watt 12in 8 ohm Tr3 BC108 Tr6 BC108 Tr9 BC108 All Mullard Power Module and Supply Power amplifier module Henelec Type PA50 Henrys Radlo Ltd Mains power unit Henelec Type MU422 Henrys Radio Ltd Miscellaneous Transformer T3 Type CP6713 2 Henrys Radio Ltd Transformer T2 240V 17V Type CT1 Henrys Radio Ltd Light Dependent Resistor LDR Mullard ORP12 Lamps 6V 0 04A 2 Batten lampholder MES Dial lampholder MES Neon panel indicator 240V Bridge rectifier MR1 30V Henrys Radio Ltd Type LT 119 or 1H3 Jack sockets 3 Switch S1 1 pole 2 way Henrys Radio Ltd Wafer type A Switch 2 pole 2 way mains toggle Plug and socket 3 pin mains Input Henrys Radio Ltd type 373 Knobs 4 Henrys Radio Ltd type NK2 Knobs 5 Henrys Radio Ltd type 7 Veroboards 3 7 x 5in 5 x 4in 5 x 4In plain 0 1in matrix Screened connecting cable Mains lead 3 core cable gt ee ee es X materials list Chassis and Panel Cabinet Weyroc chipboard 3in Pieces as in Fig 2 Al
165. Various Mullard Thermistors in stock Send 9 6 for new comprehensive catalogue P P tor Components 1 6 per order Cutter 9 Yeropins Bag 50 5 THYRISTORS 1 AMP 50V 5 100V 5 6 200V 7 400V 9 8 3 AMP 50V 6 100V 7 6 200Y 8 400V 10 6 ZENERS 13 WATT 2 7 33V 4 6 10 WATT 3 9 100V 7 6 400m w 3 0 33V 4j 1 Watt 2 4v 200v 7 6 INTEGRATED CIRCUITS R C A CA3005 25 6 CA3011 16 6 CA3014 27 CA3018 19 CA3019 19 CA3020 27 CA3020A 37 CA3029 27 6 CA3026 91 CA3028A 16 6 CA3028B 24 CA3029 19 6 CA3036 16 6 CA3041 25 CAS3049 95 CA3044 27 CA3046 19 6 CA3048 45 CA3050 39 6 CA3052 36 6 FAIRCHILD L900 914 9 6 L923 12 6 L702C 86 6 L709C 21 L710C 21 L716C 56 DATA SHEETS FOR RCA DEVICES 2 PER TYPE G E INTEGRATED CIRCUITS PA230 22 6 PA234 26 6 PAQ37 85 PA246 57 6 Data Sheet 1 PA424 55 Presets std horiz or vert Potentiometers Log Lin Twin ganged Pots Log and Lin MFD V Price MFD V Price 40 j0 25 26 18 200 15 25 50 250 82 15 250 32 3 320 40 400 40 500 50 500 50 SN 640 50 1000 64 1000 80 2000 100 2000 100 2500 100 5 4000 100 4000 100 47 6 195 5000 25 12 6 200 5000 50 19 6 VERBOARD RESISTORS 15 Matrix 1 Matrix 4 watt 595 5d afin 3 6 4 1 watt 10 6d 5in 4 3 4 9 2 5 watt 5 1 6 Bin 4 8 4 9 5 watt 59 5 2 Sin 5 6 5 6 10 watt 5 2 6 Ifin 12 6 4 watt 5 8d 17in 18 21 6 1 watt M O 2 1 9 or
166. Working voltage is 200 250V a c Home Radio stress that they supply a guarantee with these irons and they also stock a com plete set of spare parts any of which can be changed in a matter of seconds The retail price of the Ersa Sprint is 3 19s 6d and the only retail supplier is Home Radio Components Limited 234 240 London Road Mitcham Surrey CR4 3HD The P A R S are again holding a Mobile Rally The venue as in previous years is Kimberley Barracks Deepdale Road Pres ton next to Preston North End Football Ground The date is August 30th and a talk in station will be active on 160m Refreshments both tea and the hard stuff will be avail able Numerous trade stands will be in evidence Further informa tion may be obtained from s a e please G Wright G3YOT 56 Queensway Bamber Bridge Pres ton PR5 6UD The Radio Amateur Invalid and Bedfast Club will have a corner of their stand at the Radio Engineering and Communication Exhibition devoted to the collec tion of unwanted foreign stamps So if you have any stamps please take them along to the Exhibition and leave them at the R A I B C stand Also on this stand visi tors will be able to see at first hand the kind of good work the Club does Both the Hon Sec of the Club Mrs Woolley G3LWY and Allan Herridge G3IDG will be present throughout the exhibition and look forward to meeting Practical Wireless and Practical
167. XTER amp COMPANY ULVER HOUSE 19 KING STREET CHESTER CH 2AH Tel Chester 25883 As supplied to H M Government Depts Hospitals Local Authorities etc DISCOSOUND DJ DISGO AMP DJ DISCO AMP The DJ Disco amp has been designed specifically for use with discotheques and has many exclusive features not normally found on P A amplifiers The unit will be of use to the professional D J as well as in clubs and mobile discotheques The pre amp section features independent inputs and volume controls for two mics with separate bass treble and master volume plus two independent inputs and volume controls for turntables again with separate bass treble and master volume controls A complete Pre fade listen P F L cueing monitor section is also featured with separate input for headphones either stereo or mono with an independent volume control for headphone monitoring and a P F L switch so that either turntable can be monitored fcr accurate cueing up of records A mic over ride switch is also added which cuts the music volume by half so that mic announcements may be made over the music without altering the volume controls The power amplifler section has an output of 70 watts R M S into 8 ohms and has elaborate protection against thermal short or open circuit The unit is designed for panel mounting SPECIFICATION 70 watts R M S Idb at 8 ohms 30 20 000 Hz x 3 db Output power Fre
168. accurately set Ideal for switching on tape recorders Offered at only a fraction of the regular price new and unused only 39 6 leas than the value of the clock alone post antl insurance 2 9 NE L DRILL CONTROLLER Electronically changes speed from approxi mately 10 reys to maximum Full power at all speeds by finger tip control Kit includes all parts case everything and ful instructions 19 6 plus 2 6 post and insurance Mada up model also available 37 6 plus 2 6 p amp p MAINS MOTOR Precision made as used in record decks and tape recorders ideal also for extractor fan blower heaters etc New and perfect Snip at 9 8 Postage 3j for first one then 1 for each one ordered 12 and over post free Run your small transistor radio from the maina ull wave circuit niade up ready to wire into your set and adjustable high or low current 8 8 each AC FAN Sinall but very powerful mains motor with Shin blades Ideal for cooling equipment or as extractor Silent but very efficlent 17 8 post 4 6 Mounts from back or front with 4BA SUDPPWR BALANCED ARMATURE UNIT 300 ohm operates speaker or miero 299 phone so useful in Intercom or similar o cirouits 8 6 ea 83 10 0 doz 209 80 ohm model 8 8 THERMOSTATS Type A 15 amp for controlling room heaters greenhouses alring cupboard Has spindle for polnter knobs Quiokly adjustable from 90 80 F 9
169. aching radio subjects and an unbroken record of exam successes We are the only privately run British home study College specialising in electronics subjects only Fullest details will be gladly sent without any obligation To British National Radio School Reading Berks Please send FREE BROCHURE to NAME er SA is podeis E de e eek cae BP doe mA dl Biock ADDRESS PEA STO me ee cee Toe De d ree de Deren Caps arc GRY RT ct Reg P en PARE tty ID ce OO TO DO 15 GR e Please 1 70 BRITISH NATIONAL RADIO SCHOOL 384 SAVE POSTAL COSTS CASH AND CARRY BY CALLERS WELCOME ECUS3 4 6 EL37 17 3 KT66 17 3 PCL88 15 R20 11 9 U25 18 ECC84 6 8 EL41 11 KT74 12 6 PEN36C15 R52 78 U26 11 9 ECC85 5 6 EL42 10 6 KT G 12 6 PEN45 7 j RK34 7 8 731 6i ECC86 8 EL amp 1 10 KT88 34 PEN45DD BP42 19 6 ECC88 7 EL83 7 6 K TW6112 8 15 sP61 3 3 C33 28 6 ECCI89 9 6 EL84 4 9 KT W6212 6 PEN46 4j TH4B 10 U35 16 6 ECC80412 EL85 8 KTW63 6 PEN453DD TH9 3 7 U37 34 11 ECCR0727 EL8G 8S L63 8 9 19 6 TP amp 20 8 9 U45 15 6 ECF80 6 8 ELO 4 6 LNI52 7 PENAS 19 86 UABC80 6 6 U47 13 piso 9 PCRs 6 8 ELOS 5 3 LN309 10 PEN DD UAP42 10 38 T49 11 9 d ECr86 9 EMRO 7 6 LN319 13 9 4020 17 6 UB41 6 6 C50 5 6 V T ae ECF804 EMBL 7 6 LN339 13 9 PFL20011 9 UBC4L 9 U52 5 6 A de 42 EM84 6 6 LZ329 6 6 PL33 19 6 UBCHI T7
170. adiograms transistors etc STAN WILL ETTS 37 High Street West Bromwich Staffs Tel WES 0186 WE BUY New Valves Transistors and clean new components large or small quantities all details quotation by return WALTON S WIRELESS STORES 55 Worcester Street Wolverhampton WANTED EARLY WIRELESS ITEMS 1900 1920 Outside Horn Hand operated Springless Gramophones Please describe and price wanted T Christen 12 Princess Terrace Brighton 7 Sussex BN2 5JS VALVES AND TRANSISTORS required in new condition Any quantity purchased Quotation by return Langrex 16A Well field Road Streatham S W 16 01 769 0199 WANTED Six Truvox Rank Language Laboratory Pupil Decks in working order Headmaster Maes Garmon School Mold Flints SERVICE SHEETS SERVICE SHEETS 1925 1970 for Tele visions Radios Transistors Tape Recorders Record Players etc by return post with free Fault Finding Guide Prices from 1 Over 8 000 models available Catalogue 2 6 Please send S A E wth all orders enquiries Hamilton Radio 54 London Road Bexhill Sussex a LARGE SUPPLIER OF SERVICE SHEETS T V RADIO TAPE RECORDERS RECORD PLAYERS TRANSISTORS STEREOGRAMS RADIOGRAMS CAR RADIOS l Only 5 each Manuals from 10 plus large S A E Uncrossed P O s please original returned if service sheets not available C CARANNA 71 BEAUFORT PARK LONDON N W 11 We have the largest supplies of
171. agnet assembly 5 10 0 P amp P 7 6 Guitar models 25w 6 0 0 35w 8 0 0 E M I 3tin HEAVY DUTY TWEETERS Powerful ceramie magnet Available in 3 or 8 ohms 15 each 15 ohms 18 8 each P amp P 2 6 12in RA TWIN CONE LOUDSPEAKER 10 watts peak handling 3 or 15 ohm 37 6 P amp P 6 85 OHM SPEAKERS 31in 14 P amp P 2 6 7 X 4in 21 P amp P 4 ee 0 5 M e RA V UOS e VYNAIR AND REXINE SPEAKER AND CABINET FABRICS Approx 54in wide Usually 35 yard OUR PRICE 15 per yard length P amp P 2 6 min one yd 8 A B for samples TT e M E M WESEm MAGNAVOX DESK TYPE MOVING COIL MICROPHONE Medium impedance Brand New Special Price 12 p amp p 2J BALANCED ARMATURE EARPHONE Approx 70 ohm impedance Can be used as ultra sensitive mike or speaker ONLY 3 8 P amp P 1 6 CRYSTAL MIKES High imp for desk or hand use High sensitivity 18 6 P amp P 1 6 HIGH IMPEDANCE CRYSTAL STICK MIKES OUR PRICE 21 P amp P 1 6 HIGH IMPEDANCE DYNAMIC STICK MIKES High sensitivity 38 6 P amp P 2 6 HONEYWELL MICROSWITCHES 8 P C O Push button action Rating 950v AC at 15 amps Size approx 1 x J x iin 5 each P amp P 1 6 or more post free SPECIAL OFFER PLESSEY TYPE 29 TWIN TUNING GANG 400pF 146pF Fitted with trimmers and 5 1 integral slow motion Suitable for nominal 470 k sc LF Size appor 2x1x1 Only 8 6 P am
172. ails of the assembly of the circuit boards and a full components list TO BE CONTINUED Practical Wireless Designers Srcphy 372 Vit CONVERTER author to the importance is attached by the author to the reception in this country of paging stations operating in the United States on frequencies around 35MHz Not from any eaves dropping aspect but as a check on the upward movement of the m u f and the possibilities of reception of signals via the F2 layer WoW Aerial Fig 1 Circuit of the converter Note that C1 C8 and C16 should be wired directly between their respective valve pins and earth Re AS 2 2k0 5W C RA R5 470kn 39k The writer s interest lies with v h f propagation JOMHz and above so with the increased activity in the low v h f band over the past few years due to maximum sunspot activity need was felt to cover this part of the spectrum with something better than a modified RF25 unit The RF25 unit having switched positions gave only limited coverage It had been set to the main paging station frequencies so coverage was inefficient at frequencies removed further than 500kHz from the preset position Accordingly a simple converter was made using commercially available coils giving fully tunable coverage from 26MHz to 53MHz Circuit Basically the unit Fig 1 contains an rf stage using an EF80 or EF184 pentode feeding into an ECF80 frequency
173. and G qualifications preferred NATCS National Air Traffic Control Service 401 Practical Wireless Classified Advertisements The pre paid rate for classified advertisements is 1 8d per word minimum order 20 box number 1 6d extra Semi displayed setting 5 10s Od per single column inch All cheques postal orders etc to be made payable to PRACTICAL WIRELESS and crossed Lloyds Bank Ltd Treasury notes should always be sent registered post Advertisements together with remittance should be sent to the Classified Advertisement Manager PRACTICAL WIRELESS IPC Magazines Ltd Fleetway House Farringdon Street London E C 4 for insertion in the next available issue MISCELLANEOUS mei eee THE NEW ELEGTRONIG MUSIG FOR YOU Then how about making yourself an elec tric organ Constructional data available full circults drawings and notes It has 5 octaves 2 manuals and pedals with 24 stops uses 41 valves With its variable attack you cam play Classics and Swing Write NOW for free leaflet and further details to C amp S 20 Maude Street Darlington Durham Send 4d stamp BUILD IT in a DEWBOX quality cabinet length D E W Ltd FERNDOWN Dorset Write now Right now 2in x 2iin x any Ringwood Road S A E for leaflet PARAPHYSICAL LABORATORY Down ton Wilts Telekinetic photographs data S A E for list Samples 20s 2 WATT TRANSISTOR AMPLIFIERS not a
174. ands Needham Market Suffolk ALL THOSE LITTLE ITEMS which you can never find are available from our stock Also speaker fabrics BAF wadding Peer less speakers cabinet kits cross overs For full details send 9d in stamps to Audioscan mt P W 4 Princes Square Harrogate Orks 402 MISCELLANEOUS continued ENAMELLED COPPER WIRE S W G Per 4lb reel Per ilb reel 18 22 11 3d 16 6d 23 30 11 9d 17 6d 31 35 12 3d 18 6d 36 40 15 24 41 44 17 9d 29 6d Orders despatched by return of post Please add 1 per item P amp P Supplied by Banner je er 84 Old BARES Rd West Didsbury Manchester TRADE ENQUIRIES INVITED SERVICE MANUALS for Pre 1958 H M v and E M I MODELS Radio and Record Player Manuals 5 each Television Manuals 7 6 each Send C W O stating model re quired Also limited range of components and spares Send details of your require ments R D I Ltd Chilton Works Garden Road Richmond Surrey SHURE TAPE HEADS Record playback and erase in one unit Mounted on bracket with tape guide etc 10 post paid MARRIOT Single record playback heads 5 post paid PHOTO ELECTRIC SWITCH KIT Light cell transistor relay etc Elegant case in hammer finish 51 x 21 x 44 fitted with light hood ideal counter alarm Dawn Dusk switch etc 35 Post Paid 6 OR I2 VOLT FLUORESCENT LIGHTS 12 Ine 8 Watt tube ample Ilghtfor caravan t
175. annot accept lega responsibility for It Prices are those current as we go to press All correspondence Intended for the Editor should be addressed to Fleetway House Farringdon Street London E C 4 Address correspondence regarding advertisements to Advertisement Manager Fleetway House EB Eig used London E C 4 Orders for back numbers should be addressed to IPC Magazines Ltd Back Numbers Department Carlton House Gt Queen Street ondon W C 2 NEWS NEWS NEWS When Dixons Photographic en tered the Audio HiFi field in depth their first units were up dated versions of existing record reproducing systems restyled for marketing through the Company s 100 plus Branches under the PRINZ label Now they are marketing their own Prinz Stereo System 6 Spe cific points in the system s speci fication are detailed Amplifier Solid state 12 transistors a c Mains 220 250V 50Hz Fre quency Range 50 18 000Hz Noise level 55dB Controls On Off and Volume Bass Treble and Stereo Balance Output 5 watts Music Power per Channel Turn table is a Garrard 4 speed Auto 2025TC fitted with Acos GP93 1 stereo crystal cartridge with sapphire styli Speakers are two sealed enclosures each containing one 8in x Sin loudspeaker 10 000 lines and complete with 8ft of lead per enclosure ter minating in a 2 pin DIN plug Cabinets are as in photograph with teak veneer finish Price is 55 complete Two Metr
176. ard Sizes with Gusset Plates Sizes to fit Cases All 24 Walls sz qd s d s d 6 x3 6 6 10 x7 10 3 14 x3 8 9 6x4 6 9 12 x3 8 O 14 x9 17 3 8 x3 7 9 12 x5 9 O 16 x6 12 9 8 x6 9 3 12 x8 12 9 16 x10 19 0 Chassis Post 3s Od per order Discounts available on quantities E R NICHOLLS Manufacturer of Electronic instrument Cases 46 LOWFIELD ROAD STOCKPORT CHESHIRE Tel 061 480 2179 gt BRAND NEW ELECTROLYTICS 15 16V 0 5 1 2 5 10 20 30 40 50 100 mfds 8 5d E12 series 5 resistors Carbon Film iW 100 to IMQ 1 5d Wirewound 5W 150 to 15KO0 10d postage 1 The C R Supply Co 127 Chesterfield Rd Sheffield 8 TRANSFORMERS Rewound Prototypes supplied capacity for small quantity runs S A E please Ratcliffe 18 Beech Avenue Thongsbridge Huddersfield Yorks CAXTON COLUMN This is a column cabinet 23 x 54 x Sain deep finished in black or wood grain cloth with blue Vynair front Key hole slot for wail mounting Fitted with three speaker units 9 ohms impedance Handles 8 watts Makes all the difference in quality and volume of tape recorders and record players Real bargain at 59 6d P amp P 11 each SPEAKERS E M I 134 x 8in 3 ohm 45 15 ohm 48 6 P amp P 5 6 E M l 3in tweeter 17 6 P amp P 2 6 E M l 134 x Bin fitted two 21in beato 15 ohm 77 6 P amp P 5 6 E M I 134 x 8 Ins 15 ohm Hi Fi quality 5 19 6 P amp P 5 6
177. at burst and automatic chrominance control circuitry including a pulse generator stage of type which has not previously been used in domestic TV equipment Secondly an account of the various types of tubes that can be used to display colour pictures beam masking deflection and indexing types their advan tages and disadvantages Includes a description of the Sony Trinitron and the Essex tube which could lead to big changes in TV receivers ELECTRONIC VIDEO RECORDING EVR is due to be with us soon and brings with it many new techniques Next month we publish a detailed account of the system with a block schematic and description of a colour EVR teleplayer LOG PERIODIC AERIAL The log periodic aerial offers considerable advan tages where narrow beam width and good front to back ratio are required A practical design will be given together with an outline of the principles of this type of aerial ON SALE NOW D IAE ete QUERY COUPON This coupon is available until 4th September 1970 and must accompany all queries in accordance with the rules of our Query Service PRACTICAL WIRELESS SEPTEMBER 1970 eai nm i INCREASE YOUR KNOWLEDGE Established 1891 MANY COURSES TO CHOOSE FROM incl RADIO amp TV ENGINEERING amp SERVICING TRANSISTOR amp PRINTED CIRCUIT SERVICING COLOUR TV SERVICING ELECTRONICS NUMERICAL CONTROL ELECTRONICS TELEMETRY TECHNIQUES CONTROL SYSTEMS ELECTRONICS
178. bile Picnic 16th Torbay A R S rally at Newton Abbot 16th Mobile Rally at Derby 23rd Wroughton Aerodrome near Swindon RSGB EXHIBITION 1970 PRACTICAL WIRELESS PRACTICAL TELEVISION Visit our Stand at the Show where we shall be glad to meet our readers and their friends WHEN Wednesday Aug 19th to Saturday Aug 22nd 10 a m to 9 p m daily WHERE The Royal Horticultural Society s New Hall Greycoat Street Westminster London S W 1 Nearest Station Victoria HOME RADIO Components LTD Dept PW 234 240 London Road Mitcham CR4 3HD Phone 01 648 8422 Ever had karntafi indaparttie f U B At some time or another most constructors of radio and electronic projects get hit by this complaint The symptoms Depression exasperation headaches Po Weariness sore feet etc The causes Frustrating hours spent in thumbing through inadequate out of date catalogues making numerous fruitless phone calls tramping or touring from shop to shop all in a vain attempt to locate some vital components E Here is the answer to the problem the Home Radio Components Catalogue a world renowned medicine for preventing the complaint or for quickly clearing up the trouble if symptoms have already begun to appear Just send the coupon with 8 6d plus 4 postage amp packing and your copy will be despatched immediately In its 350 pages over 8 000 components are clearly listed over 1 500 of them
179. case Battery d wW j NYE 4 Fig 9 below Final assembly of the pedals and their positioning relative to the contact rail Upper pedal stop rail thick felt 3 wid Pedal g thick feltiapprox 7 wi e movement along front edges UL approx En um Let Lower contacts Upper contacts normally closed Use for F normally open demBrosh Use for keying N TR Lower pedal notes stop rail L i od Pam oe IJ MR M re Contact rail v LO Sm ee REED a pas cp T aiii a M mA eee yr a All poe Contact rail U aluminium channelling 5x X y c GE 73300 Ep E F F G Ab A B B C il NE 24 3 4 OL A RE 7 ig oh 12 pas Del TERES E Ux uu mAn 1 ne n a T i ML s e A er Pry ye ye ya doidas d Fig 10 Details of drilling required to mount contact sets on contact rail s E ee Mount contacts this way On completion of the pedals and contact rail assembly fit felt strips along the front frame mem bers beneath and above the pedals Fig 9 Carefully check the movement of the pedals and that they do not rub against the guide pillars which if necessary can be filed down a little to obtain clearance Check that all contacts operate on downward movement of the pedals ie check actual contact make and or break with a continuity meter Part 2 will give the circuit diagram of the complete unit and describe its functions There will also be det
180. ch receivers with more modern types but not always with complete success Some of the more up to date receivers too are by no means faultless in this respect generally speaking the replacement of certain valves with more modern A types should be attempted only by experienced persons who have access to reliable test and alignment apparatus without such test gear results obtained are likely to be problematical When first class results are required on the higher frequency bands attention should first be paid to the aerial and its aerial matching unit after which the use of a preselector can be considered which can make the best possible use of such signals that are available from the aerial system CIRCUIT Reference to Fig shows the final preselector circuit adopted The components associated with Trl confer the required degree of r f amplification Transistor Trl operating in common emitter mode with the necessary tuned circuit L1 VC1 tied to the base element which allows continuous coverage over the frequency range of 13 30MHz The three principal amateur bands used for DX 10 15 and 20 metres are thus taken care of in the prototype they appear on the dial pointer at approximately the 10 1 and 2 30 o clock positions Due to the damping effect of the aerial preselector tuning tends to be broad and there is thus no need to fit a reduction drive to the peaking control VCI Amplified signals appear at the collect
181. changer Internal coupling between the triode oscillator and pentode mixer is sufficient for frequency conversion to the if of SMHz The output from the frequency changer feeds into an if amplifier prior to feeding into the main receiver By using an if of SMHz the main receiver can be accurately set to SMHz on a standard frequency station before inserting the converter output An alternative circuit is given Fig 2 for using an ECC84 cascode stage No r f gain control is fitted but those readers living adjacent to a channel B1 transmitter may find one necessary to prevent over load Fig 3 Construction The layout of the various components can be seen from the photographs The usual precautions of short direct wiring and single earthing points for each stage should be observed 220V ur CIA f C18 0 005 Tr O 05uF 1 7 2 C16 15pF C19 C20 1500pF 1500pF R9 2k 3W Vis HT C6 Stages 7 7 e a Cs R10 Il 270kQ 90 1 loW 3 2 ae eae V4 ECC84 Aerial C3 100pF 6 P 7 GA R22 Ri Ca RII C22 100 neo 0 005 270 0 005 kn F F Qe Hr wl Fig 2 Alternative rf stage using the cascode circuit The five coils are mounted on a sub panel with shields between the coils The power supply is fed into the unit via a four pin socket but constructors may wish to make their own arrangements in this respect Likewise a suitable dial can be fitted and calibrated after the alignment of the uni
182. coil for this band has 20 turns removed from the tuned winding A rotary wafer switch with three wafers each having 2 pole 2 way sections is fitted under the chassis below the ganged tuning capacitor Connec tions for the coils are as follows Blue 1 and 9 to chassis 8 to aerial via switch 6 to T f grid via switch Yellow 8 to h t positive 1 to chassis 9 to r f anode via switch 6 to mixer grid via switch Red Range 2 9 to chassis 2 to 300pF padder returned to chassis 8 to oscillator anode capacitor via switch 1 to oscillator grid capacitor via switch Range 3 As Range 2 but no padder and pin 3 wired directly to chassis An individual 60pF trimmer is wired across the tuned section of Yellow and Red coils Aerial coils are peaked with the panel trimmer Coverage is of the 160m and 80m bands with a little to spare and the cores and trimmers are adjusted in the usual way P W BINDERS Preserve your copies of Practica Wireless Don t let them become torn and dirty buy a hard cover binder for 18s 6d from Binding Department IPC ei EUG Limited Tower House Southampton Street London W C 2 Price includes post and packing LiND AiR AUDIO E M l COMBINATION LOUDSPEAKERS 131 x 8 elliptical with twin tweeters 8 ohm impedance power hand ling 10W Brand new guaranteed Lind Air Price 89 6 Tm C Overload protec tion 20 000 op 4C volts 10 50 250 1 000v DC volta 3 25
183. communications man and match up tothe qualifications below cut yourself into a slice of Britains future Become a Radio echnician in the fast growing world of Air Traffic Control Please send me an application form and details of how can join the fascinating world of Air Traffic Control Telecommunications Name med ee RT TER te mes tN Address iamen A pectet Not applicable to residents outside the United Kingdom To A J Edwards C Eng MIEE The Adelphi Room 705 John Adam Street London WC2 marking your envelope Recruitment Sending this coupon could be your first step to a job that s growing in importance every year The National Air Traffic Control Service needs Radio Technicians to install and maintain the vital electronic aids that help contro Britain s ever increasing air traffic This is the kind of work that requires notonly highly specialised technical skills but also a well developed sense of responsibility and candidates must be prepared to undergo arigorous selection process Those who succeed are assured a steadily developing career of unusual interest and challenge Starting salary varies from 1044 at 19 to 1373 at 25 or over scale maximum 1590 higher rates at Heathrow There is a good annual leave allowance and a non contributory pension for established staff You must be 19 or over with atleast one year s practical experience in telecommunications ONC or C
184. ctical Wireless axe invited to submit articles for publication and te compete fox the Practical Wireless Designers Trophy RULES Articles submitted for the competition should con form to the general style of material published in Practical Wireless and must describe the operation and construction of a piece of radio audio or test Sogn that has been designed and built by the author Articles should preferably be typed using double spacing leaving wide margins and on one side only of each sheet Circuit diagrams and any other draw ings should be on separate sheets and numbered to agree with the text Author s roughs must be clear enough to permit re drawing Component lists must also be separate and laid out to the standard PW format 3 Photographs of the equipment are desirable and should be in black and white sharp and clear Each photograph should be identified by sticking a Piece of paper on the back rather than by writing on the photograph itself 4 Components used in the design must be readily available from retail sources 5 An entry form properly completed must accompany each article submitted There is no limitto the number of articles submitted by any one author Articles must reach the Editor Practical Wireless Old Fleetway House Farringdon Street London E C 4 by the first post on Monday November 2nd 1970 with the envelope and title sheet clearly marked Project Autumn A stamped
185. d DERBY 26 Osmaston Rd The Spot Half day Wed Tel 41361 DARLINGTON 18 Priestgate Half day EDINBURGH 133 Leith St Half day Wed Tel POT GLASGOW 326 Argyle St Half day Tues Tel CITy 4158 HULL 91 Paragon Street Half day Thursday Tel 20505 340 Einploving Twin Printed Cireuits 200 200v A C mains Operation CROSS TALK 52 dB at 1 000 c p s CONTROLS 5 Position Input Selector Bass Treble Vol Bal Stereo Mono Switch Tape Monitor Switch Mains Switch INPUT SOCKETS 1 P U 2 Tape Amp 3 Radio 4 Mic or Tape Head Opera tion of Input Selector assures appropriate equalisation CHASSIS Strong Steei Approx 12 x 3 x Bin construction plastic silver background black lettering Silver nish matching control knobs as available Eminently suitable for use with any make ot pick up or Mic Ceramic or Magnetic Moving Coil Ribbon or Crystal currently available Superb sound output quality can be obtained by use with first rate ancillary equipment COMPLETE KIT OF PARTS 22 gns Ca IT 26 Point to point wiring diagrams and detalled instructions UNIT FACTORY BUILT With 12 months guarantee 29 gns or Deposit amp and 9 monthly payments 66 3 Total 33 16 3 or in Teak or Afrormosia veneer honsing 82 Gus Carr 15 Terms Deposit 4 and 9 monthly payments of 74 2 Total 287 7 8 Send 8 A E for leaflet 21 236 1279 Wed Tel 68043 MAIL ORDERS TO Henconn
186. d P O for total amount direct to 307a EDGWARE ROAD Dep M YUKAN london wa ae We aupply many Government Departments Municipal WM Authorities Institutes and Leading Industrial Organisations we can supply you too Open all day Saturday Cloned Thursday afternoons ELECTRICAL BEST EVER 200 240 VOLS MAINS SUPPLY FROM 12 VOLT CAR BATTERY Exclusive World Scoop Purchase The fabu lous Mk 12D American Heavy Duty Dyna motor Unit with a Massive 220 watt out put and giving the most brilliant 200 240 volt performance of all time Marvellous for Television Drills Power Tools Mains Lighting AC Fluorescent Lighting and all 200 240 volt Universal AC DC mains equip ment Made at tremendous cost for U S A Govt by Delco Remy This magnificent machine is unebtainable elsewhere Brand New and Fully Tested only 5 9 6 plus 10 6 postage C O D with pleasure Money back if not delighted Please send 8 amp e for interesting illus details Dept PW SCIENTIFIC PRODUCTS Rear Derby Road North Promenade Blackpool Lancashire METAL WORK METAL WORK All types cabinets chassis racks etc to your specifications PHIL POTIS METAL WORKS LTD Chapman Street Loughborough a ge e mama SITUATIONS VACANT RANK WHARFEDALE LIMITED require tester troubleshooters The Company who are leading producers of quality Hi Fi equipment require suitably qualified staff
187. d at the same time make it the most interesting hobby of this day and age Full details and prices are avail able from Bi Pak Semicon ductors P O Box 6 Ware Herts Going Metric A new leaflet Going Metric Everyday Units is now available free from the Metrication Board The leaflet sets out the more common metric units and correct symbols for 14 everyday quan tities including length area cap acity temperature and weight In the United Kingdom the basis for the metric system now coming into use is the Inter national System of Units known in all countries by the abbrevia tion SI The units contained with in this system are sufficient for all present needs of technology science industry commerce and daily life Copies of the leaflet can be obtained without charge from Information Division Dept 4 Metrication Board 22 Kingsway London W C 2 NEWS NEWS NEWS Quick on the draw No it s not a new kind of space gun it s an Ersa Sprint soldering iron Made in West Germany the retailer in this country is Home Radio Ltd The interesting thing about this iron is that it weighs only 7ozs and heats up in only 10 seconds The technique used is different from usual quick heat irons because this switch is released once the operating temperature has been reached Current con sumption is 150W during heat up period dropping to 80W when operating temperature is reached
188. ddress d GO ST A Ts eai a PYE CAR RADIO Push Button Tuning Heart This PRESTOLOCK 5 station Push Button Tuner Heart with Manual Over ride is an idea basis for quality AM car radio Size 64 x 4 x 2 As illustrated but without knobs 25 plus 3 P amp P ELEGANT SEVEN Mk HI 350mW Output 7 transistor fullg tunable M W L W superhes portable Set of parts Complete with all components including ready etched and drilled printed circuit board back printed for foolproof construction MAINS POWER PACK KIT 9 6 extra Price 5 5 0 plus 7 6 P amp P Circuit 2 8 FREE WITH PARTS The DORSET 600m W Output Price 5 5 0 plus 7 6 P amp P i E M Circuit 9 6 AT FREE WITH PARTS 7 tr amp nsistor fully tunable M W L W superhet port able with baby alarm facility Set of parts The lateat modulised and pre alignment techniques makes gt thia simple to build Sizes 12 x 8 x 3in MAINS POWER PACK KIT 9 8 extra QUALITY MAINS TRANSFORMER Input 250 volts OUTPUT All RMS values 4 windings of 11 5 volts con nected in series total 46 volts at 4 5 amps conservatively rated The 4 following combinations may be used 1 73 U 23 volts 2 46 volta Both of these above voltages are commonly used in medium to high powered transistor amplifiers power supplies ete Price 35 plus 7 6 P amp P
189. dge or 2025 TC and the very successful DUO type 2 speakers Measuring 17tin x 103in x 63in the Duo type 2 speakers are beautifully finished in _ teak veneer with matching vynair grills They incorporate a 10tin x 6 in drive unit and high frequency speaker both of which are of 3 ohms impedance The Duo speaker system is also available separately at 6 6 0 each plus 15 p amp p Signal to noise ratio 70db on all inputs with vol max Controls 6 position selec tor switch 3 pos stereo and 3 pos mono Separate volume controls for left and right channels Bass 14db at 60 Hz Treble with D P S on off 12 db at 10 KHz Tape recording output sockets on each channel Size 12tin 6in 23in in teak Complete stereo system 41 plus 2 10 p amp p High fidelity transistor stereo amplifier employing field effect transistors With this feature and accompanying guaranteed specifications below the Viscount F E T vastly surpasses amplifiers costing far more finished case BUILT amp TESTED MkII MAG P U 15 15 plus 10 p amp p Specification same as Mk 1 but with the following inputs Mag P U CER P U Tuner Spec on Mag P U 3mV at 1 kHz input impedance 47K Fully equalised to within 1db RIAA Signal to noise ratio 65db vol max r Duetto integrated transistor stereo Amp 9 10 6 7 6 p amp p CONTROLS 4 position selector TONE CONTROL Treble lift and cut Garrard Changer from M pn p amp
190. dimension for concert hall originality Two controls adjust volume and reverberation Simply plug microphone guitar etc in and the output into your amplifier beautiful walnut cabinet 74in x 3in x 44in 10 4 0 plus 6 P P amp Ins VOX SWITCH This sound operated switch is ideal for mobile TX work tape recorder You speak it switches EH AF take off point In kit form with Ideal for all Supplied in a Just attach your In kit form High Listen Easily built Driver The set of three ONLY For lists only send in NEW VALVES Guaranteed and Tested IRS 5 6 185 4 3 1T4 2 9 384 5 9 8V4 5 9 6 30L9 11 6 6AQ5 5 68N7GT 4 Q5L8GT 4 6 30C18 12 0 30FL1 12 6 30FL12 14 8 30L16 12 9 30P4 11 0 30P19 11 9 30PL1 12 6 30PL13 14 8 30PL14 14 CCH35 13 CL33 17 6 DAC32 6 9 DAF91 4 2 DAF98 7 DF33 7 6 DF91 2 9 DF96 7 DE32 6 9 DK91 5 6 DE92 8 8 Postage on 1 valve 9d extra 24 HOUR SERVICE DK968 7 3 EL84 4j9 PL84 6 DL35 4 9 EY 51 7 PL500 12 9 DL92 5 9 EY86 6 8 PL604 13 8 DL94 5 9 EZ80 4 8 PY32 10 DL96 7 3 EZ81 4 6 PY33 10 DY86 5 3 KTol 9 3 PYS 5 DY87 5 3 KTee 16 6 PY82 5 EABC80 5 9 N78 17 PY83 5 6 EBC33 7 9 PC86 10 3 PY88 6 6 EBC4l 9 3 PC88 10 8 PY800 7 EBF89 6 PC97 7 9 PY801 6 9 ECCS 3 6 PC900 7 R19 6 3 ECC82 4 PCC84 0 8 U25 12 9 ECC83 4 9 PCC89 8 11 U26 11 6
191. dio Engineering and Communications Exhibi dun cor Radiocom 70 have taken note of this change of CONSTRUCTIONAL ate it is now August 19 22 For full details please refer to page 360 We hope many readers will be there Practical Vibrasonic 25 50 Guitar Amplifier Wireless will have the usual display of constructional b asd AN 348 projects on show Ban reselector eue all this zo ty ANY Aulo Fair Eo BUS on in by A S Carpenter G3TYJ 355 ctober Once again Practical Wireless wil be supporting the exhibition with displays and demonstrations of a range ius anam Meter of audio projects plus a special competition for the y d gums 363 occasion It is all a little feverish for those intimately con Car Aerial Signal Booster nected with the trade and the technical press by P Hand 364 With the RSGB exhibition so far as P W is concerned Organ Pedal Bass Unit our participation is very largely a matter of preaching to by A Lester Rands 368 the converted yet we think it well worthwhile to take part L Band V H F C Anything that encourages a greater interest in home con ow ban H F Converter struction meets with our approval and the RSGB exhibition by R Bunney 373 has always stressed this side of the hobby This year we Take 20 Multimeter Extras are pleased to learn that small stands will be available to by Julian Anderson 376 non trade members of the Society to display and sell I C of the Month Motorola MFC Bliss ou ee Me pan 4000P Audio Ampl
192. dspeaker To add to the simplicity only four leads connect the silicon monolithic chip to the outside world d c power supply signal input and output and a common earth The unit is the first of a series of consumer circuits intended for the amateur con structor and for manufacturers of utility equipment such as portable radios and baby alarm or inter com units Fig 1 Equivalent circuit of the MFC 4000P As such it does not match the G E series of audio integrated circuits introduced to our readers in March 1970 P W or the increasingly familiar Plessey SL403 which are essentially hi fi devices with internal noise levels 65dB or more down or with less than 0 595 total harmonic distortion On the other hand those devices require feedback and decoupling connections to the chip with multiple pins and an external metallic heat sink Further previous audio units required a d c supply L A J IRELAND Motorola MFC 4000P Audio Amplifier higher than the 9 volt battery which powers the standard pocket radio or domestic transistor device the MFC 4000P on the other hand will operate at full rating down to 6 volts d c though with the harmonic distortion raised to 4 due to crossover difficulties At a nominal 9 volts a harmonic distor tion figure of 0 7 is attained a better performance than is common in the standard pocket radio preamplifier driver and class B output lineup Actual size of the MFC
193. e 1 9 Complete Untested 17 T V Sets 12 Channel 50 Carr l VALVE LIST EX EQUIPMENT 3 months Guarantee Single Valves ARPI2 1 6 PCC84 2 PL36 EBS 9d PCF80 2 PL8I EBF89 3 PCC89 3 PY81 ECC82 3 PCL85 5 PY800 ECL80 6 PCL84 4 PY82 EFI83 3 PCL82 4 PY33 EFI84 3 PCFs6 4 UI9I EY86 4 PCL83 3 6F23 5 16B8 1 6 4 68VV7 2 6 1 6 6U4 4 3 6 20DI 3 1 6 20Pl 5 5 20P3 2 6 4J5 3OPLI 5 4J 30PI2 4 6 130F5 2 9 405 E WEYRAD COILS amp TRANSFORMERS FOR CONSTRUCTORS Special versions of our P50 Series are now available for AF117 or OC45 Transistors They can be used in the standard superhet circuit with slight changes in component values Oscillator Coil 1st F Transformer 2nd I F Transformer ard I F Transformer I F TRANSFORMERS FOR PRACTICAL WIRELESS CIRCUITS Components for severa receivers are available including the following for the Clubman T41 1E mauetiftsmuauuasusttmeuumueeueo Rod Aerial Driver Transformer Output Transformer Printed Circuit request with 4d postage please WEYRAD ELECTRONICS LIMITED SCHOOL STREET WEYMOUTH DORSET VALVES SAME DAY SERVICE NEW TESTED GUARANTEED 1R6 185 1T4 384 3V4 DAF91 DF91 DK91 DL92 DL94 ROUES 7 6 UBF80 5 9 L85 9 UBF89 6 9 PCL86 Ae Dn 7 PCL amp 8 amp POL800 16 6 U PENA4 8 6 PFL20011 9 PL38 9 9 PL81 9 3 PL82 6 6 PL83 6 6
194. e 1922 N 1922 experiments were being made with radio receivers im cars and there follows a description of one of the first car radios The receiving apparatus used is a Marconiphone 6 valve set five of the valves being high frequency amplifiers and the other a rectifier The valves are of the special low current consumption type The aerial is fitted on the roof of the car and is sq constructed that it can be raised and lowered at will by means of a hand wheel Ihe receiver is bedded in spongy rubber and mounted in a compartment under the floor boards immediately in front of the rear seats Control is effected by means of three levers in the car interior PRACTICAL WIRELESS QUERY SERVICE Before using the query service it is important to read the following notes The PW Query Service is designed primarily to answer queries on articles published in the magazine and to deal with problems which cannot easily be solved by reference to standard textbooks In order to prevent unnecessary disappointment prospective users of the service should note that a We cannot undertake to design equipment or to supply wiring diagrams or circuits to individual requirements b We cannot undertake to supply detailed information for converting war surplus equipment or to supply circuitry c It is usually impossible to supply information on imported domestic equipment owing to the lack of details available d We regret we are unable to
195. e RNC SUED F A L P A AMPLIFIERS PHASE PHASE B A E for leatiets 50 20 GNS 100 59 cus NEW HANDY TIDY I N T E R L O C K I N G Newest neat st system ever devised for storing smali parts and components resistors capacitors diodes transistors etc Rigid plastic units interlock together in vertical and horizontal combinations Transparent plastic drawers have label slots removable space dividers Build up any size cabinet for wall bench or table top BUY AT TRADE PRICES SINGLE UNITS Sins x 21ins x 2tins Usually 2 6 each Our Price 24 dozen DOUBLE UNITS Sins x 4 ins x 24ins Usually 4 6 each Our Price 40 dozen PLUS QUANTITY DISCOUNTS Orders 5 and over Deduct i in the Orders 10 and over Deduct 6 in the Orders 20 and over Deduct 2 in the RCKIRRIROStAEA RUE ane Add 6f to all orders under 3 Orders 3 and over packing postage carriage free Quotations for Larger Quantities On VEROBOARD the Universal Wiring Board obtainable from your local Retailer Trade enquiries lo NORMAN ROSE ELECTRICAL LTD Technical enquiries to VERO ELECTRONICS LTD Industria Estate Chandler s Ford Hants multi drawer storage units ORVET Dpt PW9 31 ALBERT RD A place for everything IVORYET HENDON LONDON NW4 Everything in its place 8 St Chad s Place Gray s Inn Road
196. e Vertical Two metre mobile enthusiasts will be pleased to hear of a new antenna manufactured by the American company Antenna Specialists Co and available from KW Electronics Ltd 1 Heath Street Dartford Kent This is a vertical whip the ASP 629 which offers a gain of 2 5dB relative to a quarter wave antenna It consists of a stainless steel whip and matching trans former assembly and may be tuned up anywhere in the range 130 174MHz 346 The interference suppression ratio relative to a quarter wave antenna is better than 6dB The mounting hole required is iin in diameter and no access is needed from the inside of the vehicle The antenna could also prove suitable for a home station and would be extremely useful where space was at a premium The cost of the ASP 629 is 3 10s Antenna Specialists also manu facture vertical whip antennas suitable for 4 metres and 70cms New Inverter A new range of Inverter Modules introduce a new service by Gardners Transformers Limited of Christchurch Hampshire England The new range known as the M48 E H S Series are the product of a development and manufac turing service which has been set up to cater for individual requir ments and special applications They offer power ratings up to 30 watts stabilised or 50 watts un stabilised in a standard mechani cal assembly which will meet a wide variety of electrical para meters The assembly incorp
197. e features 1 A patented brush system which automatically cleans Stylus after each record playing and 2 at shut off the pick up locks itself into its recess other features include pick up height and stylus pressure adjustments and motor suitable for our 230 240 or for 115v continental malns Beautifully styled this is a high class expensive instrument but you can purchase one this month for only 59 6 plus 8 6 post and packing One point these changers have been to France and back and the vibrations of the journey etc may have loosened screws or otherwise put them out of adjustment How ever with each we supply a 16 page service manual and fauit finding chart which i8 80 detailed that if necessary you could completely re build the changer So this is truly amp bargain that you will not want to miss so order today Where postage is not stated then ordera over 5 are post free Below 5 add 2 9 Semiconductors add 1 post Over 1 post free B A E with enquiries please ED A SPECIAL SWITCH eaf Contact Very slight pressure closes both contacts 1 8 each 12 doz Plastic push rod suitable for operating 1 each 9 doz i ELECTRIC CLOCK WITH 25 AMP SWITCH Made by Sniith s these units are ar fitted to many top quality cookers to control the oven The clock is mains driven and fre quency controlled so it is ex tremely accurate The two small dials enable switch uu and off times to be
198. e recessed beading around the front and back of the amplifier compartment and the recessed batten around the speaker compartment It is not absolutely necessary to line the speaker compartment with felt but this may be worth doing to ensure no resonance effects whatsoever from the cabinet Half inch thick carpet felt glued around the inside and on the back panel would be sufficient The cabinet must have strong carrying handles one each side as these will be the only means of carrying it with ease The base of the cabinet can be fitted with rubber feet or two battens crosswise as can be seen in the photos or with roller castors The actual finish of the cabinet can be left to the constructor s choice but the prototype shown on the front cover was covered with plastic material as used for home decorating the cabinet being finally edged at the front with 3 x iin aluminium angle fixed with chromed instrument head screws The loudspeaker cut outs are as shown in Fig 3 If the 25 watt version is to be constructed only one speaker will be used but if the second speaker and therefore higher output power is anticipated for a later date then cut one hole for the single speaker in the top left hand corner as in Fig 3 Otherwise a single speaker may be mounted centrally if desired Construction Amplifier Chassis The amplifier chassis occupies most of the area of the amplifier compartment and allows plenty of room for the three circuit boa
199. e two separate phase shift audio oscillators Resistor values used in each are identical but capacitors differ The output is fed via a crude attenuator to outlet socket SK1 blocking capacitors C4 and C5 being chosen to offer similar reactance at the differing output frequencies Switch S1 offers four alternatives and when at position 1 the unit is Off At position 2 the output should approximate to 1000Hz whilst at position 3 2000Hz signals are available Both tones are available when position 4 is selected The output amplitudes are equalised by preset potentiometer VR1 If necessary resistor R11 may also be a preset potentio meter but this has not been found necessary The purist might consider it an advantage however to make both VR1 and R11 2k preset potentio meters with capacitors C5 and C10 connected to the respective sliders thereby introducing a degree of waveshaping Dissimilar output amplitudes can also be equalized by making either R4 or R9 partially variable A very useful instrument in a very small space 393 Construction The oscillators can be accommodated on a piece of Veroboard measuring approximately 33 x iZin with O lin matrix and ten conductor strips are required Considerable thought has been given to the layout and due to this little preparation of the Veroboard is required Looking at Fig 2 it is seen that after cutting a piece of the board to suit it is only necessary to cu
200. e type 0C71 Tr5 Tr6 Tr7 Amato Tr8 Dai d do mrs di a E A as Rear view of unit shows above the circuit boards with the battery compartment to the right and below the spring mounting of the pedals 368 auccm mtd ow UII unit mains powered but there is no reason why this should not be done The main note generator is a multi vibrator the output of which provides the 8ft pitch notes The pitch for 16ft is obtained from a divider driven from the multi vibrator Then follows the voicing circuitry the output of which is taken through a buffer amplifier and via a volume control to the output socket The maximum signal level available at the me Slot for e PAS contact bar RS 7 o Front Material Planed soft wood Rear pedal support rail Underside view Front pedal stop rail lower output is approximately 1V r m s The drum brush circuit consists of a three stage white noise generator and filter the output being controlled by a special attack decay circuit control amplifier The drum brush signal is then attenuated to balance with the pedal bass output and passed to the buffer amplifier Pedal Frame and Case The basic pedal frame complete with the thirteen pedals mounted and sprung can be obtained ready made from Henrys Radio Limited see materials list The frame has a plywood top cover which is not required as a case to house the circuit
201. e with Strut stand switch and 2 leads with 2 5 and 3 5 plugs 12 6 1 3 Lapel or hand with clip 8 8 1 CM70 Machined metal tapered stick type with neck cord and adaptor to fit standard fioor stands 28 6 1 6 DYNAMIC Crean hand table 15 6 1 5 M810 50K 34 rin with Base Adaptor 37 6 2 6 MS11 similar but fixed on flexible Swan neck to witch fitted base 42 6 2 6 CARDIOD DYNAMIC OMNI DIRECTIONAL Highly successful BALL type 209 50K 600 ohmzsinip 6 6 0 O Uni directional ball type switch cord adaptor DM160 3 17 6 both these types 5 MICROPHONE INSERTS Diameter 1 76in or 0 9in either size 5 6 1 SPEAKERS lin round fitted Tweeter 6W 3 or 15 Q state which 87 8 3 6 or for stereo 80 per paid charges paid Jiu 30 7 6 1 Limited quantity powerful 24in PM transistor replacement speaker high ohms excellent 5 8 1 HEADPHONES Stereo Dyn 8 16 Q 63 3 EARPIECES with lead and min jack plug magnetic 1 8 Crystal 4 9 np to 3 for 1 on either State if 2 5 nim of 3 6mm plug required Crystal 3 5mm only AERIALS CAR TYPES Telescopic vandal proof locks retracted 2 keys and all fittings 27 8 2 6 Superior type slightly longer 30 2 5 Extended Aerials for Portables 9 F M Sets 4 section 61 23 sliding threaded base needs hole 4 6 section 54 254 screw hole in base 4 7 section 54 32 screw hole in base 6 6 10 section 6 471
202. e won t attempt to describe this further but make sure that the resistor is a high wattage type and if used on the mains that careful insulation is used we don t want to lose too many Take 20 readers HIGH RESISTANCE RANGE Many of the cheaper meters have very inadequate resistance ranges the centre scale reading is usually only 3k and it is practically impossible to get an accurate reading over 50k9 The additional com VR1 Ry T ve see text see text Meter on lowest current range o Ses JE o ve Fig 3 A high resistance range can be added to nearly all test meters by using the above arrangement on the lowest current range ponents in Fig 3 will improve the best resistance range by a factor of 10 Again we use the meter on it s lowest current range and instead of the integral 1 5V battery we use an external 15V one B154 or similar The combined resistance of VR1 and R should be 15kQ for a 1 0000 V type and 300k0 for a 20 0000 V meter so for the former type a 12kQ resistor and a 5kQ pot should be used n Number 11 N presenting this month s integrated circuit there is the question of whether or not it would fit more appropriately in the Take 20 slot since the unit in question the Motorola MFC4000P costs little more than l and to date is probably the simplest unit to use In a package occupying less than 1 100th of a cube inch it provides a 1 watt audio amplifier matching a 16 ohm lou
203. ecorder to its higher Correct speed And none of the class protested although one did telephone the next day to say What was that piece you played just after the interval HENRY Es dl No 71 The Facer Faced Chicken wire and wood batten Such a contretemps can happen to anybody In the wireless world it happens even to the boffins A little while ago the British en gineers at the Gloucester factory of Bang amp Olufsen were instruc ted by their parent factory in Denmark to make one or two modifications to a stereo tuner amplifier to cure viups Their radio wizard made the changes and noted an improvement in stability especially at the top of the medium wave band A message went off to Den mark Viups cured what are they please And the answer returned from the Danes Isn t it obvious That s the sound the receiver makes when the fault is present And it was By the same token Henry s new FET IC tuner has a fault best des cribed as Fizzz crick Hhhh But the trouble there is very simple Jargely mechanical Henry is patiently waiting for Gordon King or one of his colleagues to publish another of those reveal ing articles in Practical Wireless which show how an effective loft FM aerial for stereo multiplex FM reception 80 miles from the transmitter in the shadow of a hill can be constructed from a bale of chicken wire and a few lengths of wood batten 389 PROJECT Pra
204. ed all day Wednesday SURPLECTRONICS 216 LEAGRAVE ROAD LUTON BEDS RADIO SURE COMMUNICATION HANDBOOK over 22 000 copies sold Now in its second printing The standard work in its field 832 pages of everything in the science of radio communi cation The handbook s UK origin ensures easy availability of components 69s post paid en Amateur radio circuits book by George Jessop G6JP Second edition reprinted 1970 Designed to meet the needs of the home constructor and experimenter A comprehensive collection of up to date circuits covering a wide variety of applications 13s 4d post paid THE VHF UHF MANUAL By George Jessop G6JP A complete manual for frequencies above 30 MHz Covers aerials receivers transmitters and test equipment The first book of its kind outside the USA 23s post paid Obtainable from RADIO SOCIETY of GREAT BRITAIN 35 DOUGHTY STREET LONDON WCIN 2AE FREE LISTI FANTASTICALLY POPULAR ron BUMPER FLOG X JASON TAPE TECHNICAL m TRADING range recording chara as top grade tapes Quality control manufacture They are truly worth a few more coppers than acetate sub standard jointed or cheap imports TRY ONE AND PROVE IT YOURSELF Standard Play Long Play 3in 150ft 2 3 3in 225ft 2 9 Ain 300ft 4 6 His nre ine Sin 600ft 716 in ta PSALCER AT ALC Sin 90t 10 6 f Skin 12006 13h in t in 5 i BRANCHES Double Play
205. ed end Amber Works with any mono or stereo amplifier Input required 0 2 watts A C mains operated Size 18 x 18 x 4in 12 10 0 ALL EAGLE PRODUCTS SUPPLIED AT LOWEST PRICES ILLUSTRATED EAGLE CATALOGUE 5 BARGAIN AM TUNER Medinm Wave Transistor Superhet Ferrite aerial 9 volt BARGAIN DE LUXE TAPE SPLICER Onis trims joins for editing and repairs With 8 blades BARGAIN 4 CHANNEL TRANSISTOR MIXER Add musical highlights and sound effects to recordings Will mix Microphone records tape and tuner 59 16 with separate controls into single output 9 volt i BARGAIN FM TUNER 88 108 Mc s Six Transistor 9 volt Printed Circuit Calibrated slide cet tuning 9 10 0 Walnut Cabinet Size 7 x 5 x 4 ditto a cabinet 7 10 0 FM STEREO MULTIPLEX ADAPTOR For above or general use Ready made with 4 transistors 99 6 6 diodes 69 6 Post Free 79 6 22 6 BARGAIN 8 WATT AMPLIFEIR 4 Transistor ARADIO BOOKS yr Postage 8d Practical Radio Inside Out Practical Stereo Handbook Supersensitive Transistor Pocket Radio Radio Valve Guide Books 1 2 3 or ea 5 No Sea T V Fault Finding 405 625 lines Transistor Communication Sets Wireless World Radio Valve Data Transistor Circuits for Radio Controlled Models Valves Transistors and Diodes equivalents Manual Coil design amp construction Hartley on Hi Fi Radio Tuners 2 Circuits tor Micro Alloy transistors Practical Car Radio installatio
206. eeeeh wseooonerost uunsEbuda 9enocoss E RRRSRRATRATT E 99999989299 FERRE SETTERS Pee A te ES25 watts Fitted with 1 8 bit intercharigeable bits 3 32 3 16 and 1 4 availabie ideal for high speed production fines For 240 220 110 24 ox 12 volts 36 E P ET V enclose cheque P O cash value E F40 watts Fitted 5 16 bit a 3 Es do i Interchangeable bits 1 4 3 16 1 87 3 32 19 Watts 40 volts s NAMES ae ae i haaa senao a AE PT J available Very high temperature iron For Fitted with nickel plated bit 3 32 and in j 240 220 110 24 or 20 volts 47 0 handy transparent pack From Electrical 34 ADDRESS erre ereneererencererern E Spare bits and elements for all models and Radio Shops or send cash to Antex Pwa and voltages immediately available f i i B ts oteo9Quantto tie 99R9RREPE T3799 7 427 9929995 993 9 95 0D 44 E il J H i L f E z E E E z Ma o a O O O SN 397 Fully guaranteed Open 9 12 30 1 30 5 30 p m Thursday 9 1 p m Hes MANY OTHERS IN STOCK include Cathode Ray Tubes and Special Valves U E Orders DAR packed up to 10 1 10 to 41 2 over 1 2 per 1 over 3 post free C O D 4 extra ALVES TRANSISTORS ZENER DIODES etc CY31 7 j ECL86 8 6 PC97 9 3404A5 2 6 0C29 15 0C172 7 6 3FR5 6 0 AFl118 10 CR83 20 10 DAF96 7 9 Eee 7 P le WM 3x dete an OC200 6 3N128 17 6 AF139 10 CR83 30 11 6 0C201
207. een Assistant Head of that department During this time his responsibilities included the organisation and management of the BBC technical enquiry stands at exhibitions and conferences He made significant contributions to the promotion of new BBC services in particular the v h f radio service and latterly the u h f and colour TV services Hugh has been a great friend of the Press for many years and we at Practical Wireless would like to wish him all good luck in his retirement Do it yourself A new inexpensive educational aid to learning and teaching ele ments of logic Boolean algebra and fundamentals of digital com puters COMPUKIT 1 has been announced by Limrose Electron ics It is supplied in kit form ready to be assembled on a speci ally designed printed circuit board Logic circuits are constructed by making soldered or solderless connections to the terminal pins mounted on the p c board Logic levels are indicated by miniature wire ended bulbs on the board which is powered by a 41 volt battery The gates in the kit use transistors diodes and resistors and can be used not only for per forming elementary logic func tions but also for wired or bi stable and polyflop circuits and counters The kit is complete and requires only a small soldering iron and a pair of cutting pliers to assemble These can be pur chased from the manufacturers as optional extras The Instruction Book is written by a
208. ef OA4UY TR8MC XEIAE XEITX YN2OM YVSCOM 3V8AV 6WSBD 7X2AL 9X5AA Listening on 21MHz Douglas had the distinction of hearing King Hussein of Jordan callsign JY 1 N Richardson Bucks sent in a 144MHz log obtained using earholes backed by a Garex converter into a PR30 and CR7OA tuning 28 30MHz The antenna is an eight element Yagi at 28ft Signals received from EI2AX P G3JQA P G8BCL G8BEU G8BMC G8CAF G8CIL GSCSI G8CVK P GW3GIZ P GW3SRT P GW8ACG P GWSBIP GD2HDZ Isle of Man Nicholas will have a rotator on the Yagi by the time you read this E will put the antenna clear of the chimney and roof G3QG is located at Luton Hoo and is active on 144 68MHz Bill would appreciate any DX reports on his signals and will QSL for worthwhile details of his signals How about it all you 2 metre sleuths A reminder to listen for GB3WRA operating 160 10 from the 24th Annual Wycombe Show on Saturday September 6th If you can get along visitors s w s and licensed amateurs will be welcome Perhaps a chance to go mobile Another one to listen for is G2DRT who will be operating as EIZVCL from September Sth to 22nd from Fenit County Kerry Operation will be on 2 metres Happenings in August include August 9th D F qualifying even at Chelmsford 10th 2 metre s s b contest 15th and 16th 4 metre c w contest September Sth and 6th v h f NFD Mobile Rallies August 9th Woburn Abbey 9th Stratford upon Avon Mo
209. ehensive kit of high grade parts with three coils covering 80 178M Hz 9v battery etc together with simplified diagrams and instructions Price complete 4 post packing and insurance paid direct from makers S A E for literature JOHNSONS RADIO St Martin s Gate Worcester WR1 2DT PADGETTS RADIO STORES OLD TOWN HALL LIVERSEDGE TEL HECKMONDWIKE 4285 Amplifier Unit Type Al413 Com plete with Valves Type 5Z4 and 6V6GT 230 250 Volt 50 Cycles Transformer Clean Condition Untested 25 Carriage B R S 15 Airmileage Units Complete with 24 Volt Motor and Gears etc less Relay Clean Condition Untested 15 Carriage B R S 12 Panel with two Miniature Relays and one Carpenter Relay with Base Ex units 7 6 Post Paid Panels of Resistors and Condensers Ex Equipment 8 per doz Post Paid AW43 80 TUBES Reclaimed With 6 months Guarantee 25 Carriage 15 AW43 88 T V Tube Reclaimed with 6 months Guarantee 2 Plus 15 Carriage MW43 69 30 Plus 15 1 Carriage Speakers P M All 3 OHM Perfect Con dition Ex T V Sets P P on any Speaker 4 5 Round 3 6 x 4 Elyp tical 3 7 x 4 Elyptical 5 Slot Speakers 8 x 24 3 Silicon Rectifiers 500 M A 800 P I V 2 6 or 24 per doz Post Paid JAP EARPIECES Magnetic 8 OHMS Small or Large Plug 1 1 Post Paid TOP GRADE MYLAR TAPES 7 Long Play 14 7 Standard l1l 6 5 Long Play 10 5 Standard 7 9 Post on any Tap
210. el The tremulant control amplifier Tr4 which is an ADI61 must be mounted on a small heat sink as will be shown in Part 2 The mixing pre amplifier Tr8 and Tr9 completes the pre amplifier section and the output from this is taken via VR8 the master volume control to the power output module The pre amplifier power supply T2 the bridge rectifier MRI and the smooth ing capacitor C28 are mounted directly on the main chassis More detailed information concerning tbe pre amplifier and tremulant circuitry its function and performance will be given in a later article Next month will deal with the layout of the three circuit boards the front panel controls and the power module and its supply TO BE CONTINUED E Project Autumn ENTRY FORM E a a a RE SE ONT educ MEA I a La a ME T lcu aa ide O Ra d If my article does not win a prize I should like it to be considered for publication in the usual Way il b to be returned to me Blanatute 15 2 0029 p E Daten ms zi Delete as required Rules on page 390 PA PW 9 354 NEXT MONTA IN PRACTICAL WIRELESS TRANSISTOR AND DIODE TESTER This unit is the first of a new range of test equipment full constructional details of which will appear from time to time in PW Simplicity of construction is the key note of this tester which will measure the basic characteristics of most PNP or NPN transistors Allthe components are mounted on t
211. ency choke and conden ser dividing network The high fre quency unit has a critically curved cone and also uses a high flux ceramic magnet Also EMI 450 SPEAKER our price 65 plus 7 6 carr PEAKER iem teak cabinet size 14 x t0 x 6 Orlginally designed for use with our Countdown stereo budget system but now available separately SINCLAIR Project 60 rm SAVE nearly 6 Normal price 24 18 0d GA NEMUS 006 Designed for building into plus plinths etc complete with 19 10 two 230 Output stages carr 20 watt and power supply unit Send S A E for full technical brochure SINCLAIR 2000 AMPLIFIER save6ons Our price 23gns SONOTONE Cartridges Fitted Diamond Styli Ceramic list price 82 Sensitivity STA BomV AHC 55mV cm sec 41 6 rms minimum at 45 at plus 1 000Hz measured on 216 Decca SXL2057 Magnetic cartridges Diamond styli 95 plus 2 6 p amp p Today s value 6 Stylus replacement can be carried out without removing cartridge Fully guaranteed Ronette 105 Stereo cartridge Sapphire 78 Dlamond LP 25 2 6 p amp p p amp p J J FRANCIS WOOD GREEN LTD 123 ALEXANDRA ROAD HORNSEY LONDON N 8 Tel 01 888 1662 342 When in LUTON BEDS you must visit the SELF SERVICE RADIO COMPONENTS SHOP Serve yourself from a selection of 1 200 boxes of Manufacturer s surplus stocks and save money 9 am to 5 30 p m every day Clos
212. ent etc Fully transistorlsed low battery drain Unbeatab e at 65 6 post pald er In kit form 51 6 4 WATT GRAM AMPS Volume and tone controls mains opereton 3N output new and boxed 12 6 ER PAID SALOP ELECTRONICS Callers welcome 23 Wyte Cop Shrewsbury Shropshire S A E for lists i a MUSICAL MIRACLES Drum Cymbals Waa Waa and Fuzz modules New unique effects es Percussion etc Good waa waa kits 49 Famous Mister Bassman bass pedal unit Also bargain components list of reed switches etc Send S A E NOW D E W Ltd 254 Ringwood Road Fern down Dorset Lc eed SS Se Sy b AERIALS eee BAKER AND BAINES BBC dipole 30 H 42 3 ele 89 ITA 3 ele 26 5 ele 34 8 ele 47 5 11 ele 37 6 ITA doubles 8 ele 12 If ele 140 13 ele 159 Combined BBC ITA D 5 45 D 8 52 H 5 69 X 5 75 Combined Loft Special D 5 with loft pole and fixings 37 UHF Annals BBC ITA 14 ele 37 I8 ele 54 22 ele 63 Double 22 ele 142 CO AX low loss at t 3 and 2 3 Co Ax plugs 1 4 Diplexers Triplexers Matched UHF VHF Diplexers VHF UHF Pre Amps 75 Poles Lashings Clamps Couplers etc Postage Paid inland on aerials Extra on acces sories Please state channels when ordering 1 Dale Cres Tupton Chasterfield FOR SALE _ m me dm mm tn a MADE MORSE a py FACT NOT FICTION If you start RIGHT you will be reading amateu
213. ent takes the form shown in Fig 3 a but when it is used to check a crystal the form changes to that of Fig 3 b This is because the g d o frequency becomes locked to that of the crystal once the crystal is oscillating and th tuning of the g d o is ineffective over a small range and its frequency is precisely that of the crystal Y o 9 o z IT c lorc ER RENE Frequency Frequency a b Fig 3 a Grid current of g d o when used conventionally as in Fig 1 b grid current when used to excite crystal The g d o frequency and hence that of the crystal can now be measured on a receiver in the conven tional manner Depending on the degree of accuracy of measurement required the calibration of the receiver should be cross checked against a standard crystal calibrator with 1MHz 100kHz 10kHz and possibly 1kHz check points It should be remembered that in practice the precise operating frequency of the crystal will depend upon the type of circuit in which it is used If it is necessary to order a crystal for a specific frequency from a manufacturer the type of circuit to be employed should be stated Notes The locking effect mentioned above between the g d o and the crystal is very marked but if it is not obtained during the initial tests the coupling between the coils should be increased by sliding the g d o coil further into the crystal coil It is important to begin with the g d o on its lowe
214. ental frequency of this crystal with a receiver can lead to false answers because of the several spurious signals that can be generated due to the beating together of oscillators in the receiver and the fundamental and harmonics of the crystal under test Fortunately there is a simple way by which the fundamental frequency of any crystal can be found quite accurately before a final precise measurement is made Conventional use of GDO All that is required is a Grid dip Oscillator or g d o This will normally have plug in coils and a roughly calibrated scale for each range It should be stressed that this calibration is really quite rough since the coil is subject to outside influences that can seriously affect the frequency at which the g d o will oscillate In normal use the g d o is loosely coupled to the tuned circuit being investigated and then tuned until grid current shown on its meter suddenly dips Fig 1 The g d o is then moved away from the tuned circuit to reduce the coupling until a good clean sharp dip is obtained on the meter The g d o should if possible be placed with respect to the tuned circuit so that it does not have to be held in the hand It is at this point that the signal from the g d o 366 ARTHUR DOW can be picked up by a nearby receiver and its frequency determined This is only an approximate answer since the frequency of the g d o is being measured and not that of the tuned circuit itself
215. er Lane Leeds 13 No C O D under 1 Terms C W O or C O D Postage 4 6 extra under 2 5 9 extra under 5 Trade supplied S A E wlth enquiries Branches open all day Sats MAIL ORDERS MUST NOT BE SENT TO SHOPS Audio House tery eliminator v E TOES Size 5 x 4 x i 2in approx Completely replaces batteries sup plying 1 6v and 90v where A C mains 200 250v 50c s is available Complete kit with diagram 59 9 or ASSEMBLED 69 9 pum mE ee Tm SUPER 15 HIGH FIDELITY SOLID STATE AMPLIFIER Approx as Super 30 but single channel Complete kit with full constructional details and point to point wiring diagrams 124 gms Carr 12 6 OR FACTORY BUILT 15 Gns Carr 12 6 Terms Deposit 4 Gus and 9 monthly payments 31 1 Total 18 3 9 Available in Teak ot Afrormosia veneered housing 18gn5 OYSTICK SHORT WAVE AERIALS AND TUNERS AT ALL BRANCHES S A E for full list 32 High Street Half day Thurs Tel 56420 LEICESTER 5 7 County Mecca Arcade Briggate Half day Wed Tel 28252 LEEDS 73 Dale St Half day Wed Tel CENtrai 3573 LIVERPOOL 238 Edgware Road W2 Haif day LU Tel LONDON 60A Oldham Street Half day Wed Tel CENtral 2778 106 Newport Rd Haif day Wed Tel 47 D 1629 MANCHESTER MIDDLESBROUGH 096 Al Blackett Street Opp Fenwicks Store NEW UPON Half day Wed Tel AUN CASTLE 13 Exchange Street Castle Market Bldgs Half day Thursday Tel 20716 TYNE SHEFFIEL
216. er for any frequency between IOk Hz and 870 M Hz full details from Imhofs or your local Eddystone agent A DISTRIBUTORS Dept PW7 i 112 116 New Oxford Street London WC1 Tel 01 636 7878 Se l M amp B RADIO 38 BRIDGE END LEEDS 1 Telephone 0532 35649 YHE FM MW LW C TRANSISTOR RADIO Ww s BRAND NEW 10 tran Sistor plus 4 diode table cm model of well known British manufacture The highly polished wood cabinet speaker and pre assembled chassis are supplied seParate and only require fitting to gether and the 2 speaker connections making pit CHASSIS amp CABINET d Pot rue 9 10 0 SPEAKER DO a E ES A ES mcum carr paid m ns STC STEREO MONO HEADPHONES Brand new lightweight high quality comfortable padded headphones for sterco or mono use Weight 10 oz 20 c s to 20 Kc s 300 ohms per earpiece Supplied with details of SEE 12 VOLT TRANSISTOR INVERTERS 12vdc input 270vdc at 150mA case 1 in x 2tin x 4in Weight 150z 65 plus 4 pp TRANSISTOR MODULATOR PRE AMP PANEL BRAND NEW 4 transistors plus 1 diode 4gin x 23in Fitted with pre set microphone gain control and mod filter Originally used to drive an NKT404 which drove a pair of NKT404s Supplied brand new c w circuit of complete modulator 22 6d plus 1 6 pp TRANSISTOR AUDIO AND MUTING PANELS Brand new set of 3 panels Audio panel with transistor gate originally used to drive an NKT404 output
217. etrieal detlectoin Green face medium persistence 7N 926 r Sj AFYI9 22 6 OC42 8 6 PRICE 8 0 0 p p 5 2N2926 0 8 AFZIL 9 OCH 4 2N9996 y 8j ASY26 6j OC45 8 6 uN9 996 g 5 8 ASY27 Qe OG l a d 8 792 2N3086 19 ABY29 003 76 MULTIMETERS DETECTOR DIODES N3133 7 ABYo4 6i OC75 5j JN3391 je ABY74 18 ocs By TYPE MFI6 1X 3 2N3391 74 j IS E I irem RAE qe 2N3392 3 2 ABYT 7 OC7BD 3 3 De Notasi Tinge ata nad Ae LS Osca an For 2N3393 2 6 ASYB 4j OCH 4 6 0 0 5 10 50 230 500 V IN69 4 6 GEXo4 2 OA90 2 2N3304 9 6 ARYRS 4 6 OCBID 3j MORS RES dur e a er OM EIE 2N3305 8 6 BCLOT 3 OC83 4 6 0 10 50 250 500V IN483 2 8 GEXSO01 4 3 0393 P N O Bi BClOR 3 oai 5 Dl trons AAYII 2 8 OAS 3 SM fe 2N3403 5 j RCI99 4j OCI39 7 6 5005 10 100114 rd EST aces sd peers utl 2N8404 6 6 BCLIA 8 6 OCI40 9 6 Remi amp tanee ranges 100MQ IMQ The edd dx ax Ae ess un 2N3414 4 BCIIR 8 8 OCITO 5 meter is also calibrated for capacity and ee TR ser d Pra c i 2N341 4 3 BC147 4 8 OCITI 5 6 output level measurements Sensitivity EET NOM PASE NUES mu cs 2NS4l amp 4 6 BCld8 3 2 O 20n 4 4 200041y Agcuracy 4 LBA for D C am Men euet Meee ois m eum 2N34l 6 2 BOIS 3 6 OC20 10 E AGO ed Cu sas ci ia We TVA A Sia Ape 2N3702 4 6 BC159 3 2 OC202 18 Diuieusionx 44 x 31 x 1 in Price 4 5 0 SNAM Mr ULCUS 2N3 03 3 10 BCITA
218. ey flnish with double spring headband ONLY 63 Post 10 Post 3 6 AT LASKY S BUDGET PRICES C amp 0 7 6 each post 1 35 post 2 85 post 3 C90 12 8 each post 1 57 6 post 2 115 post 3 C120 17 6 each post 1 85 post 2 165 post 3 207 EDGWARE ROAD LONDON W 2 Tel 01 723 3271 33 TOTTENHAM CT RD LONDON WiP SRB Tel 01 636 2605 Open aii day 9 a m 6 p m Monday to Saturday 109 FLEET STREET LONDON E C 4 152 3 FLEET STREET LONDON E C 4 Open all day Thursday early closing 1 p m Saturday Tel 01 353 5812 T l 01 353 2833 AUDIO DEVELOPMENT AD 76K Haskv s Kadio Limite HIGH FIDELITY AUDIO CENTRES i 42 45 TOTTENHAM CT RD LONDON WiP SRD Tel 01 580 2573 Open all day 9 a m 6 p m Monday to Saturday 118 EDGWARE ROAD LONDON W 2 Open all day Saturday early closing 1 p m Thursday ALL MAIL ORDERS AND CORRESPONDENCE TO 3 15 CAVELL STREET TOWER HAMLETS LONDON E1 2BN Tel 01 790 4821 DIGITAL CLOCK e MADE ESPECIALLY FOR LASKY S BY FAMOUS MAKER MAINS OPERATION 12 HOUR ALARM e AUTO SLEEP SWITCH EN e HOURS MINUTES AND SECONDS READ OFF e FORWARD AND BACK e SHOCK AND VIBRATION WARD TIME PROOF ADJUSTMENT BUILT IN ALARM e SILENT OPERATION BUZZER SYNCHRONOUS MOTOR E This unique DIGITAL CLOCK is now available EXCLUSIVELY FRO
219. g and research laboratories Little routine work good opportunities to exercise initia tive excellent holidays Salary scales Tech nician 1 060 1 428 supplementary allow ance for approved higher qualifications Junior Technician 581 869 with paid day release for further study Apply stating and age qualifications experience and present salary to Administrative Assistant P1 Birkbeck College Malet Street London WCIE 7HX TV and Radio A M LE R E City amp Guilds R T E B Certs ete on Satisfac tion or Refund of Fee terms Thousands of passes For full details of exams and home training Courses including practical equip ment in all branches of Radio TV Elec tronics etc Write for 132 page Handbook FREE Please state subject BRITISH INSTITUTE OF ENGINEERING TECH NOLOGY Dept 137K Aldermaston Court Aldermaston Berks EDUCATIONAL BECOME Technically qualified in your spare time guaranteed diploma and exam home study courses in radio TV servicing and maintenance T T E B City and Guilds etc highly informative 120 page Guide free CHAMBERS COLLEGE Dept 857K 148 Holborn London E C 1 CITY amp GUILDS electrical etc on Satis faction or Refund of Fee terms Thousands of passes For details of modern courses in all branches of electrical engincering clec tronics radio TV automation etc send for 132 page Handbook FREE B LE T
220. gue tied mug ically commentary by with Mullard chips and when one chap persisted he was asked in what sphere these plug in whatsits were to be found It turned out that he was a ship board electronics engineer Oh that explains it said Mr Nichol son I Cs on the igh seas Henry often wishes he had the gift of turning away the awkward question and dissolving his audience in friendly laughter When things go wrong at one of his lectures he can be a tongue tied mug Only last week there was the most appalling faux pas The occasion was a lecture on recording and a number of musical illustrations had been taped For the purposes of demonstration these were at different speeds and as is usual with one of Henry s lectures time had us all by the forelock A complicated chart had to be drawn on a rickety blackboard demanding the utmost concentra tion both to prevent the latter falling and the former degenerat ing into illegible graffiti Henry craftily set the trusty 2000 in motion as he drew and drew Minutes later as a man dredges up his consciousness from dream land Henry became aware of something vaguely wrong The horns of the New York Philhar monic had never sounded like that no not even in Mahler s day I am ashamed to say that with out blinking an eyelid our villain said Let s go on to the third movement and while winding the tape forward slyly switched the tape r
221. he cover of a die cast aluminium box which itself provides an elegant finish SIMPLE MINI ORGAN This interesting project which can be builtin a few hours will provide many more hours of entertainment for the constructor and family alike The circuit uses four cheap transistors to produce a musical range of two octaves the notes being selected by a magic wand ELECTRONIC DIGITAL COMBINATION LOCK A device which began life as a gadget to raise funds at a coffee party was developed into this sophisticated version which although amusing could have commercial possibilities The two tran sistor circuit employing digital techniques need hold no fears for the average con structor PLUS THE REGULAR TAKE 20 AND LC OF THE MONTH FEATURES AND OTHER CONSTRUCTIONAL ARTICLES AND FEATURES Don t miss your copy of the Octo ber issue of Practical Wireless on sale 4th September price 3s 6d A S CARPENTER G3TYJ HE simple transistorised preselector to be described can be constructed and got working in a single evening It costs approximately 2 to build and is a worth while project for listeners who like to search out DX on the h f amateur bands Some of the communications type receivers in use function well on the low frequency bands but do tend to become insensitive at higher frequencies of say 21MHz or so Some operators aware of the problem have gone so far as to replace the older octal based valves used in some su
222. he path from Europe to Australia is open why don t more of us hear VK AX stations on forty Perhaps it s still the operator that counts and not so much the equipment Malcolm Monro Cumberland writes a sad tale of holding a G8 licence but the transistor transmitter won t work Two metre fans will be pleased to hear of the latest Fairchild transistor the MSA8506 which gives 25 watts at 175MHz from a 12V line Twist in the tail is the price which is around the 15 mark However the MSA8507 gives 8W for the same parameters and costs around 6 With luck the price should drop as production quantities build up These devices will however withstand any non oscillatory load from an open to a short circuit at full rated power 360 Back to logland again Andy Crooks Leicester RAI PR3O and 45ft end fed prowled 21MHz to find sigs from CP5PD CR6BF CR6FP EL2L EP2BQ HPIRC JAIDJL JA2QUQ JA3QKU JA4DGG JASBMK JHIECU LJ2L special prefix for Norwegian schools LU2CF LU4DM ODSBZ PY2CRN PYSATL PY7GAH TG9GF VE7DG VP2VI VQ9RK Seychelles WSDL W5GC W7RI ZP5GS ZS3HX 3V8AL 5ZACK 9J2PV 9Q5WV All these using s s b D Browning Herts CR7OA PR30X 37ft of bent wire in the loft shows what s been about on 35MHz Heiroglyphics scribed in his log read AX6HD CTIBH CTIGD CT2AK DL5YA MM PR PYIHA 4UIITU 9HIK 9HICC On 14MHz Douglas bagged AXOLD CN8HL CN8MJ HV3SJ HK4AD KL7BJW LUSNA OJ DX Market Re
223. iate credit terms available T DORCHESTER size 16 x LI x Yin appr T Range 45 15 000 c p s Rating 8 10 watts Cone spkr Imp 3 or 15 ohm 7 Carr 7 6 STANWAY ll size 20x108x93in approx Rating 10 watts Including 18x8in speaker with highly flexible cone surround long throw voice coil and 11 000 line magnet PCIE cmt Pera Arr al Lapin ce Lan Recon q GATED os uerus alisti id output e Playing Consisting of matched 12in 11 000 line 15 Watt 15 ohm remisie sound utm 16 Gns ne high quality Arakere eros OT unit and tweeter Smooth R S C TA6 6 Watt HIGH FIDELITY SOLID c ndo ensure suprisingly realistic reproduction 5 15 0 ST STATE AMPLIFIER 3000 A T60 OR SENIOR 15 WATT INC HF126 15 000 Carr 5 9 M 200 250v AC mains opersted AP925 etc line 16ohm Speaker 28 15 0 Carr 6 6 O Pu tS ID AC Dia 3 gns P e mie c p s 24B Harmonic Distor AVAILABLE WITH a dec CI i vas tlon 0 89 at 1 000 c p 8 TRANSPARENT HI FI SPEAKER ENCLOSURES Teak or Afrormosia GMT TS Separate Baa and Treble PLASTIC COVER gns veneer finish Modern design Acousticaliy lined All sizes approx Carr b per enclosure JES Size 16 x 11 x Qin Pressurised Gives 4 14 6 pleasing results with any Rin Hi Fi speaker ui dd SES For optimum performance with any 8in 5 15 0 Hi Fi speaker Size 22 x 15 x 9in Ported alla SE 2 pistaning resulta RU For Salt tien with In w n Fi sp Fi speaker an weeter
224. ical term is really justified Heinrich Hertz born in 1857 became a pupil of the famous physicist von Helmholtz and received a good grounding in electricity as far as the state of the art permitted at that time Although dying in 1894 at the early age of 36 Hertz was able to carry out many experiments that had the most far reaching effect on man s attempt to communicate at a distance In 1888 Hertz had progressed enough to be able to demonstrate the propagation of electromagnetic waves or Hertzian waves as they were then known thus confirming the earlier theoretical work of Maxwell Hertz showed that the waves conformed to the same laws as applied to the propagation of light namely that they could be bent and reflected Earlier experimenters had noticed spurious effects in the vicinity of large spark coils when they were operating such as secondary sparking between metal objects completely isolated from the coil N cu that the name of Hertz has come into Among those experimenters was Edison who coined the phrase etheric force to explain away the effect of secondary sparking at a distance Hertz s receiver consisted of nothing more than a length of wire formed into a circle leaving a minute gap at the ends across which a spark would jump when Hertzian waves were induced into the loop from the nearby spark coil transmitter Hertz found that he could increase the effective range of his equipment by adding metal
225. ifier Until fairly recent times most radio amateurs built all BIS their station gear Nowadays the more general thing is to by L A J Ireland 377 use commercially built transmitters and receivers Whether Transmitter Receiver for the L F this is due to that mysterious phenomena of having more Bands Further Notes leisure time than ever but less time to spare for building by F G Rayer G3OGR 386 or merely to being more affluent is hard to calculate Two Tone Tester But if amateurs cannot or will not build their own main BAS IG ter G3TYJ 9 equipment then they can learn one lesson from the P W Fer n DICE 393 stand That a that there are very many qualliary pieces of equipment that anyone can find the time to build not only Pham 43 a OE directly connected with the radio amateur station but in OTHER FEATURES the various allied fields of radio audio and electronics S pe CNCEN Cau Ez W N STEVENS itor Project Autumn Entry Form 354 Checking Surplus Crystals by Arthur Dow 366 OCTOBER ISSUE WILL BE PUBLISHED Going Back ON SEPTEMBER 4 by Colin Riches and Arthur Dow 381 IPC Magazines Limited 1969 Copyrightin all drawings photographs and articles published In Practical Wireless Is fully protected and reproductlon or Imitations in whole or In part are expressly forbidden All reasonable precautions are taken by Practical Wireless to ensure that the advice and data given to readers are reliable We cannot however guarantee It and we c
226. ig 2 are in accordance with the enclosure space required by the loudspeakers for proper loading and for full 350 Fig 4 Constructional and drilling details for the amplifier chassis and panel Note that the aluminium angle plece at the rear of the chassis is turned downwards while the side and front angle pieces are facing upwards The sizes of the component mounting holes shown in the front panel may need to be altered to suit the components actually used Check before drilling panel All fixing 48A It 7 6 holes CHASSIS PLATE 18 swg aluminium nuts and screws FRONT PANEL 18 swg aluminium aS Es B 2 sa 2 le 2 seo pl 2 E Large holes dl l J 34x 4 aluminium angle j 215 gt 74 MAINS indicator T 4 lt j Small holes EN 4BA ciear ON OFF switch Ag hole 218 sles ae GSE ICE 5 8 te 2 bass response down to about 40Hz It is made from iin thick Weyroc chipboard with joints strengthened by 2 x lin planed battens All joints must be screwed as the cabinet is carrying a fair weight when the speakers and amplifiers are installed and because strong joints will prevent cabinet buzz at very low frequencies Weyroc is hard to cut but most local timber dealers with a power saw will cut the pieces exactly to size as in Fig 2 One may then only have to cut the holes for the speaker s Fig 2A B and C give all the cabinet assembly details Note th
227. iin 1 200ft D P mylar 15 Es jin 1 200ft L P acetate 12 6 MODEL TE 10A ii a Volt 5tin 1 200ft U P mylar 18 5 25 50 250 500 2 500 D C ofin 1 800ft D P mylar 22 6 10 50 100 500 1 000 v A C Sin 2 400ft T P mylar 39 8 0 504 A 2 0mA 250mA D C Tin 1 200ft std acetate 12 6 0 6K 6 meg ohm 20 to 7in 1 800ft L P acetate 15 22dB Tin 1 800ft L P mylar 20 10 0 100mFd 0 100 0 1uiFl Zin 2 400ft D P mylar 25 69 6 P amp P 2 6 in 3 600ft T P mylar 45 Postage v Over 3 post paid SAVE UP TO 335 TAPE CASSETTES OF HI FI EQUIPMENT Send for discount price list Top quality in plastic library boxes C80 60 min 8 6 3 for 24 6 C90 90 min 12 6 3 for 36 C120 120 min 15 3 for 43 6 Cassette Head Cleaner 11 8 Post Extra CETHA IRADO J LTD 3 LISLE STREET LONDON W C 2 Tel 01 437 8204 34 LISLE STREET LONDON W C 2 Tel 01 437 9155 311 EDGWARE ROAD LONDON W 2 Tel 01 262 0387 OPEN 9 6 MONOAY TO SATURDAY EOGWARE ROAD 12 DAY THURSDAY 337 DEPT D 222 224 WEST ROAD WESTCLIFF ON SEA ESSEX BIPRE PAK LTD TELEPHONE SOUTHEND 0702 46344 FULLY TESTED AND MARKED AC107 3 0C170 AC126 2 6 OC171 AC127 3 6 0C206 ACI28 2 6 0C201 AC176 5j 26301 ACY17 3 2G303 AF114 4 2N1302 3 AF115 3 6 2N1304
228. in instructions Carr 7 6 1 3 ae 500 Kc s 10 Mc s ternal batteries g ns up to 30 Mc s oH Attractive 2 harmonics tone case 74 Calibrated dial TRIO JR 310 New Amateur Band 10 80 x 5 x 9 Metre Receiver in stock 77 10 0 Power require Price 17 10 0 ments 300V D C Carr 3 6 LAFAYETTE SOLID STATE HA600 RECEIVER l mA and 1 Y 5 BAND AM OW BSB AMATEUR AND SHORT D C 0 34 VATE 150 pede Kc s and o Ke s 30 Mc s Excellent condition 88 8 Carr 7 6 ront end amp 2 mechanical filters Huge dial Product detector Variable BFO TE 40 HIGH SENSITIVITY oise limiter amp S meter O 24in Bandspread 1 230V A C 12V D C neg earth operation O RF A C VOLTMETER gain control Size l in x 94in x 8iin Weight 1s 10 meg input 10 ranges de JM bU VALUE 245 Carr 10 Am liy UE BIMA TORO Ai J s lt S A E for full detaila R N S 4cps I 9 Me s dition 5 19 6 Carr 7 6 a Decibels 40 to 50dB Or brand new with acces Suppli 1 s 3 pplied brand new complete sories 7 19 6 Carr 7 6 LAFAYETTE HA 800 SOLID STATE with leads and instructions AMATEUR COMMUNICATION RECEIVER m CLASS D WAVEMETERS No 2 gir bands 3 5 4 7 7 3 14 14 35 21 21 49 28 99 7 60 54Mo s Dual conversion on atl Operation 230V A C 17 10 0 Crystal controlled 1 2 19 Mc s Mains or bands 2 x 455 Kc s mechanical filters FET front end product detector variable BFO I oJ 12V D C ope
229. in ferrite rod aerial for Medium and Long Waves Retractable 4 section 24in chrome plated telescopic aerial for peak Short Wave listening Socket for Car Aerial Powerful push pull output Seven transistors and two diodes including Micro Alloy R F Transistors Famous make 7 x 4in P M speaker Air spaced ganged tuning condenser Volume on off control wave change switches and tuning control Attractive case with carrying handle Size 9 x 7 x dit approx Easy to follow instructions and diagrams make the Roamer 7 a pleasure to build Parts price list and easy build plans 3 FREE with parts Personal Earpiece with switched socket for private listening 5 extra de Total building costs 5 19 6 pocket five MEDIUM WAVE LONG WAVE AND TRAWLER BAND PORTABLE WITH SPEAKER Attractive black and gold case Size 54 x 1 x 3kin Tunahle over both Medium and Long Waves with extended M W band for easier tuning of Luxem bourg etc 7 stages 5 transistors and 2 diodes supersensitive ferrite rod aerial fine tone moving coil speaker Easy build plans and parts price list 1 6 FREE with parts Total building costs AA P amp P 3 6 roamer six SIX WAVEBAND PORTABLE WITH 3in SPEAKER i RADIO EXCHANGE CO a E 61 HIGH STREET BEDFORD M NEW trans eight SIX WAVEBAND PORTABLE WITH 3in SPEAKER Attractive case in black with red grile and cream knobs
230. inal v f o box using easily obtainable components and giving correct coverage for both 160m and 80m with the minimum of difficulty There are three 1 silver mica capacitors and the coil is a Denco Clacton Ltd Yellow Range 3 It is mounted inside the box with the threaded rod protruding So that all circuits can be screened the holder for the EF91 was mounted on the box and thus encloses all the components in Fig l The r f choke is a miniature cored type as used in transistor receivers 386 TRANSMITTER RECEIVER It is only necessary to adjust the core of L1 until coverage is from 1 75MHz to 20MHz with a little to spare at the extreme settings of the v f o tuning capacitor For 160m the dial is calibrated from 1 8 20M Hz For the 80m band frequencies from 1 75 1 9M Hz are doubled giving coverage of 3 5MHz to 3 8MHz Buffer and PA Fig 2 shows the switching of the buffer amplifier and p a circuits S1 is a single pole 2 way rotary wafer switch mounted under the chassis below the v f o tuning control L2 is for 160m and is a Denco Blue Range 2 coil with the small coupling winding wholly removed L3 is for 80m and is a Denco Red Range 2 coil the small winding being removed and 28 turns taken off the tuned winding These coils are under the chassis with the threaded rods above The switch S1 is set for 160m the v f o tuned to about 1 9MHz and L2 core peaked for best pa grid current W
231. ipment books etc drop us a line and we ll put a note in the earliest available issue This pholograph shows a Daimler car equipped with a Marconiphone receiver and frame aerial A similar car was used in the Lord Mayor of London s procession 1922 WELCOME TO OUR STAND International Radio Engineering and Communication Exhibition Royal Horticultural New Hall Greycoat Street Westminster London S W 1 August 19 22nd Rec Retal Comet Price Price STEREO AMPLIFIERS ARENA 210 Amplifier 34 13 0 28 0 06 ARMSTRONG 521 52 0 0 4219 6 DULCI 207 is 25 0 0 110 6 DULCI 207M E 30 0 O 2019 GOODMANS Maxamp 54 0 0 44 19 6 LEAK Stereo 30 Plus 53 0 0 43 19 6 LEAK Stereo 30 Plus in teak case 59 10 0 4119 6 LEAK Stereo 70 65 0 0 52 19 6 LEAK DID po In teak case 7110 0 56 19 6 LINEAR LT 1818 0 1519 6 METROSOUND st 20 32 0 0 25 19 6 PHILIPS RH 591 73 0 0 55 19 6 PHILIPS RH 590 49 0 0 3712 6 PHILIPS RH 580 26 0 0 19 19 6 PIONEER SA500 62 111 45 0 6 PIONEER SA700 98 0 0 7419 6 PIOML R SA900 134 2 0 EM 19 6 PIONEER Reverberatlon 45 911 35 19 6 QUAD 33 Pre amplifier 43 0 0 38 19 6 QUAD 303 Main Amplifier 55 0 0 48 19 6 ROGERS Ravensbourne 5910 0 46 19 6 ROGERS Ravensbourne cased 5g 64 0 O 49 19 6 ROGERS Ravensbrook 44 0 0 EM 19 6 ROGERS Ravensbrook cased i 49 0 0 39 19 6 SINCLAIR 2000 Gn
232. ircuit consists of a phase shift oscillator with variable frequency control approximately 5 to 10Hz the signal from which is used to drive the l d r control amplifier There are two 6V 0 04A lamps in series with the collector of this transistor one of which is used to control the 349 i t 252 o pe i Back cover Amplifier compartment Vo square beading recessed Vo back and front of cabinet Front panel secured all round with screws Batten 2x1 planed recessed 11 4 back and front of cabinet beading into chassis angle a ae 9 e aw Figs 2 above and 3 right give full details for the construction of the cabinet ld and the other as a visual tremulant indicator for the front panel The tremulant depth can be controlled so that a full or light tremulant can be obtained but the system is so arranged that the playing volume does not sharply increase when the tremulant is switched of The ids control lamp remains alight when the tremulant is switched off thus restoring the volume to a mean level The rise and fall of the tremulant is rather like that of Class A modulation in a transmitter The l d r system of control is completely free of the low frequency thump that is common with the usual combination of a phase shift oscillator and signal amplifier The tremulant variation is perfectly sinusoidal Construction Cabinet The cabinet dimensions given in F
233. isi TER 766 AL iE 5045 Un 293 9 6 EF89 65 6 GY501 16 PEN45 7 U ri Mr Sem ala se zn n San blag a eee den BR W EF9 4 6 GZ30 7 6 PEN45SDD Usz 80 VR75 30 8 8A L 3 3 EHF 6 8 NA 5i 209 10 3055 a ri DR40O 10 ECCAO E aj 3 4 wm thew VRI05 307 Re RA Ee SE ee TUS Gop RRL doe cue DROS a ECC el EFS 4 6 GZ33 195 PEN48 7 6 L5 6j VR130 308 6 SCORES eei Boss IRE GEL Bee DE AS DK96 8 ECC 6 EF 5 623 11 PENSRS10 75 5 VUSDA 10 PAR M eee tee m CIE SIL D ne ates DRE 5 6 ECCM4 8 EF9 6 HABCRO 8 6 PEN38410 Gix 5 VOL 10 6AQn 104 GP5 Si 1Y4 1g 23C a NS 8 i af pat 18 EF96 4 HBC90 5 PEN453DD UI9L 15 vp190 18 tr n6 7 3 21 nl e j 4 v2 41 M 3 Uu a 5 x 4 BARS 6 0 0F6c 5 9BWs 8 8 2 LAGT 7 6 5an 6 DL92 j ECC85 5 ae HBCal 6 11 U 0L 7 yeaa 10 BARG 6 6 6E 6 6 10 2 107 Li 8 apay 48 DLH 4 ECC8S 8 EF97 10j HFO3 6 6 PENA 8 6 C28 8 Us d ANS MA O MS ROE GA EAD PRADOS iei tah latices si betis E BFIs3 6 6 ros 5 6 Pres ato Goss 8 2309 10 SANS i ria 7 10D BE 345 8 MESS redo e oi Do MANI aug ve tare GASTA 18 grid 19 10F1 18 80A E 8j MMA 251 DLs 8 ECCOL 4 j EFIR 7 HK90n 9 6 PFBIB 17 140 DL BATO 5 BFJ5 JoF9 10j i 3001 6 6 307 8 8 DL96 ECCIS911 t EFS00 20 HL9 7 PFL20014 U
234. ith stereo cartridge 3000 with Sonotone 9TAHCD stereo cartridge SP25 Mk II SL65B Base and cover for above Base and cover for above 8 19 P amp P Decks 12 6 Base amp Cover 10 Deck Base Cover 17 6 SPECIAL OFFERS SP25 MkII with base 14 10 0 P amp P 15 SP25 Mk II with Bonotone 9TAHCD cartridge and base 415 15 0 P amp P 15 Sonotone 9TAHCD cartridge 4 2 15 0 P amp P 1 6 All Mail Orders and correspondence to Dept L5 9 Kirkman House 54a Tottenham Court Road London W I Tel 01 580 7041 2 18 19 25 amp 53 TOTTENHAM CT ROAD LONDON W 1 Telephone 01 580 2255 4532 7679 Open 9 6 pm Monday to Saturday Thursday until 7 pm 391 TECHNICAL TRAINING In ra dio television ant electronics Whether you are a newcomer to radio and elec tronics or are engaged in the industry and wish to prepare for a recognized examination ICS can further your technical knowledge and provide the specialized training so essential to success ICS have helped thousands of ambitious men to move up into higher paid jobs they can help you too Why not fillin the coupon below and find out how Many diploma and examination courses available including expert coaching for C amp G Telecommunication Techns Certs C amp G Electronic Servicing R T E B Radio T V Servicing Certificate Colour T V Servicing Radio Amateurs Examination P M G Certs in Radiotelegraphy General Certificate of
235. ith the v f o tuned to about 3 7MHz and St at 80m L3 is similarly adjusted fl TAROT een um L ed a q Reg HT Original 2000 i screened 2 D 7m pt Ua ENS PT ri 100pF LJ E e 1 yet 4 16 178 100 Ll 63V is kn bte ut E H a E 01 S REC 150 te TELF 3 2 5mH 75 pF i pF 1 Da 7 Fig 1 above shows the circuit of the modified v f o slage using readily avallable components The photograph left will assist in identifying the additional components required for 2 band operation The receiver band swltch is below the receiver tuning dial at the left of the panel The b a bandswitch S1 is below the v f o dlal centre The p a bandswitch is located in the top right hand corner of the panel continued on page 390 BSR 4 SPEED SUPERSLIM AUTO RECORD CHANGER Plays 12 10 or 7 records Auto or Manual A high quality unit backed by BSR reliability with 12 months guarantee Size 18 x 11iin Above motor board 3tin below 24in AC 200 230 with STEREO MONO XTAL 6 19 6 Posts s BSR UA70 Stereo Mono Transcription Auto Changer Calibrated Stylus Pressure 2 9 6 BSR Minichanger UA50 Stereo Mono Plays 12 10 or 7 records 7 l 9 6 Size 12 x Slin AC 200 2507 Post 5 6 o GARRARD PLAYERS with Sonotone STA Cartridges Stereo Diamond Mono Sapphire SP25 Mk If 414 19 8 AT60 Mk IX 14 19 6 Model 30
236. ithin 3 months of purchasIng Project 60 modules directly from us you are dissatisfied with them we will refund your money at once Each module is guaranteed to work perfectly and should any defect arise in normal use we will service it at once and without any cost to you whatsoever provided l e OUT that it is returned to us within 2 years of the purchase date There will be a small charge for services thereafter No DR e SE charge for postage by surface mail Air mail charged at cost zi E for which enclose cash cheque money order To SINCLAIR RADIONICS LTD 22 NEWMARKET RD CAMBRIDGE i l Please send 397 R S T VALVE MAIL ORDER CO BLACKWOOD HALL 6a WELLFIELD ROAD STREATHAM S W 16 Mon Sat 9 a m 5 30 p m Closed Sat 1 30 2 30 p m Open Daily to Callers Tel 769 0199 1649 147 7 9 12 6 6K7GT 4 6 10CI 20 25L6GT 7 150B9 11 6 DK32 7 9 ECH35 11 6 EY8G 9L PCF 6 0 PY30 9 6 UCLA 7 6 1D5 25 6K8 2 9 10C2 12 6 25Y5 6 15004 9 8 DK91 6 ECH42 198 EZao 8 PCPR9 8 8 R2 7 6 UCLS3 11 6 1H5 14 8 6K8M 11 8 0Fi 14 9 2524 6 3 801 9 8 DK92 9 ECH81 5 9 EZ40 9 PCEF84 8 R19 7 9 UF41 10 6 ILD5 13 6K8G 3 l0Es 18 2525 8 807 9 DK9 7 9 ECH8 8 6 EZ4 9 6 PCF86 9 RGo 000 80 UF89 7 6 IN5GT 5 i leK8SaT 7 lioFo 10 6 2576 8 8 813U
237. ize 21 x 11 x Gin An extremely elegant speaker system made of 42 m m chipboard covered with teak leathercioth with dark Vynair front send S A E for cloth sam ples This unique sys tem uses three ex T V speaker 6tin round for the Bass 8 x 3in for the Middle and Sin round for Treble Care fully matched and tested Will handle 10 12 watts and will match 8 ohms impedance If preferred the speakers can be wired in series parallel to match 3 chacina imbecances A real bargain at 419 6 1 P pius MATCHING TRANSFORMER for 15 ohms Seo post free BROADWAY ELECTRONICS Nr Tooting Broadway Underground Stn 92 MITCHAM ROAD TOOTING BROADWAY LONDON S W 17 01 672 3984 Closed all day Wed CONSTRUCTOR UNITS R F Generator Supplied with coils tuning cap switch and details for wiring and calibration Covers 150KH z to 30MH z 89 6 3 6 pp A F Unit Osc operates at 2 freq s for A F R F checks connects as amp for continuity checks Dual freq square wave o p for audio HiFi tests Provides modu iden for R F unit 39 6 3 6 pp S A E for Details Tweed Electronics PW NS Green Hatfield Peverel Chelmsford ssex 5 pim Rs i em AMAZING VALUE NEW BRANDED FULL SPEC DEVICES Plessey SL402A Preamp amp 2W Amp 40 GE PA234 IW Audio Amplifier 17 6 GE PA237 2W Audio Amplifier 31 6 RCA 40669 8A 400V Triac 24 RCA 40583 Trigger Diode
238. k inputs and two Volume Controls Pusb Puli 15 18 watts sectionally wound for simultaneous use of up to four pick ups 6L6 KT66 ete for 3 or 16 Q 35 9 or mikes Bass and Treble controls Push Pull 20 watt higb quality sectionally 5 5 G wound EL34 6L6 K T66 etc to3or15 Q 58 9 ANS Carr 30 or dep 13 49 SMOOTHING CHOKES Is0mA 7 100 250 E 0 10 9 80mA 10 and 9 monthly payments of 5 11 9 Total nf t CEU r q d 60 EDE Send S A E for leaflet SU en ne Oe MEO G100 100 watt peak output with Pr speaker SELENIUM RECTIFIERS F W Bridged columns aud a Bass Unit Six 19 and Two Al16 1 v D C output Mar A C input 18v 15 Speakers 994 gns la 4 3 Ya 6 11 3a 9 9 4a 12 9 Ga 15 9 GARRARD PRICES SLASHED SP25 MklI 10 15 0 p p 10 PLINTHS amp COVERS Teak finish slenderly designed ready for use For Models SP25 2025 3000 SL65B Spindle can be left in position whilst cover on Cover tinted smokey FANTASTIC VALUE 79 6 p p 7 6 GARRARD TURNTABLES MISC 2025TC Son 9tahc dia 9 10 SP25 Mk ll less cart 10 15 3000 Son 9tahc dia 9 12 SL65B Son 9tahc dia 13 19 L L Nova 565 Amp Mag amp Cer Cart Input 5 watts per Chan 15 10 0 Pp 10 coococooo0o0 AP75 less cart 15 19 SL72B less cart 24 0 J SL75B less cart 25 0 Masters MAGnetE cay p p 10 on each of the above isa E non E GARRARD SP25 AND OTHERS ON PLINTHS
239. ke the self tapping screws supplied with them The contact assemblies have two pairs of contacts one pair make as the other pair break and each pair is isolated The press to make pair are used for keying the pedal bass notes and the press to break pair are used for actuating the drum bush sound The thirteen contact assemblies are mounted on the rail Fig 10 inset and the rail is then attached to the pedal frame so that the contact sets are upper most beneath each pedal Fig 9 Note the clearance for the downward movement of the pedal To obtain the requisite spacing between the contact actuating buttons and the pads on the pedals small spacers can be fitted between the contact rail and the slots in the pedal frame materials list Planed wood for pedal frame and pedais The frame and pedals may be obtained ready made from Henrys Radio Ltd Type 13 2 Pedal contact set 13 off Leaf type 1 pair make 1 pair break Henrys Radio Ltd Aluminium U channel ling x 3x din 20Zin long Aluminium sheet 18 s w g for output socket panel Plywood woodscrews etc 371 Top rear cover Ed A Control panel supports L NR supports Small circuit board support rail REC TOC T LE CIO SS NAA AAT UN Mm un er p RN tu ANAN D Jack socket 6 M 8 pane my SA Main circuit board N A W supports iw UN UW PAN Y y Fig 8 above General view showing the d MZ construction of the wooden
240. kers Cabinets Computer panels long leads NOT printed circuits Transistors resistors new and recovered State requirc ments S A E F S for details MAIL MART 6 Eastbourne Road Pevensey Bay uSSeX rg NEW QUALITY COMPONENTS SAE list M L H Electronics 114 Kingsway Chand lers Ford Hants M M M M pt M LOW PRIGE HIGH QUALITY SPEAKER SYSTEMS All cabinets are new and carefully designed acoustically with speakers mounted on tin chipboard baffles All speakers are ex TV high quality with hi flux magnets carefully matched and tested RECEIVERS amp COMPONENTS continued CARTRIDGES Stereo Sonotone 9TA H C Diamond 47 6 Ronette S105 Medlum Output 28 6 S106 High Output 28 6 Acos GP93 1 Sapphire 31 6 GP94 1 Sapphlre 39 6 GP91 Stereo Com patible High Medium or Low Output 25 T A800 converts Phlilps AG3301 AG3306 to B S R SX1H Plug In head complete with cartridge 50 TA700 equivalent to B S R SX1M 35 Japanese equivalent to B S R TC8s 35 P amp P 1 6 Mono Acos GP67 2 will yonigee Collaro and Garrard Mono canrigges 18 6 T T C Crystal High Gain I TC8H Jap equivalent 26 P amp P 1 6 EARPIECES WITH CORD and 3 5mm plug 8 ohm magnetic 3 250 ohm 4 180 ohm with clip 6 6 Xtal P amp P 6d PIANO KEY PUSH BUTTON SWITCHES 7 button inc mains on off 6 banks of 6 P C O 8 6 P amp P 1 6 The SHELLEY S
241. ktail cabinets illuminating Cloth covered Size l62 x 141 x pictures diffused lighting etc 7 Takes any modern auto 6for l P amp P free changer P amp P 7 6 DUKE amp CO LONDON LTD 21 3 Romford Road London EI2 Tel 01 478 6001 2 3 RADIO SOCIETY GREAT BRITAIN X WIN 250 HQ 215 HAMMARLUND TRANSISTOR COMMUNICATION RECEIVER AT THE INTERNATIONAL RADIO ENGINEERING COMMUNICATIONS EXHIBITION ROYAL HORTICULTURAL NEW HALL GREYCOAT STREET WESTMINSTER LONDON S W 1 WEDNESDAY TO SATURDAY 19th to 22nd AUGUST 1970 OPEN 10 a m to 9 p m ADMISSION 4 DISPLAYS BY RADIO AND SPACE RESEARCH O ROYAL SIGNALS GOLDEN JUBILEE ROYAL AIR FORCE O ROYAL NAVY O POST AND TELECOMMUNICATIONS HOME CONSTRUCTION AND DESIGN COMPETITION AND DISPLAY O COMPLETE TRANSMITTING STATIONS WORKING THE WORLD O EDUCATION AND TRAINING INFORMATION HAND THIS ADVERTISEMENT IN AT THE DOOR FOR FREE ENTRY FOR THE ABOVE RECEIVER FG RAYER G30GR FURTHER NOTES ince the appearance of the LF bands transmitter receiver in the June July 1970 issues of Practical Wireless it is apparent that the v f o coil unit is no longer available There has also been interest in 2 band switching for the equipment This has been employed for some time with excellent results and results on 80m have been surprisingly good The VFO Fig 1 is the circuit of a v f o which can be built in the orig
242. l generator Fig 4 Use of a signal generator instead of a g d o to determine frequency of crystal If the output of the signal generator has a calibrated attenuator the goodness of the various crystals can be estimated by keeping the input voltage to the crystals constant and noting the relative deflection on the meter when the signal generator is tuned to the frequency of the crystal under test Once the fundamental frequency of a crystal has been found its performance in the overtone mode can be judged by applying signal voltages from the g d o or the signal generator at the third fifth or higher harmonics The dip shown on the g d o will be less than that obtained on the fundamental of the crystal and in the same way the output indication using a signal generator will be less as the order of the harmonic is increased l Crystals designed especially for operation on the overtone mode will naturally perform better in this test than those that are not but after testing a number of crystals the good and the bad will be obvious m Project Autumn compete ox the Practical Wireless Designers Trophy see page 390 367 organ pedal bass unit that can be used with any portable or domestic electronic organ having no bass note pedals of its own It can be tuned to pitch without having to alter the tuning of the individual notes rie the pitch of the whole Octave can be raised or lowered by approximately one ful
243. l meters Type MR 38P pedance 20 20 000cps external Illuminated scale 140 x 215 x 330 I4kin square fronts Complete with spring 150V D C 27 8 lead amp stereo jack plng ight 154 Ib 2 AO mm Weight 154 lb 220 240V A C Supplied 7 19 6 P amp P 9 6 500 0 500u A 27 8 50mA 27 6 brand new with handbook 87 10 0 Carr lmA 8 100mA 27 6 300V D C 27 6 10 1 0 1mA 27 6 150mA 27 8 500V D C 27j8 Saco Sic e 2mA 97 8 200mA 27 8 750V D C 27 8 AUTO TRANSFORMERS TRANSISTORISED L C R A C 5mA 27 8 300mA 27 8 15V A C 27 8 0 115 230V Step up or step down Fully G BRIDGE I mA 2716 500mA 27 8 50V A C 27 8 shrouded MEASURING BRIDGE 750mA 27 8 83V D C 27 8 150V A C 27 8 150 W 2 2 8 P amp P 3 6 A new portable l amp 27 8 10V D C 27 8 300V A C 27 8 300 W 23 5 0 P amp P 4 6 prides onere FE 2amp 27 8 15V D C 27 8 500V A C 27 8 500 W 4 4 10 0 P amp P 6 6 cellent ED Samp 27 68 20V D C 27 8 SmeterimA 82 1 000 W 6 10 0 P amp P 7 6 RN 20mA 27 86 100V D C 27 6 VU meter 42 UA LA K AEN EA x P ES 103411 do EY FULL RANGE OF OTHER SIZES IN STOCK SEND 8 A E FOR LEAFLET x MU DLE SML i mara IU TI L I u 11 o SX ERE Variable Voltage TRANSFORMERS ges 25 5 C 10pF ei 1110mFd 6 Brand new guaranteed and carriage paid Ranges 2 T
244. l note It features a drum brush accompaniment that sounds each time a pedal is pressed regardless of whether the pedal is pressed and released quickly for a bass note of short duration or the pedal held down ik is a self contained 13 note single octave ns a x arn an crue o a prm Preta a Na Hd to sustain the bass note The drum brush sound 3 w a MS m Tuae m begins with an attack and decays of its own accord The output signal level is sufficient for any external amplifier requiring not more than 1 volt r m s signal input The pitch available is 16ft or 8ft or 16 and 8ft combined The 16ft octave is C to C 32 to 65Hz approx and the 8ft C to C 65 to 130Hz approx These two pitches are combined in equal proportions of amplitude when the 16 8ft pitch is used The voicing is flute or clarinet which is fairly conven tional for domestic electronic organs e Di gt ar Si Circuit The block diagram Fig l shows the general circuit arrangement which employs a total of nine OC71 transistors The consumption is quite low so that operation from a PP9 9V battery is econo mical There is little point therefore in making the i oe Tone generator een 16 ft Divider Tr3 Tr4 Mutti vibrator Tri TRA Buffer amplifier Tr9 Output PS O Drum brush Voicing Noise generator Attack decay network All transistors and filter control e
245. ll further ranges can be added TRANSISTOR TESTER Many readers will occasionally wish to test transistors but do not feel that the construction of a separate piece of equipment is justified For these people a separate and simple circuit can be kept for the odd occasions on which it is needed the cost should be no more than a few shillings as it uses only a three pole four way switch and a 100kQ resistor Although this tester only measures the transistor using the internal battery almost universally 1 5V in the cheaper range on multimeters it will give an T is one piece of equipment that all of us 100k A Collector Q ys M gt Meter on ohms range Switch positions A PNP gain B PNP leakage C NPN leakage D NPN gain k E dits 3 C E ES J Fig 1 The circuitry necessary for converting a multimeter to a tran sistor tester indication of leakage and gain In position A the meter s battery negative is applied to the collector and the positive to the emitter the resistor connected between the collector and the base applying a bias of about 10uA A good device should show quite a deflection on the scale In position B the bias is removed and the meter indicates the leakage Positions C and D do the same for NPN transistors Note that there is not a mistake in the circuit the positive connection to the meter is in fact connected to the battery negative LOW VOLTAGE RAN
246. ll output and all lower outputs Whether you use the Z 30 or Z 50 power amplifiers in your Project 60 system will depend on personal preference but they are both the same physical size and may be used with other units in the Project 60 range equally well The Z 30 is unique in that it may be used with any power source between 8 and 35 volts without need for adjustment and may thus be driven from a car battery for example For operating from mains for the Z 30 use PZ 5 power supply unit for most domestic requirements or PZ 6 if you have very low efficiency loudspeakers For Z 50 use the PZ 5 PZ 6 or the PZ 8 described below SPECIFICATIONS Power Outputs Z 30 15 watts R M S into 8 ohms using 35V 20 watts R M S into 3 ohms using 30 volts Z 50 40 watts R M S into 3 ohms 30 watts R M S into 8 ohms both continuous using 50V Frequency response 30 to 300 000 Hz 1 dB Distortion 0 02 77 into 8 ohms Signal to noise ratio better than 70 dB unweighted Input sensitivity 250mV into 100 Kohms For speakers from 3 to 15 ohms impedance Size 31 x 21 x 1 40 WATT R M S POWER AMPLIFIER i 80 WATT PEAK APPLICATIONS Hi fl amplifler car radio amplifier record player amplifler fed directly from pick up Intercom electronic music and instruments P A laboratory work etc Full detai s for these and many other applications are glven In the manual supplied with the Z 30 Power versus distortion curve of Sinclair Z 30 and Z 50
247. ltenham 21491 Ext 2270 particulars m a em im EDUCATIONAL continued m TRAIN FOR SUCCESS WITH ICS Study at home for a progressive post in Radio TV and Electronics Expert tuition for City amp Guilds Telecoms Techn s Cert and Radio Amateurs R T E B etc Many non exam courses incl Colour TV Servicing Numerical control amp Computers Also self build kit courses valve and transistor Write for FREE prospectus and find out how ICS can help you in your career ICS DEPT 541 INTERTEXT HOUSE STEWARTS ROAD LONDON SW8 RADIO OFFICER training courses Write Principal Newport and Monmouthshire College of Technology Newport Mon HI FI EQUIPMENT eo SHURE GOLDRING Cartridges Post Free G800 M44 5 7 7 17 6 M3D 5 5 0 M44E 8 19 6 MSSE 9 19 6 M75E 2 16 10 0 GARRARD SP25 2 10 17 6 AP 75 16 17 6 p amp p 7 6 Ultimate Electronics 38 Achilles Road London N W 6 Mail Order Only 403 WANTED ere CASH PAID for New Valves Payment by return WILLOW VALE ELECTRONICS 4 The Broadway Hanwell London W 7 01 567 5400 2971 ae temo WE BUY New Valves and Transistors State price A D A MANUFACTURING CO 116 Alfreton Road Nottingham n l WANTED NEW VALVES ONLY Must be new and boxed Payment by return WILLIAM CARVIS LTD 103 North Street Leeds 7 WANTED NEW VALVES televisions r
248. m needle to pivot length 223mm ofiset angle 24 overhang 10mm Requires single 7 16in dia mounting hole LASKY S PRICE 9 19 6 ros 3 Stereo Magnetic Cartridge Frequency response 20 20 000Hz Output 5mV Stylus Diamond LP 90 ms Post Tracking force 2 ams 0 5 gm Free Replacement stylus type JS P1 41 Post Free t free AUDIO DEVELOPMENT AD 96K Tracking force 2 gns The 1970 edition of Lasky s Audio Tronics cat a d Communications Ham Covers every aspect of Hi Fi including Laskys budget Ste SEND TODAY Send your name address and 2 for post and inclusion of Stereo Magnetic Cartridge Frequency response 4 5 18 Replacement styius type Y 960S 51 6 pos alogue is available FREE on request Packed with 1000 s of items for the Radio an reo Systems and Package Deals Tape recording and Audio accessories P your name on our regular mailing list 20 20 000Hz Output 5mV Stylus Diamond LP Audio Tronics 7O d Hi Fi enthusiast Elec tronics Hobbyist Servicemen an lus Lasky s amazing money saving vouchers worth over 25 This month s voucher worth 30 a Tel 01 723 9789 329 MOLY A FAST EASY WAY TO LEARN BASIC RADIO AND ELECTRONICS Build as you learn with the exciting new TECHNATRON Outfit No mathematics No soldering hut you learn the practical way Now you can learn basic Radio and Electronics at home the fast modern way You
249. mbols Therefore although the same signal is applied to each from the collector of Tr2 there is 180 phase difference between the signals passed on to the output pair since Tr3 may be regarded as an emitter follower while Tr5 is common emitter and therefore signal inverting Tr4 and Tr6 then act as class B push pull output transistors However due to the presence of the diodes and small resistance between the bases of Tr3 and Tr5 To radio vol controi Fig 2 Circuit of an audio stage suitable for a pocket radio there is a small standing current in the output pair even in the no signal or quiescent condition to minimise the crossover distortion sometimes found in class B systems In practice the current drain of the circuit rises from an average of 3 5mA in the quiescent condition to 60 mA on full load The advantage of class B operation with battery drain highly dependent on output is evident Sensitivity is high with a power output of 50mW average pocket radio listening level available on an input signal of only 15 mV but Fig 3 indicates the use of an external preampli fier should one be desired for special low signal applications such as operation from a tape head Otherwise the circuit shown in Fig 2 should be fully satisfactory 9V 250 uF 150 5100 Hen 33kN2 uF Fig 3 Alternative circuit using a discrete pre amplifier It is hoped to introduce shortly the Motorola MFC4010P as the ne
250. more powerful amplifiers All you need to assemble your Project 60 system is a screw driver and soldering iron No technical skill or knowledge whatsoever is required and in the unlikely event of you hitting a problem our customer service and advice depart ment will put the matter right promptly and willingly Project 60 modules have been carefully designed to fit into virtually all modern plinth or cabinets and only holes need be drilled into the wood of the plinth to mount the control unit and the A F U Any slight slip here will be covered by the aluminium front panels of these two units The Project 60 manual gives all the building and operating instructions you can possibly want clearly and concisely Perhaps the greatest beauty of the system Is that it is not only flexible now but will remain so in the future as the latest additions to the range show A stereo F M tuner is next to come These and all other modules we introduce will be compatible with those already available and may be added to your system at any time And because Sinclair are the largest producers of constructor modules in Europe Project 60 prices are remarkably low Telephone 0223 52731 20 WATT R M S POWER AMPLIFIER B 40 WATTS PEAK The Z 30 together with the higher powered Z 50 are both of advanced design using silicon epitaxial planar transistors to achieve unsurpassed standards of performance Total harmonic distortion is an incredibly low 0 02 at fu
251. n 3 inch MOVING COIL METERS BRITISH MADE Various calibrations movements 500 Microamp 3 1 Milliamp 50 0 50 Microamr etc 8 A E for list MAINS ELECTRIC MOTORS 1207 or 240v AC Size 24 x 24 x Iljin leche 1 200 r p m off load Heavy dety 4 pole 50mA Spindie 3 x 3 20 BARGAIN 7 16 EACH PRICE Post 2 8 8 for 50 6 for 90 CALLERS WELCOME Tel 01 684 1665 387 E MES e pe oe s eae puces qu e iat m uc c0 G In four stable ranges wave right through the shipping an n rnational amateur bands U the short wave and inte cored LF CODAR COL air space in transformers pro high selectivity volt AC mains th our aerial a da The inet measures o x TH and the i ack and W ite with chrome r feeding tape NAVE R F pRE SELECTOR MODEL p R 30 4 5 30Mc S 1 y Separate electrical provides up to 20dB gain plus substantial Can 9 i Output image rejection impf ved signal noise ratio piete with valve one etres d selectivity ower Fe uirements 480 250 nd 4 P instruction man al Price 6 3 volts mp LT Size 55 Cart 3J Ext coils 6 3 tete with cables on w mot pearer tValv a Ecce an Si X T CODAR KIT volts 49m H T 9 60 179 84 Say 47 Ready built comp ete d instructions 6 10 0 Carr 5j 40 0 Cart 5l s an 9 transistors 3 5 AMCIS 42 vols only X ideal portable mo ie or home receiver Eficient printed circuits FB4 280 Size 1 ONLY
252. n Chrome and Black Leather Ultra sensitive 15 transistor circuit Earpiece and Socket Leather carrying and shoulder straps Batteries incl STANDARD EVER READY TYPE RETAIL TRADERS SUPPLIED Enquiries to wholesale dept STOCKTON PARTNERS DEPT PW BRIGHOWGATE GRIMSBY LINCS Tel 0472 64196 58815 Imports Wholesale Electronic Equipment Distributors NEW TESTED amp GUARANTEED PAKS made ee Sos PEERS CUTS B2 Photo Cells Sun Batteries 3 to 5 volt 4 5 to 2 ma L 10 H8 4 BY127 Silicon Recs 1000 P T V 1 amp 10 Plastic Replaces the BY100 B73 4 1N4007 Sil Rec Diodes 1 000 P I V 10 lamp Plastic B81 Reed Switches mixed types large If i 0 and small 9 0 E isa ei ee ee B89 2 SSP Light Sensitive Cells Light Res 10 400Q Dark IM Q B91 8 NKT163 164 PNP Germ TO 5 0 equivalent to OC44 QC45 B92 4 NPN Sil Trans 406 B8X20 2N2369 10 500 MHz 3650mW as E a B93 5 GETII3 Trans equiv to ACY17 to 10 ACY2 PNP Germ B96 5 2N3136 PNP Sil Trans TO 19 HFE 10 j 100 300 I C 600mA 200MHz B98 XB12 and XB102 equiv to ACI26 E AC156 OC81 2 0C71 2 NK271 etc eee e mem H4 250 Mixed Resistors Post and packing 2 10 J Sa Sh H7 Wirewound Resistors Mixed Values j 40 Postage 1 6 10 H9 2 OCP71 Light Sensitive Photo Transis 10 tore 8 FOR 20 P O RELAYS Various Contacts and Coil Resistances Post amp Packaging 5 ALL OU
253. n DIN plugs 8 3 pin DIN plugs 3 5 pin DIN plugs 8 5 2 pin 3 pin DIN sockets 1 6 wander Plugs 6d sockets 8d Banana plugs 1 1 socketa 1 3 5mm J Plugs 1 6 amp 2 6 Standard J Plugs with solder terminals 2 Chrome 3 Bide Entry J Plugs black and chrome 4 9 Insulated j sockets o cct 3 8 c ect 3 6 ELECTROLYTIC CAPACITORS 4uF 160v 8d 8uF 500v 3 8uF 12v 10d 8uF 8uF 450v 4 8 10uF 150v 9d 12uF 25v 9d 16uF 450v 2 9d 16uF 16uF 450v 4 8 30uF 10v 8d 50uF 10v d 100uF 9v 9d 1000F 12v 9d 150uF 12v 9d 320uF 9v 1 15000F 30v 3 8 2 5uF 10v 6d louF 16v 1 6 5000uF 25v 10 10 000nF 95v 15 20 0000F 30v 91 MICROPHONES Acos Mic 45 22 6 Acos Mic 60 19 11 Planet CM70 30 Hand Mike 15 Shure 201 5 Shure 444 10 10 0 VALVES PY81 7 2 PCL82 7 9 EF183 9 EF184 9 GEORGE FRANCIS Dept PW 83 Balderton Gate Newark Notts Telephone Newark 4733 y B83 Trans Makers 200 Sil and Germ ONLY 10 NEW UNMARKED UNTESTED PAKS H10 25 Hed volta 11 watt Zeners Top Hat 10 j B80 Dual Trans Matched O P palra NPN 10 8H in TO 5 can CS e e qdo H11 30 Mat series Alloy PNP Transistors 10 rejects NPN PNP 10 B84 100 Rilicon Diodes DO 7 glass equiv to 10 0A200 0A202 H15 30 ps elias Rectifiers 750 mA 10 j B86 50 Rai sub min IN914 and IN916 10 J H16 EXSEUmnCRHMEPIK o EIDUIRMTIREROS DUE RENI den 10
254. n GUARANTEED in Every Pak or money back Pak No NEW BI PAK UNTESTED SEMICONDUCTORS i c AMPLIFIER Ident iE Sal ion and pin O a SE f the following 8L402 NEW Lad PRICED MESSED E SIL REJECTS TESTED Ul 120 Glass Sub min General Purpose Germanium Diodes 10 IC10 and IC403 Each 3A 0A PIV 750m US 60 Mixed Germanium Transistors AE RF 10 circuit incorporates a pre ro 5 TO 66 TO 48 TO 48 50 I Arjo a 916 U3 75 Germanium Gold Bonded Diodes sim OAS OA47 10 amp and class A B case case case case 100 1 3 3 3 4 6 15 0G ium Tranai ACIOS Power amp stage capable PIV each each each each PIV each 200 1 9 4 4 9 20 U4 ermanium Transistors like OC81 ACI28 10 or delivering up to 3 watts 50 4 6 5j 9 6 10 6 25 20 300 2 3 4 6 6 6 22j U5 60 200mA Sub min Sil Diodes 10 RMS Fully tested and 100 5 6 6 10 6 12 6 50 23 400 2 6 5 6 7 6 25 U6 30 Silicon Planar Transistors NPN sim BSY95A 2N708 _10 e eos Riga cn 200 7 7 6 16 15 100 28j 500 3 6 8 6 30 07 16 Bilicon Rectifiers Top Hat 750mA upto L000V 10 qoe end date CODEI 400 8 6 9 6 13 6 18 6 200 32 600 3 3 6 9 9 37 aa L TIS DINA naramoan details and data CODED 600 10 6 11 6 15 6 25 400 35 800 3 6 7 6 I Ij 40 Us 50 Sil Planar Diodes 250mA OA 200 202 10 BP1010 O
255. n be used and with this the PASO power output module will deliver 25 watts r m s If the full 50 watts should be required at a later date it will only be necessary to fit the additional loudspeaker With a pair of type 12P Goodmans 12 inch 8 ohm loudspeakers used in parallel the power module load becomes 4 ohms across which the module will deliver 50 watts r m s power These Goodmans loudspeakers are a new range recently released by the manufacturers and have been specially designed for musical instrument amplifiers Note that the use of loudspeakers other than those specified would in all probability spoil the performance of the amplifier Under no circum stances must the power module output load be less than 3 ohms Qvi facilities smi high power guitar amplifiers Amplifier Facilities One of the special features of this amplifier is the tone tremulant system which produces a tremulant effect similar to that obtained from the rotating loudspeaker systems used in electronic organs Leslie speakers The tone tremulant can be varied to any degree but when turned off leaves normal amplitude tremulant as found on most guitar amplifiers The 348 F C JUDD sa a E s is ay E 5 Y a gp rn 1 Ee e st Ea E EI E Guest m EE Se ww ms E pra lim va a 4a 7 p 5 s er ime m e pe Er LIFIER amplifier can of course be used without either of the tremulants
256. nce thrilled of world wide news sport etc Uses PP3 battery Traneistorised no valves Size only 3 x 4j x 13 45 3 6 p amp p for all parts including cabinet screws instructions etc Parts available aepar ately Money back guarantee CONCORD ELECTRONICS LTD PW11 8 Westbourne Grove London W 2 nr Bayswater Tube Callera 9 6 inc Bat e mw ww NS A E NE CC M r 7 PRICES amp LARGEST STOCKS A1617 3 40 AMOO6 10 BD119 15 BSY95 3 2 NKT163 6 NKT351 10 OC70 2 6 40320 7 3 2N2148 12 6 3N140 15 3 AAY30 17 ASY26 45 BD121 18 BSY95A 2 11 NKT164 6 NKT352 17 6 OC71 3 40323 6 6 2N2160 14 9 3N141 14 6 AAZI3 32 ASY27 6 HBD123 21 6 BSw41 8 6 NKT165 6 NKT361 20 OC72 4 6 40324 9 3 2N2218 6 5 3N142 10 9 AC107 7 7 ASY 8 4 5 BD124 12 2 BSW70 5 6 NKT201 6 NKT362 20 OC74 8 40326 7 3 2N2368 3 4 3N143 13 3 A C126 5 ASY29 6 7 BDY20 20 8 BY127 4j NKT202 6 NKT401 14 6 OC75 4 6 40329 4 9 2N2369 3 4 3N152 17 3 AC127 4j ASZ 76 BF115 5 C106F 9 NKT204 6 NKT402 15 0C76 2 6 40344 5 3 2N2369A 3 11 AA119 2 AC127Z 9 6 AUY10 30 BF152 13 6 C111 18 NKT205 6 NKT403 149 OCH 5 6 40347 7 6 2N2614 4j AAZI3 2 6 A C128 4j B1181 10 BF154 9 CE 12 NKT206 6 NKT404 1177 OC81 4 6 40348 10 3 2N2646 10 BA110 6 AC176 5 B2M 12 6 BF159 15 CR1 051 8 7 NKT208 6 7 NKT405 11 OCS8ID 3 40360 8 6 2N2712 6 BAl111 6 AC187 12 B3M 15 BF163 9 C
257. ne pre amplifier Trl and Tr2 has a microphone transformer included in the input circuit which should be used if the microphone is low impedance 25 to 30 ohm type Microphones of 200 ohms impedance can be used without a trans former as also can other microphones with a high impedance output i e with a built in low to high impedance transformer continued on page 354 components list A mmus ms Resistors R1 47kQ R13 8 2kQ R25 150kQ R37 47kQ R2 1 5kQ R14 22kQ R26 1 8kQ R38 47kQ R3 120kQ R15 56kQ R27 4700 R39 120kQ R4 12kQ R16 10kQ R28 1 2k0 R40 4 7kQ R5 5600 R17 18kQ R29 1kQ R41 1000 R6 12k4 R18 2702 R30 4 7kQ R4 12kQ R7 2 2kQ R19 47kQ R34 22kO R43 5600 R8 1kQ R 0 47kQ R32 100kQ R44 1 5kQ R9 150kQ R21 4700 R33 18kQ R45 22kQ R10 8 2kQ R22 47kQ R34 10k R46 5600 R11 1 5kQ R23 120kQ R35 22kQ R12 68kQ R24 12kQ R36 47kQ All resistors 1W 10 miniature VR1 Microphone Volume 100kQ log VR Tremulant Speed 50k 2 linear VR3 Tremulant Depth 10kQ linear VR4 Guitar 1 Volume 100kQ log VR5 Guitar 2 Volume 100kQ log VR6 Treble Control 50kQ linear VR7 Tremulant Tone 100kQ log VR3 Master Volume 100kQ log VR9 Wah wah Contro 100 kQ linear Capacitors C1 0 02uF polyester C11 0 1uF polyester C21 2 5uF 25VW C2 100uF 12VW C12 100uF 12VW C22 0 05uF polyester C3 200pF C13 O LF polyester C23 100uF 12VW C4 100uF 12V W C14 200pF C24 200pF C5 2 5uF 25VW C15 100uF 12VW C25 100uF 12VW C6 500uF 25
258. nnel nett Complete unregulated power supply kit 87 6 nett ZENER DIODES 5 full range E24 values 400mW 2 7V to 30V 4 6 each 1W 6 8V to 82V 9 each 1 5W 47V to 75V 12 each Clip to increase 1 5W rating to 3 watts type 266F 8d CARBON TRACK POTENTIOMETERS long spindles Double wiper ensures minimum noise level MO metal oxide Electrosil TR5 ultra low noise rating NOT mized values Ignore fractions of 1d on total WW wire wound Plessey resistor order Valnes E12 denotes series 10 19 15 18 22 27 33 39 47 56 68 89 and their decades E24 denotes series as E12 plus 11 13 16 20 24 30 36 43 51 62 75 91 and their decades MULLARD polyester C280 series 250V 20 0 01 0 022 0 033 0 047 8d ea 0 068 0 1 Od ea 0 15 11d 0 22 1 10 0 38 1 5 0 47 1 8 0 68 2 3 1uF 2 9 1 5uF 4 2 2 91 F 4 9 INTEGRATED CIRCUIT AMPLIFIERS SINCLAIR IC10 complete with instruction book giving amplifier circuit details and range of applications 59 6 nett PLESSEY SLA08A Now only 42 6 nett 3W into 7 542 for MULLARD SUB MIN ELECTROLY TIC C428 range axial lead 1 8 each Values uF V 0 64 64 1 40 1 6 25 25 16 2 5 64 4 10 4 40 5 64 6 4 8 4 6 4 25 8 4 8 40 10 2 5 10 16 10 64 12 5 25 16 40 20 16 20 64 25 6 4 25 25 32 4 32 10 i 32 40 32 64 40 16 40 2 5 50 8 4 50 25 50 40 64 4 1 9 18V supply Application da
259. o telescopic aerial ED f Tri l Jo lt a NE ve Battery Ew r7 MESAS ES 1 Fig 2 Suggested component layout omponents list VC1 25pF see text C1 100pF D1 OA70 L1 see text M1 0 1mA moving coil meter Tri OC71 VR1 10kQ pot with switch R1 680 R2 6800 B1 1 5V battery Five way tag strip case telescopic aerial 16 s w g enamelled copper wire CALIBRATING AND TESTING To test the unit it should be held with its aerial about 18in from the transmitter aerial The field strength meter tuning control should then be turned slowly until a reading appears on the meter It is advisable to get the field strength meter calibrated approximately and the easiest way of doing this is to use a signal generator the earth of which should be connected to the positive rail The output lead from continued on page 365 363 AERIAL DIDNAL BOOSTER P HAND Te need for this amplifier became apparent because of the reduction in signal strength when operating a portable radio in a car Listening was made practically impossible particu larly to B B C Radio 2 Although the set has a socket for a car aerial which is connected to a loop winding on the ferrite rod and a proper wing mounted car aerial was used A large amount of interference was picked up even though the sparking plug leads were suppressed the car generator out
260. oN 00 O0 uUMWMN M 8 4 15 9 Ti Discount Price 63 7 32 39 49 52 65 30 37 5 7 13 O OF Mail 10 10 0 i0 10 i0 10 15 17 I5 0 0 15 17 10 10 10 10 10 90000000 09000 O O oo 0000000 O o oooooooooooo 0000900000 0040000040 9909000 0000040040000 0 0 Order Department ADC 10E Mk Il GOLDRING CS9IE NEAT V7OEZ PICKERING VII5 AC2 SHURE M3IE SHURE N3IE SHURE M32E SHURE N32E SHURE M44 7 SHURE N44 7 SHURE M44E SHURE M75 Ej ADC 660 GOLDRING G850 GOLDRING G800 GOLDRING G800E GOLDRING G800 S E GOLDRING CS90 NEAT V70 PICKERING VI5 AME2 PICKERING VIS AM2 PICKERING VI5 AC2 SHURE M3D M SHURE N3D SHURE N44E SHURE MSSE SHURE NSSE SHURE M75 6 SHURE N75 6 SHURE N75 E SHURE VISI SHURE VNISE ovo is Ww 4 sl w oj ce R a4 NM o d de 9 wv v amp EE Ww J a P Secs ue x a a s e e e e e q a AP SMITHS FOR SERVICE amp TOP DISCOUNT Rec Retail Price l 6 46 4 6 10 13 O0 18 17 26 O0 5 4 7 16 5 4 7 IS 5 13 10 8 7 5 1 12 1 9 12 8 10 6 14 10 16 11 16 8 24 tt 40 16 AWAWOBRAROAMOO WUNWOMHROWD OO OOND WUN DAWNWWHOWHROUD_ OD Discount Price 13 36 5 8 i5 19 4 7 6
261. oke Size 2 in x 2in x lin 14 6 postage 919 Veto eae T tiere ELECTRONICS CROYDON LTD Dept PW 266 London Rd Croydon CRO 2TH Also 102 3 Tamworth Road Croydon 331 Complete 24 FIELD EFFECT TRANS AMPLIFIER Yee Discount FET MkI 145 plus 7 6 p amp p S pecification Output per channel 10 watts r m s Frequency bandwidth 20 Hz to 20 kHz 1db at 1 watt Total distortion at 1 kHz at 9 watts 0 5 Input sensitivities CER P U 100mV into 3 meg ohms Tuner 100mV into 100K ohms Tape 100mV into 100K ohms Overload Factor Better than 26db The 29 10 0 Stereo system The Duetto is a good quality stereo amplifier attractively styled and finished It gives superb reproduction previously associated with amplifiers costing far more SPECIFICATION R M S power output 3 watts per channel into 10 ohms speakers INPUT SENSITIVITY Suitable for medium or high output crystal cart ridges and tuners Cross talk better than 30dB at 1Kc s RADIO amp TV COMPONENTS 2ic High Street Acton London W 3 Aiso at 323 Edgware Road London W 2 ALL ORDERS BY POST TO OUR ACTON BRANCH Terms C W O Acton All enquiries S A E This superb stereo system is a real price break through It comprises the VISCOUNT F E T Mk i amplifier on which full details are given below the famous Garrard SP 25 Mk II including teak veneer base and transparent cover with diamond cartri
262. ollector load and the output is taken from C3 The total current drain from the nine volt battery is under 1mA All the components except the switch are mounted on a piece of Veroboard 215 x 1 ins Only one break in the Veroboard is required the hole for mounting is also drilled at this point Component layout is shown in Fig 2 Two methods of housing the amplifier are possible The authors method was to mount the amplifier inside the case of the radio with which it is going to be used A small bracket was made on which a double pole switch is mounted together with the amplifier A thin piece of insulating material is put behind the Veroboard to insulate it from the Alternative method of using the signal booster is to bulld It into a tin as shown above bracket This method of housing can be used when there is sufficient space The second method should it prove impossible to find sufficient space is to build the amplifier into a small case as shown in the photograph with its own battery A short length of co axial cable is used to connect the amplifier to the radio via the aerial socket 27MHz FIELD STRENGTH METER continued from page 363 the generator should then be held near the field strength meter aerial The signal generator should then be set to 27M Hz and the field strength meter control VC1 tuned slowly for the maximum meter reading The dial reading on the field strength meter should then be noted and ma
263. olts For Crystal or Ceramic PUs High Impedance mikes For Musical Instrumenta etc Std AC mains For 3 amp 15 ohrn epkra SAE for leaflet COMPLETE KIT Full instructions 91 Gns and point to point wiring diagrams Carr 11 6 Twin handled 2 metal cover 35 PRICE FACTORY BUILT 13i gns or Deposit 8 and 9 monthly payments of 80 5 Total 16 13 9 RSC ALIT TRANSISTORISED VERSION of above complete kit 9 Gns Assembled 13 Gns 30 WATT HI FI AMPLIFIE FOR GUITAR VOCAL OR INSTRUMENTAL GROUP A 4 input 2 volume control Hi Fi unit wilh Separate Bass and Treble controla B V A valves Peak output rating Strong Rexine covered cabinet with handles Attractive black gold facia panel Neou indicator For 200 950v A C mains For 3 or 15 ohm 19 Gns Carr r speakers Send B E for leatlet 19jp eS Dep 74 amp 9 mthly paymts ot 2 gns Total 22 12 0 FANE ULTRA HIGH POWER LOUDSPEAKERS FANE All power ratings are R M 8 continuous 2 years guarantee Hish flux ceramic magnets Heavy cast chassin LOUDSPEAKERS x POP 100 POP 60 POP 50 POP 30C E 18 100 Watt 15 60 Watt 12 50 Watt I2 25 Watt Dual cone 152 4 500 gauss 4 000 gauss 14 000 gauss Uamitable Bess 8 15 0 ajisa Ocns 150485 Guitar or Elect 21 GNB 12 D Carr iree Organ Carr free Carr free Gen Purpose Pr 5 19 Carr Suit Bass or Rhythm Guitar or Elec Organ req for Baas Gtr free A eee ee
264. on a tripod may be used to project the sun on to a card and spots can then be observed upon the card indicating sunspot activity Never look at the sun through a telescope even though it may be supplied with a special filter to fit over the lens These filters can fracture under concentrated heat Even when the sun is setting no attempt must be made to view the sun directly Bl PROJECT AUTUMN Are you entering for the competition Are you stuck for ideas What about designing A cassette tape recorder A general purpose oscilloscope A car radio tape player An intercom system for the home A wavemeter to comply with the amateur transmitting service regulations See page 390 for details of PROJECT AUTUMN VISIT US RSGB SHOW AUG 19 22 315 TAKE 20 JULIAN ANDERSON A series of simple transistor projects each using less than twenty components and costing less than twenty shillings to build own if we take the hobby at all seriously and that is a multimeter These cost anything from under 2 to over 30 though the majority fall in the 3 to 7 range Although all of them will measure voltage current and resistance the ranges are often inadequate especially on the cheaper types For a few bob several additional features can be added to the cheaper and simpler testmeters We shall describe four circuits but with a little imagination and application of Ohms law it will be seen that sti
265. onstructional details of the wooden pedal frame of the unit lif D jw ik M cal ju dou key ii i n T T h na 8 hene E MU PL RC ri iL All 5 dia dowel pittars a in Y deep holes Allow for a length of Lr above surface Glue into holes Upper pedal du Ig he Fig 3 om of the pedais on the LA POMA with n heading EM of ife completed unit 17 Ew dem lt lt a gt gt gt e e E Iz a eme 7 z Contact pad r thick hardboard glued on all pedals Side view t Leni a RE r e cd xh t ae es Leave as white wood or paint white Is E ap E Soft leather binder all pedals Underside view 8 white key pedals Secure with roundhead screws Material Bennet bronze Holes e strip 5 thick T dia Pedal spring one on each pedal underside Fig 5 Details of the phosphor bronze springs and their fitment to the pedals 370 Pedal movement Contact pad i Rear pedal hs d support rait Fig 6 Fitting of the springs to the pedal frame unit cie Li ag lea Control panel Top aluminium hardboard XY Bas iu SSS Wh ron x T E anel 7 KCCI ISI Lower cross members TELEZETT Base cover mn Frame members all 1 x 1 batten e lt 2 NE L LE e ee ee eee ea ee Nee Rear panet hardboard
266. or of Trl and go via capacitor C3 to transistor Tr2 operating as an emitter follower stage signals pass via C and the screened cable to the receiver aerial socket In order that the preselector can be switched off when the user wishes to listen on other bands say 1 8 3 5 or 70MHz a combined In Out By pass switch Sla b is provided This disconnects the battery and at the same time allows the aerial to be fed through to the receiver The switch can also be used for checking the effectiveness of the unit by comparing receiver S meter readings with the device alternatively In and Out An increase of at least 24 S points has been noted on the meter of an Eddystone 888A on the 21MHz band with the signal peaked correctly by means of VCI This means that the unit is of particular value when copying weak c w or a m signals 6v Sla b ganged Sib Out In To e C5 receiver aerial 100pF socket SK2 R5 33k ve Fig 1 Circuit of preselector Note the capacitor between Tr1 and Tr2 is C3 100pF 359 CONSTRUCTION A 6 in square of 18 s w g aluminium sheet bent centrally into an L shape is used as a combined panel and chassis As may be seen from the wiring and layout plan of Fig 2 the battery can also be accommodated on the chassis Two simple Lektro kit tag strips act as small component anchors the transistors are soldered in last of all The coil is fixed to the base plate in the
267. orates a single power stabiliser which would be fitted in the d c output line for single output inverters or in the input to the inverter where multiple outputs are specified Finished dimensions for the power ratings quoted are 4in X 3 3in X2in and the weight is 24ozs Fixing is by 4BA tapped bushes in the base of the unit Full details of the new range and the new service may be ob tained from Gardners Trans formers Limited Christchurch Hampshire BH23 3PN building computers E Bi Pak I C s A complete range of Digital T T L Integrated Circuits is to be launched by Bi Pak Semi conductors to cover the popular 74N series of logic units These will be available in the dual in line plastic package at approxi mately half the normal distribu tion price The range includes gates flip flops and complex units such as divide by 16 4 bit binary counters shift registers and deci mal decoders plus nixie tube drivers It is hoped that with the low price and guaranteed supply which Bi Pak have arranged with the manufacturers the teaching and experimental use of Integrated Circuits which up to now have been almost non existent for most amateur concerns will at last become a reality Bi Pak hope to publish in the near future enough circuitry for calculators etc using the Integrated Circuits mentioned Bi Pak say their aim is to further reduce the cost for amateur electronics an
268. os ret ve SUV Ty E Fa fi ires p cU 2 E irae ner piste E theworld s most advanced The Sinclair 1C 10 is the world s first monolithic integrated circuit high fidelity power amplifier and pre amplifier The circuit itself a chip of silicon only a twentieth of an inch square by a hundredth of an inch thick has an output of 5 watts R M S 10 watts peak It con tains 13 transistors including two power types 2 d odes 1 Zener diode and 18 resistors formed simultaneously in the silicon by a series of diffusions The chip is encapsulated in a solid plastic package which holds the metal heat sink and connecting pins This exciting device is not only more rugged and reliable than any previous ampli fier it also has considerable performance advantages The most important are complete freedom from thermal runaway due to the close thermal coupling between the output transistors and the bias diodes and very low level of distortion The IC 10 is primarily intended as a full performance high fidelity power and pre amplifier for which application it only requires the addition of such components as tone and volume controls and a battery or mains power supply However it is so designed that it may be used simply in many other applications including car radios electronic organs servo amplifiers it is d c coupled throughout etc The photo graphic masks required as part of the process of producing monolithic Cs are expensive but once
269. p P 2 6 TELESCOPIC AERIALS WITH SWIVEL JOINT Can be angled and rotated in any direction 12 section Heavy Chrome Extends from 7in to approx o0in Maximum diameter jin 10 each P amp P 1 6 6 section Lacquered Brass Extends from 6in to 22tin approx Maximum diameter iin 5 each P amp P 1 BRAND NEW MULTI RATIO MAINS TRANSFOR MERS Giving 13 alternatives Primary 0 210 240v Secondary combinations 0 5 10 15 20 25 30 35 40 60v half wave at 1 amp or 10 0 10 20 0 20 30 0 30v at 2 amps full wave Size 3in long X 3 in wide x 3in deep Price 35 P amp P 6 MAINS TRANSFORMER For transistor power supplies Pri 200 240v Sec 9 0 9 at 500mA 14 P amp P 2 6 Pri 200 240v Sec 12 0 12 at 1 amp 17 6 P amp P 2 6 Pri 200 240v Bec 10 0 10 at 2 amp 27 8 P amp P 3 6 Tapped Primary 200 220 240v Sec 21 5v at 500mA 12 6 P amp P 2 6 i BATTERY CHARGER TRANSFORMERS 200 240v in put Nominal output ior 6 or 12y batteries 3 amps Bize approx 3 x 24 x 21 Brand New Price 21 P amp P 5 HIGH GRADE COPPER LAMINATE BOARDS 8 x 6 x xin FIVE for 10 P amp P 2 Open 9 5 30 Monday to Saturday STOCKISTS OF SINCLAIR EQUIPMENT Z 30 Amplifier 89 6 p amp p 2 6 Stereo 60 Pre Amplifier 9 19 6 p amp p 5 PZ5 Power Supply 4 19 6 p amp p 3 6 PZ6 Power Supply 7 19 6p amp p 3 6 IC 10 Integrated Circuit 59 6 p amp p 2
270. position shown its brass stemmed dust core being removed completely In connection with the coil care should be taken when soldering for excessive heat application will cause the polystyrene former to melt The length of screened cable to the receiver should be made no longer than required and it should be clamped firmly to the preselector base plate It is also necessary to fabricate a small metal bracket to carry the aerial socket SK1 Wiring associated with the slide switch Sla b is shown inset in the interests of clarity TESTING Initially a test meter set to read 0 10mA may be inserted in series with the battery and Sl When the switch is moved to In a current of approx imately 2mA should be noted Subsequently the test meter is removed and the preselector can be con nected to the receiver and aerial with which it is to be used With the preselector switch at Out a reasonably steady but weak signal should be sought on the receiver n the 14MHz amateur band and the S To RX aerlal socket SK2 Y Battery ve Cl not shown connects between X amp Y 2323 2 Peak e a iii o o o eae Batt eae ww o o m tn WWW A Fig 2 Layout of the completed pre selector 356 components list Resistors R1 15kQ R2 2 7k R3 1kQ R4 270k R5 3 3kQ Capacitors All W 10 1 C1 0 01uF ceramic C2 0 04uF tubular C3 100pF ceramic C4 0 014F ceramic C5 100p
271. ptimum v h f reception General Notes During the daytime particularly in winter at sun Spot maximum a considerable number of signals may be heard often above the m u f listings and predictions From the east forward scatter networks and rt t y may be heard from the USSR The most spectacular reception may be heard from the west particularly from the United States A large number of domestic ser vices such as waterworks undertakings gas suppliers private individuals and shops have 2 way com munication circuits be tween 30 and 45MHz and both base stations and mobiles can be heard in communication The most important fre guencies are 35 22 35 58 43 22 43 58MHz Paging stations are situated in most towns and in some cities there may be three or more A subscriber car ries a small radio receiver Output Ru tuned to the paging station If the subscriber leaves his office or home and is wanted urgently he is paged by the transmitter Each transmitter will repeat the message on a tape loop interspersed with its identification Consequently it is extremely easy to identify and locate these transmitters by the call sign and in most cases the name of the town is given components list Resistors R1 10004W R6 10kQ 4W R2 100k0 4W R7 15002 4W R3 120kQ 4W R8 22k 5W R4 470k 4W R9 2k03W R5 39k01W R10 270kS 4W VR1 5K WW pot R11 270kQ 4W All Resistors 20
272. put terminal had a 1uF capacitor to chassis and the coil RS 330 0 R1 amp 56k N 470pF To aerial Swi Aerial soos ARM on radio Y Tr1 C C1 LB AF117 0 1uF 0 01pF gt Ay ovi 6 8k A 0 1p F Fig 1 The circuit of the signal booster 364 switch terminal a lF capacitor to chassis This was due to the small signal producing practically no a g c voltage therefore the sensitivity of the set was maximum making the set acutely responsive to electrical interference The addition of this small r f amplifier made a vast improvement The increased signal input to the ferrite rod pushes the set hard into a g c cutting out the interference and making listening a pleasure once more E M IM LUE jl 2 dA Md NE a o EL md qu 2 we pd a sneer E sd di q FUN dove a v p I5 E T The signal booster may be mounted inside the existing cabinet as shown Hole for mounting screw fer Eis eje e Le e 9 dica EXC IE o IS Cofre tafe elie o of qo 6 o To aerial socket Fig 2 The component layout on Veroboard CIRCUIT DETAILS The circuit uses an AF117 transistor in the common emitter mode The base bias is set by the negative voltage at the junction of R1 and R2 and by the voltage across the emitter resistor R4 C2 the emitter by pass capacitor is to prevent the emitter resistor affecting the signal The signal is applied to the base via Cl R3 is the c
273. quency response Harmonic distortion Less than 1 at full output Signal noise ratio Better than 65db Speaker impedance 8 16 ohms Headphone impedance 8 16 ohms Bass control Variable 20 db at 100 Hz Treble control Variable 20db at 10 kHz Inputs Mic 1 amp 2 5 mV at 50 K ohms turntable amp 2 100mV at 1 meg ohm 50 ohm or 600 ohm mic inputs may be ordered at extra cost Size Front Panel 164 x 7 Cut out 154 x 6 Fuses A C 1 5 amp B S2 mounted on back panel PRICE 85 0 0 inc P amp P DISCOSOUND PRE 4 This is a four channel fully mixable pre amp with k separate treble bass and m gt master volume controls 8 P 4 and is completely self amp Powered All four inputs EEE o are by standard jack socket on the front panel with the addition of inputs 3 and 4 being duplicated on the back panel with two Paralleled outputs also featured for versatility in use Frequency response 30 20 000 HZ 3db Signal Noise Ratio 65db Size front panel 124 X 54 cut out required 11 x 44 Completely built and tested PRICE 18 0 0 inc P amp P DJ 30L PSYCHEDELIC LIGHT CONTROL UNIT cnc as e M 3 channel light control unit s that handles up to 1 000 T d pats per channel aseara m ME m ass middle and treble Am A a controls for full frequency n sz e separation Completely built and tested PRICE 37 10 0 inc P amp P DJ 70S INTEGRATED
274. r and commercial Morse within a month Normal progress to be expected Using scientifically prepared 3 speed records you automatically learn to recognise the code RHYTHM without translating You can t help it it s easy as learning 8 tune 18 W P M in 4 weeks guaranteed For details and course C O D ring s t d 01 660 2896 send 8d st mp for explanatory booklet to G3CHS BOX 11 45 GREEN LANE PURLEY SURREY aa a SEEN MY CAT 5 000 items Mechanical amp as EM and miaterials S A E K R STON Dept PW NEW MILLS Doa YUKA SELF SPAN qot these air drying GREY HAMMER BLACK WRINKLE M y w R CRACKLE finishes Other Yukon Air Drying Aerosol EE 16 013 at M carr poid include Zinc Chromate Clear Lacquer Metallics Grey Bive Bronze and Gold SO PROFESSIONAL THE VARAN AEROSOL WAY Yukan Aerosol sprayklt contains 6 ors fine quality durable easy instant spray No stove baking required Hammers available la grey blue gold bronze Modern Eggshell Black Wrinkle Crackle all at 15 M at our counter or I6 Il carriage paid per push button self spray can Also Durable heat and water resistant Black Matt finish 12 ozs self spray cans only 13 11 carriage paid SPECIAL OFFER I can plus optional rransferabl anap on trigger handle value 5 for 8 1 carriage pald Choice of 13 self spray plaln colours and pri mer Motor Car quality also avallable Please enclose cheque or erome
275. ra GOLRING GL69 fittel Gokirlug 64800 cartridge complete with le luxe base and cover Total list price 50 16 0 OUR Carr PRICE 39 20J TE 51 NEW 20 000 VOLT MULTIMETER with overload protection and mirror scale 0 6 60 120 1 2007 A C 0 3 30 60 300 800 3 000v7 D C 0 804 A 12 3000A D C 0 60K mec ohm 92 6 p AGE n MODEL AS 100D 100K O VOLT Sin mirrar cale Built in meter protection 0 3 12 60 120 300 600 1 200v D C 0 6 30 120 300 600 AL 0 10u A 6 60 300 In I9 amp 0 2K 200K PARUM 20 tis 17 18 12 10 0 P x P ain MODEL TE 200 20 000 O P V Mirror scale overload protec tion 0 5 25 125 1 000 V D C j 11 10 50 250 1 000 V 4 C 0 50 144 250 MA 0 60K 6 meg 4 20 to 62 db 75 Px P 2j MODEL TE 70 30 000 OPY 0 3 15 60 300 600 1900 DO 0 6 30 120 600 1200v A C 0 3014 3 30 300 nA 0 16K 160 K 1 8M 16 Meg Q 5 10 0 P amp P 3 MODEL PT 34 1 000 OPV 0 10 50 250 500 1 000 AC and ILC 0 I 100 500114 D C O 100K Q 39 6 P x P 1 6 Ali Mail Orders to 147 Church Street London W 2 Tei 01 262 6562 Trede supplied ton controla fully Interlocking Bize 13 4 10 above unit plate 43 helow Full instructions 13 19 6 Carr 7 6 MODEL TE 300 30 000 O P v 14 TE B00 20 000 Q VOLT GIANT MULTIMETER mirtor scale and overload protection fin full view meter 2 colour scale 0 2 5
276. ration Complete with calibra 100Kc s crystal calibrator 8 Meter Huge slide rule dial Operation 230V AC or 12V Oo Ss tion charts Excellent condition 19 10 0 DC Size 15 x 94 x Biin Complete with instruction manual 57 10 0 Carr Paid 100Kc s LELAND MODEL 7 BEAT CLASS D WAVEMETERS A crystal controlled hetero ilyne frequency meter covering 1 7 8 Me s Operation on 6 volts D C Edeal for amateur use Availahle in good used con or Carr 30 A crystal 39 6 extra FREQU ENCY OSCILLATORS R209 MK Il VARIABLE TRANSFORMERS B C 221 FREQUENCY 50002 or skQ Operation 200 190 AC Ge or Operation 200 250V A C COMMUNICATION RECEIVER Input 230v A C 50 60 cs METERS Bupplied in perfect order 12 10 0 Carr 10 11 valve high grade communication receiver Output variable 0 280 TE 65 VALVE VOLTMETER suitable for tropical use 1 20 Moe s on 4 bands ICA NUES AM CW FM operation Incorporates pre BENCH MOUNTING atest release High quality instrument cision vernier driver D F O aerial trim 1 amp 5 10 0 8 amp 14 1C 9 125 KHz 20 MHz with 98 ranges D C volts mer internal 24 amp 8 15 0 10 amp 18 10 0 Excellent condition 5 1 500v A C volts speaker and 9 amp 9 15 0 20 amp 237 0 0 Fully tested and checked and 1 5 1 500v Resistance 9v D C PANEL MOUNTING complete with calibrator charts HN m megohma A 240v A
277. rcel contains 5 ICs all new and perfect first grade device definitely not sub standard or seconds The ICs are all single silicon chip General Purpose Ampli fiers Regular price of which is well over 1 each Full circuit details of the ICs are included and in addition you will receive a list of 50 different ICs available at bargain prices 5 upwards with circuits and technical data of each Complete parcel only 1 post paid or List and all data 10 post free Credited when you order IC s value of 30 and upwards DISTRIBUTION PANELS Just what you need for work bench or lab 4 x 13 amp sockets and on off switch with neon warning light in metal box Takes standard 18 amp fused plugs Supplied complete with 7 feet of heavy cable 39 6 wired up ready to work plus 4 6 post amp insurance 5 amp 3 pin model 35 15 amp 3 pin model 45 STANDARD WAFER SWITCHES Standard Size 1i wafer asilver plated gt amp contact standard 1 spindle 2 long with locking Washer and nut d way D way 6 way Sway 9 way 10 way 12 way 1 pole 6 6 6 6 6 6 8 6 6 6 6 6 6 6 6 6 6 6 2 poles 6 6 6 6 6 6 6 6 6 6 6 6 6 6 10 6 10 6 3 poles 6 6 0 0 X 6 0 6 6 10 6 10 6 10 6 14 0 14 6 4 poles 6 6 8 8 6 6 10 6 10 6 10 6 10 0 18 6 18 6 poles 6 6 6 6 10 6 10 6 14 6 14 6 14 6 22 6 22 6 6 poles 6 6 10 6 10 6 10 6 14 6 14 6 14 0 26 6 26 6 7 poles 6 6 10 6 10 6 14 6 18 6 18 6 18 0 30 6 30 6 8 poles 10 6 10 6 10 6 14 6 18 6 18 6 18 6 34 6 34 6
278. rds the pre amplifier 351 Note gg scr ened leads mue e l y e M i M M eC a See text Microphone eae input ire if Guitar 1 LJ Guitar 2 a Guitar 2 Guitar 1 te volume volume C29 VRS a PAE Ag Optional wah wah Mounted on small heat sink on off see text To power module input 1 see text ad Fig 5 Circuit of the complete pre amplifier and its power supply View of the complete amplifier with the three circuit boards of the pre amplifier see Fig 5 at the left The power ampli fler module is in the centre with its own power supply unit to the right Behind the seem ingly blank hole in the very centre of the panel is the tremulant visual indicator lamp power supply the power output module and its power supply The chassis and front panel dimen sions with drilling and assembly details are given in Fig 4 Note how the finished chassis fits into and is secured in the amplifier compartment as shown in Fig 2D Pre amplifier Circuit The full pre amplifier and tremulant control circuit is shown in Fig 5 This is assembled on three s r b p circuit boards the three sections being marked round by the dotted lines The circuit function has 352 already been explained by means of the block diagram Fig 1 but the following general circuit description may prove useful The micropho
279. rked This operation should then be repeated with spot frequencies each side of 27MHz until the full coverage has been calibrated It should be stressed that the coil should not be bent or touched at all after calibration as this will certainly alter the readings USING THE INSTRUMENT When used to check a transmitter the field strength meter should be held about 18in from the transmitter and adjusted for maximum meter reading The dial setting can be compared with that obtained during calibration and this will indicate the transmitters approximate frequency See you at the R S G B Show August 19th 22nd THE MW coLumun ONES UGUST marks the end of the summer season on A the medium waves the effect of the longer hours of darkness being apparent even at the begin ning of the month North American stations are usu ally audible as early as 0030 hrs GMT Canadians appearing first Look for CBN 640kHz St John s Newfoundland CBH 860 Halifax Nova Scotia CION 930 St John s CHER 950 Sydney N S CHNS 960 Halifax CKBW 1000 Bridgewater N S CBA 1070 Moncton New Brunswick CKEC 1320 New Glasgow N S Stations from the East Coast of the United States appear a little later the more prominent being WNBC 660kHz WOR 710 WABC 770 WCBS 880 WINS 1010 all in New York City WHDH 850 in Boston WBAL 1090 Baltimore WCAU 1210 Philadelphia WKBW 1520 Buffalo N Y By 0230 hrs stations further inland may be heard WIR 760kH
280. ry Tape Record vutput Controls Volume Balance Bass Treble Attractive oiled walnut cabinet and brushed alu minium front panel List Price 28 7 0 LIND AIR PRICE 22 Gns P amp P 10 SPECIAL LIND AIR OFFER ROTEL 100 AMP STEREO AMPLIFIER Fully transistorised with all facilitles for the home hl fi system List price 45 LIND AIR PRICE 37 10 0 Carr 10 DE LUXE STEREO 9 HEADPHONES With soft rubber earpieces Imped ance 8 16 ohms Frequency re sponse 23 13 000 eps With lead and stereo plug VHFAIRCRAFT BAND CONVERTOR y When placed within lin Li of a MW band radio SES full coverage of VHF f Aircraft Band 108 135 Mk Mc s can be obtained All transistor 9v battery operation Fully tunable 8 imn x 7 section tele scopic aerial Size 4 x 2 x Ltin 19 6 si Eritish Made Solderless brcadboard panels for fast re liable component connections Single DeCs One 8 DeC with Control Panel Jlg and Accessories for solderless connections to controls etc with booklet Projects on 8 DeC giving construction details for a variety of circuits 29 6 P amp P 2 6 4 DeC KIT Four 8 DeCs with two Control Panels Jigs and Accessories and the book let Projects on B DeC all contained in a strong attractive plastic case Ideal for the professional user 5 17 8 P amp P 3 6 T DeC KIT 5 17 6 P amp P 3 6 Caariarid HI FI TURNTABLES 2023 TC w
281. s and diodes and res etc 10 boards at 10 plus 2 6 p p 25 boards at 22 6 pius 4 6 p p AERIALS new condition extending to 11 it fully open whip type 12 6 each plus 3 6 Pe Whip aerials 12ft collapsibie type used condition 10 each Plus 3 6 p p Bases for above 5 each plus 2 6 p p BARGAIN PARCELS 14lb at 29 plus 6 6 p p 281b at 55 plus 12 6 p p 561b at 90 plus 25 p p Contain pota Res Valves Diodes Tagboards Chassis Valveholders etc Good value save s Lucky Dip Service FURZHILL BEAT FREQUENCY OSCILLATOR 0 10 ke s 110 250 volt Good condition complete with spares 25 10 0 plus 25 p p VHF Receiver Type 715 less crystal 60 100 Mc s can be operated on 2 or 4 meters or made tunable 12 volt input not tested complete with valves and speaker 3 0 0 plus 1 p p VIBRATOR POWER SUPPLY TYPE 68 by BBC for 89T R Small compact 12V input gives 250V DC at 80mA and 12V output Good condition 25 plus 7 6 p p MOBILE POWER UNITS by PYE for the C12 T R Power output is 400V DC at 140mA and 300V DC at 100mA Good condition 23 10 0 plus 1 p p INSULATION TESTERS Bench and fieldwork speed clutch new condition complete with leather case 500V 500 megohms 20 0 0 plus 12 6 p p Also 1000V 1000 megohms with case 23 0 0 plus 12 6 p p CRYSTALS AS NEW Hc 6u 5 345 5 055 5 030 5 005 4 945 4 875 4 840 4 795 4 580 4 660 4 520 4 510 2 300 2 295 Kc s and 10 x J465 Kc s 1
282. self addressed en velope must accompany each entry All entries submitted will be considered by a panel of judges and the Edltor s decision on all matters arising will be final The Editor will require authors of winning entries to submit the equipment to him mediately on request for final assessment by the panel 8 Employees and staff of Practical Wireless are not eligible for entry to this competition 9 The winner of the competition will receive and retain outright the Practical Wireless Designer s Trophy 1970 Other prizes will be awarded to the best run ners up Any article published wil be paid for at normal rates h N eo md ENTRY FORM PAGE 354 390 Fig 2 witching arrangements for 2 band operation of the b a and p a stages Lock v f o and buffer doubler cores with 6BA nuts On 80m S2 shorts out one half of the tank coil and is a toggle switch fitted to the panel immediately behind the coil Receiver Coils Readily available Denco coils are used for 160m and 80m in the receiver section Range 2 coils for 160m and Range 3 coils for 80m Blue coils are required for the aerial circuit Yellow coils for the mixer grid and Red coils for the oscillator The Range 2 Blue and Yellow coils each have 32 turns removed from the tuned winding Count these as they are unwound and re solder the wire to the pin The Red
283. size 10 x 42 x 4 Fitted large speaker Jack Socket and Volume Control Many uses e g Radio Kit Amplifier Intercom Record Player Public Address or even Crystal Set Amplifier OUR PRICE ONLY 7 P amp P 4j6d EXTENSION SPEAKER CABINET The same Cabinet that houses our Amplifier ONLY 26 P amp P 3 9 with fitted Speaker 34 P amp P 3 6d Cheques Postal Ordera to Dept P W Galleon Trading Co 208A Lodge Lane Rom ord Essex Stella Nine Range Cases Manufactured in Black Grey or Blue Stelvetite and finished in Plastic coated Steel Morocco Finish with Aluminium end plates Rubber feet are attached and there is a removable back plate There is also a removable front panel in 18 s w g Alloy Now all Aluminium surfaces are coated with a strippable plastic for protection during manufacture and transit All edges are polished LIST OF PRICES AND SIZES Width Depth Height 6 Height 74 Height s d sedi std 61 3j 15 0 1845 0 iir 1076 6l 4 16 3 1 6 lI CSO 8i 3j 18 0 BI ESOM 3 14 550 8i 6j 1 5 On 150 9 117 0 101 7 1314176 2 7 81 2 1650 12i 3j 1 5 4 0 BETTO 117 6 12i 54 1 14 0 2482 0 2 135 o 124 8 Sues 0 2L 6 215 EG 14i 34 110 70 1 14 6 9 27228 0 14i 9 2 11 6 39 LL 3 1070 163 6j 2 6 0 2u5 6 347 9 16i 10 3 00 318 0 4 6 O Cases Post 4s 6d per order Discounts available on quantities CHASSIS in Aluminium Stand
284. splay in full daylight 2N1306 5 acy Rio MEE aio gt Bandwidth 10 c x 10 me s Triggered sweep pre set at 2N1307 6 ACY22 18 ESTAS 5i ES 1 2 5 10 30 100 300 1000 3000 mec per struke Free 2N1308 7 6 ADI4O j pi Er running tine base 20 cjs to 2000ke s with built in 2N1308 9 6 A is ewe rh ZENER DIODES 90 100 kel Dur TRO ERA T 2N1756 18 ADLN 9 BSY6 4 6 BZY88 series froin 3 3V to 9 1V 5 40muW 3 6 each o ec E directly calibrated in valts 2N2147 14 8 AD102 x TES ise BZY 54 series froui io Nato CUN i57 au ve sai j 216 AFII4 D814 series from 7 5 V to 13 0V 109 m each Input avo ae SNIN e AFI1la 8 0C2 18 D815 bi foni 4 V to 18 0V 10 8 Watts 7 6 each dixi el pee QN2218 7 8 AFli6 5 8 OCo3 186 D816 series from 29 V to 47V 10 5 Watts 7 6 each p os UIT E art E 2N2210 8 6 AFIIZ7 4 6 OC24 15 D817 series from 56V to 100Y 10 6 Watts 7 8 each fa gt gt gt M n rud M A c eee a Outlines BZY series minuiature wire ended a 5 gt i 2 OC25 14 6 D814 Top Hat type cia S CEL 1CP8I DM E 2N2005 10 AP 127 a 0C29 14 9 D815 D817 stud mounted supplied complete 3v heater A ee 500v Sensitivity Y plates AME 4n ARN Hu Ono Tips rn PENAS mer TESTI A3 pU REA MU cae Lu eal xui E t lt ireri nearest standard voltage wi abs eft x platex 52vjeni typical Y plates suitable for 0N9995 h 8 AF239 10 0C36 12 6 eirca voltage requireri t s assymmi
285. st frequency range probably about 1 5 4MEHz so that the crystal will oscillate initially on its fundamental frequency rather than on an overtone mode If it should work on such a mode further confusion will arise if an attempt is made to measure the crystal frequency because of the fact that overtone frequencies are not integral multiples of the fundamental frequency On say the fifth overtone the measured frequency may be several kilohertz different from the fundamental frequency multiplied five times Alternative method If a g d o is not available a signal generator or a frequency meter may be used using the set up shown in Fig 4 The voltmeter should have a high resistance of about 10 0000 volt or a general purpose meter may be used on a low voltage range A valve voltmeter will be more sensitive and should be used in preference to a conventional test meter The procedure is to tune the signal generator from its lowest frequency about 1MHz upwards until a deflection is noted on the meter In this case the peak indication is the point at which the crystal is resonant with the applied signal If the calibration of the signal generator is not to be relied upon then an external receiver can be used to measure the frequency as before The author has found in practice that much too much faith is placed on the calibration of signal generators which do not have their own internal calibration facilities 50pF OAS Signa
286. struction details and parts list free with kit 1 6 B A E GENERAL PURPOSE HIGH STABILITY TRANSISTOR PRE AMPLIFIER For P U Tape Mike Guitar etc and suitable for use with valve or transistor equipment 9 18v battery or from H T line 200 300v Frequency response 16Hz 25KHz Gain 26dB Solid encap sulation size 11 x 11 x 2 Brand new complete with instructions Price 17 6 P amp P 2 6 SPECIAL PURCHASE E M I 4 SPEED PLAYER Heavy 8 in metal turntable Low flutter performance 200 250v shaded motor 90v tap Complete with latest type lightweight pick up arm and mono cartridge with t o stylil for LP 78 ONLY 68 P amp P 6 6 a mb O E TT TS I m CODD NN AED O QUALITY RECORD PLAYER AMPLIFIER MK II A top quality record player amplifler employing heavy duiy double wound mains transformer ECC83 ELB4 E280 valves Separate Bass Treble and Volume controls Complete with output transformer matched for 3 ohm speaker Size 7in wide x Sin deep x Gin high Ready bult and tested PRICE 75 P amp P 6 ALSO AVAILABLE mounted on board with output transformer and speaker ready to flt into cabinet below PRICE 97 6 P amp P 7 6 DELUXE QUALITY PORTABLE B P CABINET ME II Uncut motor board size 14 x 12in clearance Zin below 5pin above Will take above amplifier and any B B R or GARRARD changer or Bingle Player except AT60 and SP25 Size 18 x 15 x 8in PRICE 79 6 P amp P 9 6
287. t the strips in six places indicated by X along strips D E F G I and J Aluminium L bracket 2x 4 x in TOTO On O a 6 i5 4 39 Rd foo a8 7 g 9 4 9274 Fig 2 Circuit board showing breaks required in conductor strips The Veroboard is then turned over and with the conductor strips on the underside the various small components are positioned as shown in Fig 3 It is desirable to use modern high grade miniature resistors and capacitors and to test them prior to soldering them into position A piece of 18s w g aluminium 5 x 2iin is required for the panel and the Veroboard is fixed to this using a small L bracket with iin sides and approximately 2in in length The panel is connected to earth by the link wire indicated in Fig 3 The panel also carries the function switch attenuator and outlet socket these components together with essential dimensions and the remainder of the wiring can be seen in Fig 4 2a 4 9 6 4 8 9 3130 M Om 1 T4 15 6 Veroboard 3 4 x 1 in approx Ofin matrix Fig 3 Component layout on top of circuit board 394 components list Resistors R1 6 8k R7 R2 6 8k 2 R8 R3 10k R9 R4 100k R10 R5 3 9k R11 R6 6 8k R12 All W 10 VR1 5k skeleton pot VR2 50k miniature pot Capacitors C1 5000pF ceramic C6 C2 5000pF ceramic C7 C3 5000pF ceramic C8 C4 T5pF ceramic C9 C5 10uF12VW elec 0 01uF ceramic 0 01uF ceramic 0 01uF ceramic 150p
288. t from this Course but it teaches the real thing Bite size lessons wonderfully clear and easy to understand practical projects from a burglar alarm to a sophisticated Radio set here s your chance to master basic Radio and Electronics even if you think you re a non technical type And if you want to carry on to more advanced work B I E T has a fine range of Courses up to A M LE R E and City and Guilds standards Send now for free 164 page book Like to know more about this intriguing new way to learn Radio and Electronics Fill in the coupon and post it today We ll send you full details and a 164 page book ENGINEERING OP PORTUNITIES Free and without any obligation To B I E T Dept 372B ALDERMASTON BERKS ALDERMASTON COURT Practical Radio amp Electronics Course Please 330 I would like to know more about your i send me full details and FREE 164 page book ij 1 sain ad age matching circuit for 15 ohms using only 3 resistors 54 plus 4 pp i approx output Transformer 2in x Zin x 1 in mounted on aluminium 455Kc s FM LF PANEL Brand new but faulty 6 transistor panel 60 UNTESTED MIXED TRANSISTORS 5 plus 1 pp Listen to the world with Eddystone When you own an Eddystone communications receiver you have the broadcasting world at your finger tips wherever you happen to be on land or at sea The reputation these sets have a
289. t has been finished Alignment The alignment of the converter is simple Inject a low level modulated signal at 5MHz to pin 2 Valve 3 Adjust the core of L5 to give maximum reading on the main receiver S meter or for maximum sound output with the age switched off Now shortcircuit the oscillator section tuning gang to Aerial LI 12 13 Vi R9 C7 V2 C11 R va Bottom view of converter with identification of major components 374 4 L5 Fig 3 Modified circuit incorporating an r f gain control chassis and inject the 5MHz signal to pin 2 of Valve 2 Adjust the core of L4 to give maximum readings as before Remove the shortcircuit and adjust C11 to approximately one third value Find a signal such as Crystal Palace sound on 41 5MHz and align L2 to give maximum signal Alternatively inject low level signals from a signal generator at about 40MHz and adjust the core of L2 Check that the range 30 50MHz is covered then seal C11 with wax to prevent movement Denco recommend that 5OpF tuning capacitors are used but at the time of construction a 3 gang unit of these values was not available hence the use of a Jackson 3 gang 75pF unit was necessary which tends to increase the l f coverage below 30MHz It may be found that performance falls off below 26MHz due to the low v lue of C11 Increasing its value to improve the l f coverage tends to deteriorate the h f performance at 50MHz So C11 should be set for o
290. ta Circuits and Pians for Building Ep 10 Advanced Designs PHOTOELECTRIC BURGLAR ALARM INVISIQLE BEAM TYPE INVISIBLE BEAM OPTICAL KIT Everything needed except plywood for building 1 Invisible Beam Projector and 1 Photacell Receiver as illustrated Suitable for all Photoelectric Burglar Alarms Counters Door Openers eic CONTENTS 2 lenses 2 mirrors 2 45 degree wooden blocks Infa red filter projector lamp holder building plans etc Price 19 6 Postage and Pack 1 6 U K Commonwealth Surface Mail 2 Air Mail 8 LONG RANGE INVISIBLE BEAM OPTICAL KIT CONTENTS As above Twice the range of standard kit Larger Lenses Filter etc Price 29 6 Postage and Pack 1 6 U K Commonwealth Surface Mail 2 6 Air Mail 10 JUNIOR PHOTOELECTRIC KIT Versatile Invisible beam Relay less Steady light Photo Switch Burglar Alarm Door Opener Counter etc for the Experimenter CONTENTS Infra Red Sensitive Phototransistor 3 Transistors Chassis Plastic Case Resistors Screws etc Full Size Plans Instructions Data Sheet 10 Advanced Photo electric Designs Price 19 6 Postage and Pack 1 6 U K Commonweslth 2 Air Mail 4 JUNIOR OPTICAL KIT CONTENTS 2 Lenses Infra red Filter Lampholder Bracket Plans etc Everything except plywood to build 1 miniature invisible beam projector and photocell receiver for use with Junior Photoelectric Kit i Price 10 6 Post and Pack 1 6 U
291. ta sent with two more 64 10 80 25 80 16 80 25 100 64 125 4 195 10 EE dia eee 200 O to ZM R se 125 16 160 2 5 200 6 4 200 10 250 4 320 2 5 320 6 4 Dual gang linear 4 7K Q to 22M Q 8 8 WAVECHANGE SWITCHES pU ura Dual gang log 4 7K Qto22MQ 8 6 S Log antilog 10K 47K 1M 2 only 8 6 LONG PINDLES Any type with A D P mains switch extra 2 3 LARGE CAPACITORS High ripple current types 1000 25 85 6 1000 50 8 2 1000 100 16 3 2000 25 7 4 2000 50 11 4 2000 50 11 4 2000 100 28 9 2500 64 15 5 2500 70 19 8 5000 25 12 6 5000 50 21 11 5000 100 88 8 10000 15 17 10000 25 24 6 10000 50 44 10000 70 61 1P 12W 2P 6W SP 4W 4P 3W 4 9 each SLIDER SWITCHES D P D T 3 each Please note only decades of 10 22 and 47 are available within ranges quoted CARBON SKELETON PRE SETS Small high quality type PR linear only 100 Q 220 Q 470 Q 1K 2K2 4K7 10K 22K 47K 100K 220K 470K 1M 2M2 5M 10M Q Vertical or horizontal mounting 1 each COMPONENT DISCOUNTS 10 on orders for components for 5 or more 15 on orders for components for 15 or more No discount on nett items POSTAGE AND PACKING Free on orders over 2 Please add 1 8 if under Overseas orders welcome carriage charged at cost NEON INDICATOR LAMPS all 200 250V Square bezel red only 3 9 Round chrome bezel red amber clear 4 9 each Toggle switches 250V a c 1 5A chrome dolly and chrome milled nut S P S T 3 9 8 P D T
292. tage of the j chances you are now missing x HOW irrespective of your age education i or experience YOU can succeed in any branch of Engineering 164 PAGES OF EXPERT CAREER GUIDANCE PRACTICAL INCLUDING EQUIPMENT TOOLS Basic Practical and Theore The specialist Elec i tic Courae for beginners in HA Radio T V Electronics Etc en Division of E A M I E R E City amp Guilds E NOW offers you a pe It x M Radio Amateurs Exam Advanced Radio Gen Advanced Electronic Eng CS Cope nate ing at home with Radio Radio amp TV Gen Electronic Eng ractical Radio practical equipment NOS i Radio amp Television Servicing d Servicing TV Eng Applied Electronics Prac Practical PECTS it Ask for details RADIO ENGINEERING Telecommunications Sound Recording Automation Practical Radio Radio Amateurs Exam ELECTRICAL ENG Advanced Electrical Eng ELECTRONIC ENG Electronics Radar Tech Frequency Modulation Transistors MECHANICAL ENG Advanced Mechanical Eng Gen Mechanical Eng R T E B Certificate Electronica Engineering Automation real laboratory train Gen Electrical Eng Maintenance Eng Diesel You are bound to benefit from reading ipi o Met Drguedis rs T Le To uer ENGINEERING OPPORTUNI nat A cet fi ork Weidaing 33 iis Religion a idi Eng
293. th an output of 14 watts from 2 E EL84s in push pull Super reproduction of both music and gible hum Separate inputs for mike and and announcements 3 to follow each other Fully shrouded section wound output transformer to match 3 15 Q speaker and 2 independent volume controla and separate base and treble controls are provided giving good lift and cut Valve line up 2 EL84s ECC83 EF86 and EZ80 rectifier Simple instruction booklet 9 8 Free with parts Ali parts sold separately ONLY 7 9 6 P amp P 8 6 Also available ready built and tested complete with std input sockets 9 5 0 P amp P 8 6 BRAND KEW TRANSISTOR BARGAINS GET 15 Matched pair 15 V15 10p 10 OC71 5 0076 6 AF117 3 6 2G339 NPN 3 Set of Mullard 6 transistors OC44 2 0C45 ACI28D matched pair AC128 25 ORP12 Cadmium Bulphide Cella 10 6 All post free Please write clearly PLEASE NOTE P amp P Early closing Wed p m 170 HIGH ST MERTON LONDON S W 19 Tel 01 540 3985 CHARGES QUOTED APPLY A few minutes from South Wimble OVERSEAS ORDERS CHARGED don Tube Station 380 SEND STAMPED ADDRESSED ENVELOPE WITH ALL ENQUIRIES EXTRA COLIN RICHES ARTHUR DOW everyday use in the jargon of the electronic engineer it is perhaps opportune to look back at the work of that early pioneer in radio communication Professor Heinrich Hertz and to consider whether or not the perpetuation of his name as a techn
294. th d c poten tials supplied the lowest possible battery voltage should be applied to the transistorised unit com patable with adequate amplification Hu ide To S1 ery area O EM Nasa m am mi epi ei for your a E miniature m CN 15 Watts ideal for miniature and micro from soldering LESE oco A tas Td 3 4 AA its avai efrom mim up to us gi Iron For 240 220 110 50 or 24 volts a 24 amp Complete precision This kit in a rigid plastic O r 9 mem tool box contains Model CN 15 watts miniature iron fitted ve bit Interchangeable spare bits dy A soldering kit p G 18 watts Fitted 3 32 bit for miniature work on production lines Interchangeable spare bits 1 8 3 16 and 1 4 availabie For 240 220 or 110 volts 36 ere PSP PRECISION MINIATURE SOLDERING IRONS Felticleaning pad i Antex Mayflower House Plymouth Devon Stand for soldering iran no Telephone Plymouth 67377 8 N E20 watts Fitted with 1 4 bit PLUS 36 page booklet on From Electrical and Radio Tele oder OS ad OCO interchangeable spare bits 3 32 1 8 How to Solder a mine Shops or 3 16 available For 240 220 110 of information for amateur send cash T Please send me the Antex cotour volts 36 sit E and professional to Antex catalogue F Please send me the following irons Quantity Model Bit Size Volts Price E CEDCnCADDDES soset
295. transistor 2 muting panels with Schmitt trigger circuit to operate the gate on the audio panel 8 transistors in all Supplied with full circuit 22 6d plus 2 6 pp usually low in gain 12 6 plus 1 6 pp HAND TELEPHONES Brand new radiotelephone type press to talk handsets 12 6 plus 1 6 pp VHF AERIAL C O RELAYS Used but OK 6 or 12v 4 plus 1 6 pp 60 UNTESTED MIXED DIODES 2 6 plus 1 pp USED TESTED VALVES 12AX7 ECC83 2 6 6BJ6 1 6 6AQ5 EL90 2 6 ECF80 2 6AT6 1 6 1 ALSO VARIOUS VHF EQUIPMENT IN STOCK ih S A E AND 6d STAMP FOR LISTS 21kW FAN HEATER Three position switching to suit changes in the weather Switch up for full heater 2 kW switch down for halt heat ljk W switch central blowa cold for summer cooling adiustable thermostat acts as auto control and safety cut out Complete kit 4 8 15 0 Post and ins 7 6 FLUORESCENT CONTROL KITS Each kit comprises seven itenis Choke 2 tube ends starter starter holder and 2 tube clips with wiring instructions Suitable for nornial fluorescent tubes or the new Grolux tubes for fish tanks and indoor plants Choker are super silent mostly resin filled Kit A 15 20 w 18 8 Kit B 30 40 w 19 6 Kit C 80 w 25 6 Kit MF1 is for 6in 9in and 12in miniature tubes 19 6 Postage on Kits A and B 4 6 for one or two kits then 4 6 for each two kits ordered Kits D and E 4 6 on first kit then 3 6 for each kit ordfred Kit MF1 3 6
296. ttained is proof of their excellence and reliability and at Imhofs there is a special Eddystone department where you can see hear and compare all models listed here Same day despatch to any part of the world free delivery in the U K plus after sales service for which Imhofs and Eddystone are world famous EDDYSTONE EB35 Mark II broadcast receiver AM FM transistorised A high performance all band receiver can also be used as a Hi Fi tuner Powered by 6 SP2 torch cells or with Type 924 power supply unit from AC mains 88 12 3d Also stereo model 97 10 9d EDDYSTONE 940 13 valve communications receiver connoisseur s instrument combining Professional appearance with performance has a world wide reputation two RF stages ensure high sensitivity 159 0 0d EDDYSTONE EC10 transistorised communications receiver An en thusiast s receiver at a modest price Embodies features usually only found in much more expensive designs Powered by 6 SP2 torch cells or Type 924 power unit AC 62 10 0d EDDYSTONE EC10 Mark H transistorised communications receiver A de luxe version of this famous design now incorporating S meter and limited fine tuner 74 10 0d EDDYSTONE EA12 Ham Band receiver Built to professional stan dards but specifically for the amateur enthusiast High sensitivity for all reception modes CW MCW AM and SSB FSK adaptor available as ancillary 205 0 0d There is an Eddystone Communications receiv
297. u think about t v i and that tiny splinter of copper you call an earth doesn t it Lots of inquisitive ears have been flapping about this month and despite the warm weather many people sent in multiple logs My tbanks to all those owners of hot swetty little lugs who persisted and perspired You re doing a grand job slaves More mighty magnificence from the majestic Master Moore John who lives in Leicester bagged GM and GW on topband On 14MHz the CR100 2 at u and 130ft long wire reported signals from AXSLC AX LD Macquarie Island CEQAE HK4AD HRIKAS HR2WTA KH6BX YN2EC YVAYC 8P6AH A quick pilfer round the pertinent portions of 21MHz raised CN8AH ELIB EL2BZ F RT FC P JAIEOD JA2NPC JA6YSS TF3BV VP9BY VU2OLK YAIEXZ YAIGNT 5H3KA 5Z4DW 9E3USA 9HIBE 9VIPA Ten metres a m was heard from LU6DRB and on s s b HK3AVA KV4AD VU2BEO ZE2JA ZS6AUD 5Z4LS John is hoping to listen on 432MHz soon when he gets a homebrew converter perking and takes delivery of a 14 element skybeam Cor think of the pleasure all those little prongs will give the birds Roger Boyd is located in Victoria Park Western Australia and has the distinction of sending the most DX log received this month The rig is a Trio 9R 59DE and choice of 20 metre dipole or a 25ft vertical His log for 7MHz reads DJQJE DKICU DL6WE DL8MM EA4KY G3VYF P HB9ADQ IIBAF JA2VGQ JASTL OZS5MV PY7BPD SP6DVB UAIIG UY5YS YTIBCD So if t
298. ughout the entire audio range Double wrapped attraet ively boxed As min 1 8 250 P V Q 5 6 52 1200 P V C 12 6 amp l x P 1 7 3 450 POLYESTER 7 8 53 1800 POLYESTER 22 8 CASSETTE HEAD CLEANER 31 600 Dor ATER ante 5 2400 POLYESTER ous Removes unwanted deposita from VE tape heads V C amp P 5 600 1200 P V C 12 its 5 1800 Fits all cassette recorders 1 1 6 P 900 PVC 10 P V C 15 5 5 1200 POLYESTER 15 7 2400 POLYESTER 25 1 TAPE SPOOLS 3 1 5 51 7 1 9 7 3600 POLYESTER 50 All cassettes can be supplied with library cases Post and Packing 3 14 6 527 16 7 2 3 reels and over Post Free at 6d extra each PREMIER RADIO 7 a 23 TOTTENHAM COURT ROAD LONDON W1 Tel 01 636 3451 a LS YOURS FREE LL The New Picture Book way of learning B ASIC ELECTRICITY 5 voLs ELECTRONICS 6vors You l find it easy to learn with this out standingly successful NEW PICTORIAL METHOD the essential facts are explained in the simplest language one at a time and each is illustrated by an accurate cartoon the latest research into simplified learning techniques This has NE that the PICTORIAL APPROACH to learning is the quickest and soundest way of gaining mastery over these subjects type drawing The books are based on TO TRY IT IS TO PROVE IT EM ESEHEENENHPEHEHEHNHNENHEHBEBHENHIEINU To The SELRAY BOOK CO 60 HAYES HILL HAYES BROMLEY
299. uminium 18 s w g Pieces as in Fig 4 Aluminium angle 3 x jin Approx 6 ft Aluminium angle 2 x Zin Approx 2ft Nuts and screws Various 4 BA Planed batten 2 x fin Approx 16ft Square beading 4 x tin Approx 10ft Carrying handles 2 Sundry woodscrews Covering material Felt tin thick if required 353 If the microphone transformer is not required it is not included in the pictorial diagrams to follow later then simply connect the input jack to Cl as shown at the starred points Note that the impedance of the microphone input without a transformer is approximately 100kQ and is not suitable for crystal microphones The guitar pre amplifier Tr4 and Tr5 is similar to the microphone pre amplifier except that a treble lift control VR6 has been incorporated which provides approximately 15dB lift at 10 000Hz The output from the guitar pre amplifier is divided across R31 and the Ld r and routed to the tone tremulant ciricuit input transformer I3 and on to the mixing pre amplifier Tr8 and Tr9 via R38 The transformer T3 must be the one specified in the components list and connected exactly as shown The circuitry drawn in dotted line C29 VR9 is for the optional wah wah effect further details of which will be given later The phase shift oscillator Tr3 is quite straight forward but note the optional dotted line circuitry for a foot control tremulant on off switch which can be connected via a jack socket on the front pan
300. used In Makers cartons 8 19 each plua carriage at cost We suggest you allow 30 for this any change will be returned to Horstmann Time and Set Switch A 15 atup Switch Just the thing if you want to come home to a warm house without It costing you a fortune You can delay the switch on time of your electric fires etc up to 14 hours from setting time or you can use the switch to give a boost perlod of up to 3 hours Equally suitable to contro processing Regular price probably around 5 Special snip price 29 8 p amp Ina 4 8 OUT OF SEASON BARGAIN mentos 3kW TANGENTIAL HEATER UNIT This heater unit is the very latest type most etfiolent and quiet running ls aa btted in Hoover and blower beaters costing 15 and more We hare a few only Comprises motor impeller 2kW element and 1kW element allowing awltching 1 2 and 3kW and with thermal safety cut out Can be fitted into any metal line case or cabinet Only need control Bwitoh 59 6 2kW Model as above except 2 kilowatta 89 6 Postage and insurance 6 6 Don t miss this MOST AMAZING BARGAIN PRINCESS AUTO CHANGER The most amazing bargain everl A brand new Auto change record player for less than the price of a single player due to a frustrated export order we are able to offer the Balfour Princesas 4 speed Autochanger a really fine machine at about one third of its regular price The Balfour has two uniqu
301. ving a finx density of 14 000 gauss and a total flux of 145 000 Maxwells Bass resonance 45 o p s Rated 20 watts Voice coils 9 or 8 or 15 ohms Module kit 30 17 000 c p s with tweeter crossover baffle and BAKER GROUP SOUND SPEAKERS POST FREE Group 25 Group 35 Group 50 12in 12in 15in wm T wu I somi 19 TEAK HI FI SPEAKER CABINETS Fiuted wood front For 10 or 12in round Loudspeaker 9 0 0 For 18 x 8iu round Loudapeaker h For 10 x 6in or Shin round Loudspeaker 24 0 0 LOUDSPEAKER CABINET WADDING 18in wide 3 It Horn Tweeters 2 16kc s 10W 15 ohm 29 6 De Luxe Horn Tweeters 2 18 Kc s 15W 16 ohm 59 6 MOVING COIL cone tweeter 8 ohm 19 8000005 CROSSOVERS 8 or 8 or 15 ohm 19 SPECIAL OFFER 80 ohm 2 in 21in dia 35 ohm Sin 25 ohm 3in dia 6 x in B x Sin 8x bin 17 6 EACH 15 ohm Szin dia 7 x din 8 x Bin TYPE 8 ohm 6 x 4in 3 ohm 21in Sin Sin 5 x Sin 7 x din LOUDSPEAKERS P M 3 OHMS 8 in 22 6 8 x Din 25 8 x Skin 18 Sin 85 10 x Gin 38 Bin WOOFER 8 watts max 20 10 000 cps 8 or 15 ohm 38 ELAC 8 in De Luxe Ceramic 8 ohm or 15 ohm 50 SPECIAL OFFER FAMOUS RICHARD ALLAN LOUD SPEAKERS 8 or 10 or 12in Twin cone 8 or 15 ohm 39 8 OUTPUT TRANS EL84 eic 5 MIKE TRANS 50 1 6 SPEAKER COVERING MATERIALS Samples Large 8 E SOUND ACTIVATED PSYCHEDELIC LIGHT BOX Fascinating light patterns of Green Blue R
302. was heard by the writer as recently as the 13th of June this year Older DXers may care to look for CBO 910kHz in Ottawa CBM 940 Montreal KDKA 1020 Pittsburg WBZ 1030 Boston WBT 1110 Charlotte North Carolina WHAM 1180 Rochester N Y A few old timers have changed callsign WEAF New York City is still on 660kHz 454m but is now called WNBC WLWL Cincinatti which once had a power of 500kW is now WLW 700kHz with a modest 50 kW It is interesting to note that new 50kW transmitter installed at WOR New York City 710kHz during 1968 replaced one which had been in service con tinuously since 1922 CHARLES MOLLOY 365 checkin surplus crystals NO SOO no Ae 2000 cue O ago Be able cheaply and in large quantities many of them are not marked with their frequencies or at best are marked with a code or channel number While it is possible to get information to decode these numbers it is far simpler in the long run to make a direct check on the crystal to determine its fundamental frequency A LTHOUGH surplus crystals are readily avail In some cases the frequency indicated on the crystal holder is an operating harmonic frequency and not the fundamental So once again the necessity arises to find the fundamental by direct means It is possible to build a simple transistorised oscillator using the Pierce circuit so that just about any crystal plugged into it will oscillate But to determine the fundam
303. with full wave recti fication giving ade quate smoothing with negli gible hum Valve line up 2 x ECLS86 Triode Pentodes 1 x EZ80 as full wave rectifier Two dual potentionmetera are provided for bass and trebie control giving bass and treble boost and cut A dual volume control is used Balance of the left and right hand channels can be adjusted by means of a separate Balance control fitted at the rear of the chassis Input sensitivity is approxi mately 300m v for full peak output of 4 watts per charnel 8 watts mono into 3 ohm speakers Full negative feedback in a carefully calculated circuit allows high volume levels to be used with negligible distortion Supplied complete with knobs chassis size ll w x 4 d Overall height including valves 5 Ready built and tested to a high standard PRICE 8 gns P amp P 8 4 SPEED RECORD PLAYER BARGAINS Mains models All brand new in maker s packing SPECIAL OFFER Famous GARRARD 3500 fitted Sono tone 9TAHCD Diamond Stereo Cartridge List price over 10 Limited Number at 10 Carr 8 6 LATEST B S R C109 A21 4 SPEED AUTOCHANGER With latest mono compatible cartridge 6 19 6 Carr 6 6 With stereo cartridge 7 19 6 Carr 6 6 LATEST GARRARD MODELS All types available 1025 2025 SP25 3000 AT60 etc Send 8 A E for latest Prices PLINTH UNITS cut out for Garrard Models 1025 2025 2000 3000 AT60 BP25 With rigid transparent plastic cover Npecial design
304. xpensive instrument for the handyman Oper ates on 9v battery Wide easy to read scale 800kHz modulation 5i x Of x gjin Complete with instruc not supplied for fixed frequency operation In corporates 4 INTEGRATED CIRCUITS Built in speaker and illuminated dial Squelch and vol ume controls Tape recorder output 75 aerial input Headphone jack Operation 230V A C SOLARTRON CD 71152 12V D C Neg earth 287 10 0 Carr 10 Le Double Beam Oscilloscopes TELETON CR 10T AM FM STEREO TUNER AMPLIFIER A new model from Teleton 31 solid Btate devices 4 4 watt output Inputs for ceramlc crystal cartridge Frequency range AM 540 1600K Hz FM 88 108MHz Automatic FM Stereo reception Stereo Indicator tions and leads 7 19 6 encara Tunis fonction pesce P amp P 4 one an volume controls AFC switch Atereo headphone socket ED EOD Size 1327 x 34 x 94 approx HEADPHONES PRICE 434 0 0 Carr 7 6 F eatures unique mech anical 2 way units and fitted adjustable level D C to 9 Mc s Perfect order 65 Carr 50 TO 3 PORTABLE OSCILLOSCOPE Sin tube Y amp Sensiti vity 0 1v p p CM Band width 1 5 cps l 5 MHz Input imp 2 meg N 25pF X amp sensitivity 0 9v p p CM Bandwidth 1 5 eps 800KHz Input imp 2 meg 2 20pF Time base 5 ranges 10 cps 300 KHz CLEAR PLASTIC PANEL METERS con tte ls sis iin Synchronization Internal First grade quallty Moving Coil pane
305. xt element in this series of sub miniature 4 pin i c s it is a general purpose direct coupled amplifier for a f or i f applications until then this attractive little unit should provide food for thought and work for the soldering iron The unit is available from Jermyn Industries Vestry Estate Sevenoaks Kent or Henrys Radio Ltd who can also supply the transistor MPS A70 Eg 978 RADIO ENGINEERING AND COMMUNICATIONS EXHIBITION if you re in Town Aug 19 22 pop along to the above exhibition and see our latest designs Venue is Royal Horticultura Society s New Hail Greycoat Street Westminster London S W 1 Exhibits include Light Beam Phone Vibrasonic Guitar Amp Organ Pedal Bass Unit COME AND VISIT US AT THE 1970 INTERNATIONAL AUDIO FESTIVAL amp FAIR OLYMPIA LONDON W 14 OCTOBER 20th 24th 10 a m 9 p m each day The PRACTICAL WIRELESS stand will feature many constructional features PRACTICAL TELEVISION SEPTEMBER CONSTRUCTOR S SINGLE STANDARD I F STRIP A vision and intercarrier sound i f strip is not an easy item for the constructor with the high gain and wide bandwidth involved This design has been very care fully devised by Keith Cummins with the problems of enthusiasts in mind to go with his 625 line receiver Having two controlled stages the strip is usable with almost any tuner unit COLOUR TELEVISION Two features next month on colour television First a detailed look
306. z The Great Voice of the Great Lakes in Detroit WBBM 780 WLS 890 WCFL 1000 in Chicago WHO Des Moines Iowa on 1040 KMOX 1120 The Voice of St Louis WOAI 1200 San Antonio Texas By the end of the month reception of the West Coast becomes possible from 0400 hrs GMT until sunrise This is a favour able time of year for the West Coast since European QRM is light just before dawn while locals have not yet signed on Last year the following stations were logged during the first week in September KOMO 1000kHz and KING 1090kHz both in Seattle KNX 1070 Los Angeles KFBK 1530 Sacramento Cali fornia Others that might be heard are KSL 1160 in Salt Lake City Utah and KEX 1190 in Portland Oregon The recent interest in Vintage Radio brings to mind that early broadcast receivers operated mainly on the medium and long waves Many of them could pull in DX from North America for in the mid twenties it was not unusual to read of reception of stations such as WGY Schenectady N Y on 380 metres by DXers using straight receivers and indoor aerials The state of the MW band was more favourable for DX then as there was little QRM while transmitters used flat topped aerials which radiate lots of sky wave Vintage receivers would hardly be successful on the medium waves today though it would be intriguing to try one out but many of the early stations are still broadcasting and are often logged by the DXer WGY is cur rently on 810kHz it
307. zing Radio Constructlon set radio Become a The remarkable quality and performance of the Major makes possible truly brilliant and rich sound from a single loudspeaker It recreates the entire musical spectrum from 30 to 14 500 c p s The unit consists of the latest double cone woofer and tweeter cone together with a special Baker CERAMIC mag net assembly having a flux density of 14 000 gauss and a total flux of 145 000 Maxwells Bass resonance 45 c p s For Hi Fi or PLA Rated 20 watts Voice coils available 3 or 8 or 15 ohms Maior Module 30 17 000 cps with tweeter crossover baffle 19 4 123in and instructions l 10 0 SHORTWAVE TRANSISTOR RADIO can be buit 45 in one evening onis At last After trying enunt leas circuits searching for easy build work first time short waver we 2x expert for 39 6 chose this Sky A complete Home Roma Any Radio Course No one from 9 cluding DA Z 204 Transistors etc all you need Box size 14 x 10 x parts avail sep amp P Money back guarantee experience needed Parta in in structions for cach design Btep by step plan all loud speaker personal phone knobs screws D L4 Bend only 89 68 4 6 years up can p lullow the step by ZR vasyras ABU fully illustrated instruc tions No soldering necessary 76 stations logged on rod aerial in 30 minutes Russia Africa U S A etc Experie

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