"service manual"
Contents
1. 7rteast net Copyright c 2002 2007 by Harold Melton KV5R All Rights Reserved l May not be copied without express written permission Feel free to link to wae this page W3 http www athensarc org 706 asp 2007 10 282. a AAN N LAA A J AA r FIAN ecm tiie g f x Ba a q i wes VA MA NW i wN Yy m INNIN A iad i XZ I wv a NOTE The author does NOT advocate any illegal operation It iS i YOUR responsibility to stay within your authorized bands NOTE This is for the MkIIG ONLY Earlier models use an entirely different procedure NOTE This procedure WILL RESET the radio to a factory new a a condition All memories and settings will be cleared This modification a w will allow the MkIIG to transmit on most of the frequencies t that it receives on It is useful for 1 Accessing the oy id aus O new Amateur saw 60 meter m TA channels E ki E 2 Authorized pa T it E a E a ke y y gt MARS and or J1 Fig a a WA LA CAP operation Mh L a ed http www athensarc org 706 asp 2007 10 28 Icom 706 Mk2G Page and Homebrew Projects Sida 15 av 28 Authorized Maritime and or Aviation SSB operation Authorized VHF and UHF public service police fire etc operation Authorized Land Mobile radio operation Authorized VHF marine operation ee E Unauthorized operation on any frequency only in immanent life death emergency only when no other means of communication are possible legal but still legally risky 8 NOTE Amateur Radios are NOT FCC TYPE ACCEPTED to operate in other services even if you have the license to do so Don t goof around in the legal gray area unless your leg is m
3. you can beat their 600Hz audio against that Still another way is to tune 600 Hz low USB listen and switch to 600 Hz high LSB and compare the tones When they are equal you re exact Yet another way is use the CW Reverse feature Tune 10 000 000 then push CW You ll hear the offest beat as it shifts the radio 600 Hz Now push and hold Mode to switch to CW R and compare the tone Continues switching between CW and CW R and adjusting the 10 MHz oscillator of the LF converter until the tones equalize Noise Bridge Tuner Tuner Here s yet another case of buy for 100 or build for 20 Dave Benson http www athensarc org 706 asp 2007 10 28 Icom 706 Mk2G Page and Homebrew Projects Sida 24 av 28 KISWL of Small Wonder Labs sent me this neato noise bridge circuit put it in a little box and added battery switches and connectors The PCB and its parts were 17 delivered My box isn t very pretty but it works great use it to tune up the antenna tuner on 60 where it s not legal to transmit dead carrier What it does A noise bridge makes broadband noise and feeds it through a bridge circuit to a receiver It is first calibrated to a known desired resistance say 50 ohms then the unknown load is connected Now it starts to get interesting By tuning the receiver and listening for the null you can determine the resonant or notch frequency of various tuned circuits like traps antennas or even antenna tuners without transmit
4. You have now adjusted the tuner so that it looks like a 50 ohm resistance with no reactance i e exactly what your radio wants to see 10 Turn OFF and BYPASS the bridge 11 Transmit with low power and fine tune the settings on the antenna tuner if necessary Pros and Cons 1 After some practice you ll find that tuning the tuner by ear is much faster and more intuitive than watching SWR needles You may even discover more tuner combinations with better wider Q as did on several bands 2 The Q of the bridge isn t very high That means it s fairly easy to calibrate but doesn t give a very sharp null 3 It works much better on 20 meters and above than on 17 and below On 80 meters you can ballpark it but may still have to transmit to fine tune the tuner 4 This bridge has it s pot and trimmer on the pcb Converting to external ones with big pointer knobs would allow it to be scaled to show resistance and reactance As is the unit is more than sufficient to allow one to ballpark his tuner traps and driven elements without the high expense of antenna analyzers It s well worth the 24 have in it and replaces units costing four times as much Thanks Dave CW Key Base Lightweight keys and paddles may be great for backbacking but what if all you want is the darn thing to stay reasonably still on the desk Make a base as wide as desired and about nine inches long Put some tacky non slip rubberized mate
5. 28 Icom 706 Mk2G Page and Homebrew Projects Sida 19 av 28 Note You do not really need a fancy expensive crimping tool to install the modular plug Simply clamp the plug in a hobby vise with the catch down and drive each pin with a medium sized jeweler s screwdriver Make sure they are all fully seated use your 3 5 xX magnifier The cable crimp may be pressed down and locked with a large screwdriver If you don t want to tackle this just get a computer network patch cable and chop it in half decided to use the CueCat s cord because it s small and soft and it has one shielded lead Refer to your Icom manual for mic plug wiring Make sure to use the cord s Shield wire as the mic ground to prevent RF pickup It s a snug fit melt away unnecessary plastic in the base plate until it fits Double the cord around put a cable tie on it and run it out the tail hole Finally A useful CueCat Mark the bottom as to which jack is which Mic Preamp Text and schematic by Anthony Gargasz KBBWOW This nifty little audio preamp can be used for just about anything you can dream up from microphones QRP rigs even guitars An emitter resistor value of 390 ohms works well in most cases All resistors should be 1 8 watt 5 tolerance Regular carbon composition types are OK Use metal film types if you require ultra low noise operation The emitter bypass capacitor can be eliminated for low source impedance devices such as dynamic micr
6. alternate 599 9 600 0 in AM mode and then your computer will also be calibrated 5 When satisfied replace the cover and return the room to normal temperature Testing the Frequency Calibration Notes 1 Accuracy increases on lower frequencies and decreases on higher frequencies For example if it is off 1 Hz at 20 MHz it will be off 0 5 at 10 or 0 25 at 5 or 10 Hz at 200 MHz and 20 at 400 Hence Icon Service and the Service Manual will tell you to calibrate the radio using a lab grade Service Monitor or Frequency Counter at 60 MHz or higher However even the best lab grade equipment is calibrated to WWV the National Atomic Time and Frequency Standard so recommend just bypassing the Service Monitor and using WWV directly at its highest frequency 20 MHz and getting the Master Oscillator within 1 Hz in a temperature stabilized room 2 Many do not know that the modulated audio tones on WWV are also Frequency Reference Standards The beep at the top of each minute is exactly 1000 Hz the continuous tones when on alternate between 500 and 600 Thus you can listen to WWV on AM and get an exact 500 or 600 Hz tone then switch to LSB and USB and compare them with the true tone heard on AM You can also beat a 500 or 600 Hz offset tone against the 500 or 600 Hz modulation when available but this beat is hard to hear below a few Hz 3 To periodically test the calibration simply return to 15 or 20 MHz exactly and rep
7. and adjust the lighting Get the jeweler s screwdriver that precisely fits the slot in the trimmer Capacitor Wrap a band of electrical tape around the handle of the screwdriver until is it 1 2 to 3 4 inch in diameter This allows you much more precise control NOTE Touch the tiny components with the lightest possible pressure Set the VR to Its mid point Adjust the trimmer cap as close as possible coarse adjustment Use the lightest possible touch Remember to remove the screwdriver from the trimmer cap when comparing CW CW R tones DO NOT adjust any of the coils L623 or L601 Finally adjust the VR fine adjustment until you hear no frequency shift between CW and CW R High Precision Adjustment L 2 http www athensarc org 706 asp Connect the radio s audio output to the audio line in of a computer set the volume low Run a program such as MixW that has a continuously averaging audio frequency display in the status line Repeatedly adjust the VR very carefully until no frequency shift is seen on the computer It is possible to get within 1 Hz Note Your computer soundcard clock may not be calibrated so you may not see 600 0 Hz on the status line frequency readout Simply adjust the VR until the numbers are equalized between CW and CW R modes Afterward you can adjust your soundcard clock in MixW to make it Sida 5 av 28 2007 10 28 Icom 706 Mk2G Page and Homebrew Projects Sida 6 av 28
8. jacks The buss wire is 14 The box is from an old laptop computer power supply It has a steel body and a plastic top perfect for this application http www athensarc org 706 asp 2007 10 28 Icom 706 Mk2G Page and Homebrew Projects Sida 21 av 28 LF Converter LF Convert always wanted to check out the basement that s what the LF crowd calls the frequency spectrum below 300kKHz One of the things that attracted me to the 706 was the claimed specification of 30kHz But alas the 706 s sensitivity in the basement is in the toilet the radio is nearly useless below about 400KHz So poked around online and learned that what needed was an LF converter a simple IF oscillator mixer that you add between the radio and the antenna Palomar makes a nice one 100 far too much nice for my wallet More searching yielded this little kit from Jackson Harbor Press WB9KZY which comes delivered for 12 Now that s more like it The kit includes the PCB and http www athensarc org 706 asp 2007 10 28 Icom 706 Mk2G Page and Homebrew Projects Sida 22 av 28 all components except case and jacks Also you have to download the assembly manual online You can visit them and read about it and order it here The kit s PCB takes under an hour to assemble and it you re like me 4 5 more hours to get it installed in a box F re ih ai a The kit is on two boards they may be soldered together Mount ever
9. keep the signal level fairly low when running digital modes 4 4 When running PSK at 1000 Hz with a strong signal an harmonic image can be seen barely at 2000 Hz It s not a problem at all it may be generated in my computer not the radio http www athensarc org 706 asp 2007 10 28 Icom 706 Mk2G Page and Homebrew Projects How to use 1 Run setup Lock Power and select FL 223 for the slot in which the FL 232 is installed That will make the radio think it s a 223 a narrow SSB filter so that you can then select it while in SSB For the usual computer soundcard digital modes PSK FSK MFSK etc set USB start with no filter set the signal at 1000 Hz select the narrow filter Fil N and crank the IF shift all the way right and that ll center it at 1000 Hz in USB Or simply leave the IF centered filter at 2150 and then tune your desired signals there However if you set your PSK software to copy at 2150 it will also transmit at 2150 and this may confuse other users who are accustomed to using 1000 Hz only When a strong signal overloads your receiver just shift the IF until your desired weak signal is right on the edge and the filter will wipe out the nearby strong signal If the offending signal is splattering complain Micorphone Tips Sida 17 av 28 Note The supplied HM 103 hand mike is the best one you can run on the 706 do NOT recommend using other mikes on the 706 except the Heil iCM serie
10. on the digital modes at www athensarc org digital modes asp The rest of the initial settings are usually OK by preference or as needed Now power off and on and go to the Q menu by holding in the Display button Set the mike gain to 4 5 i e just where it changes from a 4 toa 5 Notes 1 The supplied HM 103 hand mike contains a 1 inch broadcast type condenser element designed by Bob Heil for Icon and has excellent quality better than most HF radios Never talk flat into the mike talk across it about an inch away This large diaphragm mike element is too sensitive to use flat against the mouth The HM 103 hand mike and the Heil iCM series are the only mikes you should use with a 706 Do not attach other mikes to the 706 or you will be disappointed 2 The mike gain setting is the same for all bands and modes Mike settings are NOT stored by band modes nor memory channel 3 Setting the mike gain at 4 5 and talking across it is sufficient for all bands and modes 4 Do not use the processor CMP except in extremely marginal conditions The supplied hand mike is so clear that the added punch of the processor is rarely needed Also the processor will add substantial bandwidth and splatter on SSB drawing complaints form nearby QSOs 5 The output power level is NOT stored in memories There is one setting for HF and one for V UHF Output power will need to be adjusted manually as you move from nearby to distant repea
11. schematic in Shacks with low RF density Rx should probably be 600 ohms to match mic input of radio My first interface does not include CI V Tune Control Activator The 706 has circuitry built in to control an automatic antenna tuner This is activated by the Tune Call button If there is no tuner connected the button does nothing If one is detected pressing the Tune button causes the radio to switch CW and transmit carrier at 10 watts This functionality is also useful for those who use a manual tuner but to use it we must make the 706 think that it has an antenna tuner connected Commercially made tune control modules are available for 30 We can build one for 3 The following circuit by G4FZN activates the tune control Pressing the Tune button once turns carrier on pressing again turns it off If you don t turn it off this circuit will time it out in about 10 seconds If the circuit times out the http www athensarc org 706 asp 2007 10 28 Icom 706 Mk2G Page and Homebrew Projects Sida 13 av 28 carrier goes off but the Tune function stays on red LED lit ont he Tune button Press the Tune button twice quickly to turn Tune function off If you leave Tune function on the radio will emit carrier anytime it thinks it needs to retune the autotuner such as when you switch bands or when it detects high SWR Therefore when using a Tune Control Activator not a real autotuner you always want to turn Tune mode
12. 2G Page and Homebrew Projects Sida 16 av 28 The removed diode The rod is a 0 5 millimeter mechanical pencil lead You can see the diode is about 3 4 x 1 millimeter Filters If you run CW or narrowband digital modes like PSK 31 you need a narrow filter recommend the FL 232 350Hz CW RITTY filter It is available from all Icom dealers Look for the best price online have seen them as low as 79 95 Universal Radio and HRO sold me one for the rock bottom price of 78 Many vendors sell them for 95 105 Don t pay too much Pop the filter in then go into setup and tell the radio it s an FL 223 not 232 This will allow you to select the filter in SSB mode as well as CW and RTTY This will allow you to select Narrow on SSB and have about a 450Hz wide bandwidth on your waterfall How it acts 1 1 In CW and CW Reverse it acts as expected setting itself at 600 Hz The IF shift will move it around about 600 Hz 2 2 In SSB it ll act like a RTTY filter In USB it centers at about 2150 Hz The IF shift will pull it down to about 1000 Hz for PSK use But in LSB it positions itself low The IF shift will move it down through zero to the other sideband or up to about 2k 3 3 Though called a 350 Hz filter 6db my waterfall shows it to be about 500 Hz wide on moderate signals Kicking in the attenuator or rolling down the RF gain will narrow it just a bit As with all narrow filters it works best when lightly loaded so
13. Icom 706 Mk2G Page and Homebrew Projects Home Technical I ndex Site Map i pm Nets Tra m Ners Sida 1 av 28 ffic Scouts Photo Index Roster Repeaters Zm Nets AF Nets KV5R s Icom IC 706MkKIITG Mods and Tips Page KV5R Web Designs Web Designer Developer kv5r at kv5r dot com can build you a real nice Ham radio web site or do an extreme makeover on your existing site KV5R com Rockwall Community Church Bee Line USA Lake Palestine Chamber of Commerce Advantage Homes Athens ARC Texas Traffic Net Lake Athens Baptist Church Dan Taylor amp Associates East Texas Cable Southwest Traffic Net Introduction Ads by Google Handheld 802 11BANG Wi Fi 2 4 5GHz Spectrum Packet Analysis 802 11n 802 11b g 802 11a Analysis www bvsystems com CW McCall Fa CW McCall Ringsignaler for Mobilen Skynda Dig Ladda Ringsignaler com Fix cw exe Download a Free Scan Tool amp Fix cw exe Instantly www TuneupAdvisor com ATC Radios Install antennas without coax ATC antennas up to 10km away www syntonicsCorp com c 2003 2006 by Harold Melton KV5R All Rights Reserved Rev 06 11 05 Everything for 706 Lovers in One Place Page Index Brand New Setup Frequency Calibration Locating Computer Interface Tune Control Frequency Expansion Filters Microphone Preamp Headset Adapter Hand Footswitch DC Buss LF Converter Noise Bridge Key Bas
14. ashed under an 11 ton boulder Remember that other non Amateur radio services require not only a license but also a radio that is FCC Type Accepted for that service Tools The 706 uses components that are extremely tiny You will need at least the following tools 1 2 5x to 3 5x headband visor magnifier or jeweler s loupe 2 Bright light 3 15 watt pencil iron with a clean lightly tinned needle sharp point 4 Fine point tweezers 5 Extremely steady hand How to remove it D2030 1C 706MkIIG ONLY Top PCB Red Arrow Indicates tiny SMT Diode to Remove 1 Some people just crush it with needle nose don t like that idea since it might damage the PCB 2 Take the tip out of your 15 watt tron Chuck it in a drill Turn it against a grinding stone to a needle point 3 Reinstall the tip Heat and re tin it Tap off the excess solder 4 Remove power cable from radio Remove top cover slowly Carefully unplug speaker 5 Using visor magnifier and bright light and a very steady hand catch one end of the diode with tip of iron very lightly tinned 6 Gently pull upward with the iron The diode will either rotate upward on it s other lead or it ll break off 7 If you lift one end just a little you can leave the diode there in case it ever needs to be reattached 8 Plug in speaker Reinstall cover Power up Reprogram all your memories and settings http www athensarc org 706 asp 2007 10 28 Icom 706 Mk
15. aults Go to Initial Set Mode by power off hold Lock button and power on Refer to the initial setup items on pages 50 55 Item 1 You can turn off modes that you don t want the Mode button to select in its rotation Unless you have an external FSK RTTY system connected turn off RTTY mode Most of us on RTTY are now operating AFSK RTTY via a computer where you ll be running on SSB Items 2 and 3 When you get tired of hearing it beep turn beeps off Items 4 and 5 When operating the radio in the house Low lighting is sufficient Daytime mobile operation will benefit from High lighting of the display Item 7 RF SQL This requires some explanation Set to RF SQL the knob will act as RF gain from 7 12 O clock and Squelch from 12 7 O clock Set item 7 to RF SQL and set the knob to about 12 30 and you ll never have to mess with it again If set to Auto you ll have to crank it around every time you switch from SSB CW to FM modes The RF SQL setting is the most convenient Item 8 Sub dial Set it to RIT tf you operate HF This makes the Memory Channel knob operate as a RIT while in VFO A B modes Regardless of where you set this setting the knob will still operate as Memory Channel while in the MEMOry mode Items 9 and 10 Optional Filters Set to No tf you have not purchased optional filters If you add one filter recommend the FL 232 in slot 1 and set the Opt Fil 1 setting to FL 223 This will 1 give you an effective CW fi
16. da 9 av 28 _ eo a ee tea EEN m i s y i fi ee Left Another idea for control head placement Right The radio and major bird nest is located under the desk out of the way Power supply and computer interface under there too Mounting rear down enhances cooling and prevents cable strain Also it s less than 3 feet from the ground rod Computer Control and Soundcard Interface Interfacing the radio to your PC has too many way cool advantages Computer enhanced radio control and programming automated logging and a multitude of digital soundcard modes See my Getting Started in PC Soundcard Digital Modes page The 706 has the usual 1 8th inch Cl V remote control jack To connect to a computer you must purchase the Icon interface for 140 and a soundcard http www athensarc org 706 asp 2007 10 28 Icom 706 Mk2G Page and Homebrew Projects interface for 100 OR NOT This circuit will cost perhaps 25 with case and cables and plugs and does all these neat things 1 Cl V to RS 232 data interface for radio computer control 2 RTS to PTT switching 3 DTR to CW Key switching 4 Audio to from computer soundcard not shown in schematic Notes 1 No one but you are responsible for mistakes damage This circuit if improperly built or connected could damage your radio and or your computer Work carefully Double check everything All can say is mine works fine no guarantee yours will 2 Cho
17. e Links How to connect a 706 to an SGC PDF How to connect a 06 to an amp Web Page or PDF file by K6XX Ah the li l 706 What can say like it It performs like big radio but it s small It sounds good and it s well made You can add the remote kit and put http www athensarc org 706 asp 2007 10 28 Icom 706 Mk2G Page and Homebrew Projects Sida 2 av 28 the control head and the radio box where ever you want them The price is right This article is a handy compilation of most of the mods and stuff have developed or found on the web for the 7O6MkIIG plus a chronicle of the little accessory kits that have built to enhance my enjoyment of the 706 Disclaimer The author assumes absolutely no responsibility under any circumstances for what the reader may do with this information Building and connecting circuits and performing adjustments or modifications may damage your radio void your warranty and or cause it to operate in violation of FCC rules and Type Acceptance etc unless you are VERY CAREFUL Notice This page contains several schematics and kits designed by others They are fully credited and make no claims upon them by copyrighting this page Such copyright only applies to my original writing and photos Brand New 706 Setup The 706 comes with some power on factory defaults that you will want to change The recommended changes make the radio easier to operate First let s set up the power on def
18. eatedly switch between CW and CW R comparing the tones You ll see it go off a little when the room temperature is not normal and when the radio is heated up from lots of transmitting but it shouldn t be more than 2 3 Hz off at 20 MHz 4 You can determine your exact error by connecting to a computer and reading the frequency differential between CW and CW R Divide the differential by two and that will be your error readable to within 0 01 Hz using MixW If you then QSY down divide the new frequency by the old to get the ratio then divide the error by that Using this technique was able to win the 2004 ARRL FMT award certificate by getting within 0 04 Hz 5 You can determine the frequency error of other people s radios Have them set to some exact reading and transmit a carrier for 10 seconds or so Switch your mode to CW and alternate between CW and CW R while adjusting your VFO to equalize the tones set tuning step TS to 1 Hz resolution Compare your readout with theirs The differential will be their radio s display error plus or minus your own error which is hopefully within 1 Hz referenced to WWV have observed that a high percentage of Hams are running an error of 40 60 Hz This may be acceptable on older pre PLL radios but modern radios with PLL and a Master Oscillator can be calibrated much closer Also have also observed that new factory fresh radios are typically off up to 50 Hz This may not sound like
19. llips screwdriver 2 Jeweler s Screwdriver set 3 3 5 X headband magnifier and a bright light 4 Air Conditioner and or heater and digital thermometer to control room temperature 5 And for greatest precision a computer running MixW in the PSK mode read the audio frequency on the status line with 0 1 Hz resolution Not Necessary Oscilloscope Service Monitor or Frequency Counter thank goodness http www athensarc org 706 asp 2007 10 28 Icom 706 Mk2G Page and Homebrew Projects Procedure L a oe a E 10 11 12 I3 14 L5 16 17 18 19 20 Measure your normal room temperature The radio inside runs about 10 degrees F above ambient while closed and receiving Increase your room temperature 10 degrees above normal and stabilize it Lay the radio upside down on a pad front facing you Connect power and antenna Remove the bottom cover and set it aside Verify the room temperature is 10 degrees above normal and stable Turn the radio on and let it receive for 30 minutes or so Set and lock the VFO to the highest WWV signal you can hear usually 20 000 000 Hz Set Mode to CW You will hear the 600 Hz receiver offset tone beating the WWV carrier Press and hold 1 second the Mode button repeatedly switching between CW and CW Reverse Compare the two tones If there is any shift in the CW and CW R tones you need to calibrate the Master Oscillator Don the magnifier
20. lter and 2 let you select N narrow while on SSB giving you the 350 Hz filter for digital modes like PSK 31 Installing the 232 but selecting the 223 fools the radio so you can use it on SSB See the Section below on Filters Item 20 Auto Repeater This should definitely be changed from the default Set it to On 2 and the 2 meter band will automatically set the right offset when you are in the range of the usual repeater bands 600 negative below 147 and 600 positive when above 147 This will save you a lot of extra offset setting while you are programming your repeater channels Also sets the usual 5 00 http www athensarc org 706 asp 2007 10 28 Icom 706 Mk2G Page and Homebrew Projects Sida 3 av 28 MHz offset for 440 repeaters Item 24 AM NB Set to off and the Noise Blanker will be disabled on AM reception where it will otherwise cause distortion to strong AM signals Item 30 VSend Sel Set to off the HSend line on the Acc y jack will key the radio on all bands Set to on the default HSend will key the radio on HF 6 while VSend will key it on V UHF bands Off is useful if you will key the radio from a computer interface for all bands On is useful of you will key the radio with a computer on HF but with an external TNC for V UHF You ll need to study the book and do some fancy wiring on the 13 pin DIN plug To operate the computer digital modes see the interface section below as well as my big article
21. much but remember tf you re off 50 Hz on 40 meters you ll be off a whopping 1 kHz on 2 meters and 3 kHz on 440 not acceptable Since you have the time you can do much better than the factory http www athensarc org 706 asp 2007 10 28 Icom 706 Mk2G Page and Homebrew Projects Sida 7 av 28 Locating the Giblets The best thing about the 706 is being able to put the control head where you want and need it This is not only handy in mobile installations but at home as well In my case it s essential as illness forces me to stay in bed most of the time The head s by the bed and the shack s in the back Since live in a 30 foot trailer my station must be small just 2 shelves The radio and power supply are mounted below the lower shelf Not shown MFJ 949E replaced with MF 993 IntelliTuner Note the crystal radio on the left and the 25 1300 MHz scanner on the right http www athensarc org 706 asp 2007 10 28 Icom 706 Mk2G Page and Homebrew Projects Sida 8 av 28 ae ge eee ELEn Le r p GN i zm First position The control head was mounted on coffee table beside bed The 9 inch high mount is a PanaVise cell phone mount ai r l Epir Ta j ais JADEN i F Ie atthe mye a My latest bedside operating desk Middle shelf slides out for use 706 head mounted underneath top shelf on PanaVise cell phone mount http www athensarc org 706 asp 2007 10 28 Icom 706 Mk2G Page and Homebrew Projects Si
22. off Notes 1 You can lay the circuit out about like the schematic 2 C1 sets the timeout time 100uf 10 sec 50uf 6 sec 33uf 4 sec appx used 33uf Make sure it s 16v or more 3 You can buy the 4 pin Molex or just make your own pins See photo My pins are 12AWG wire Round on both ends with bench grinder then emory cloth Progressively mash with Vice Grips until they fit snugly into the radio s female connector Solder to wires Add heat shrink tubing Make sure you get them plugged in correctly 4 Wrap tape around the PCB plug it in and let it dangle 5 The 30 commercial units are much more tidy having a little plastic case that s molded onto a Molex plug Here is the easy one afternoon circuit NOTE As always no one but you are responsible for mistakes damage G4FZH IC 06 AUTOTUNE UNIT BY G3VFP TKEY TSTR 12 GND R4 E TKEY u al TSTR 12V Q1 GND S DEERE R1 10K 01 02 2H2222 OR COMMON HFH Re 22K D1 1N4146 R3 220K C1l 100MFD R4 47K R5 100K PRESSING THE TUNER CALL BUTTON WILL Ro 15K GIVE 10 SECS OF 10W OUTPUT Own Risk http www athensarc org 706 asp 2007 10 28 Icom 706 Mk2G Page and Homebrew Projects Sida 14 av 28 g My tune activator You can make a Molex by grinding one corner off of a computer power supply plug 2005 Update no longer use the Tune Control Activator because now use the MFJ 993 IntelliTuner I m very happy with it
23. off switch is useful when running SSTV where you need to talk then transmit SSTV 4 Obtain a quality electret condenser mic assembly designed for 8 volts DC phantom power A setreo mike element used on cam corders may be wired in parallel and you ll get lots of output that s needed by the pre Pro Icom radios These will not sound as good as the stock hand mike 5 Bob Heil will not sell you a bare iCM element even if you beg Headset Adapter Everybody got one because they were free The CueCat barcode scanner was fun for a few minutes but then what kept mine knowing that j somehow someday it just might be useful This project fills the need for a 706 mic headphone PTT adapter The guts of the Cat are discarded A large sturdy momentary pushbutton and two 1 8th inch jacks are installed iN his hindquarters The keyboard plug is chopped and replaced with an eight pin modular plug The adapter will then provide the ability to use any common electret headset with the 706 The PTT button may be used in the hand on the desk or on the floor as a footswitch Also it makes it easy to connect a tape recorder or other audio equipment to the 706 Operation You ll need to enable compression and increase the mic gain to accomodate most headset electret mics Inexpensive computer headsets will work but the audio quality will be substantially inferior to the stock mic http www athensarc org 706 asp 2007 10
24. ophones and guitar pickups High impedance devices such as crystal and electric condenser mics will require the capacitor Although a 10 mfd electrolytic is a good starting value you may use up to 100 mfd to get maximum AC gain Be judicious however too much gain in a single Stage invites hum and oscillation instabilities The capacitor should have a 35 VDC rating Want to experiment with the frequency response For low impedance sources try reducing the value of the input capacitor not past 0 01 for more treble Increasing the output capacitor up to 4 7 mfd will boost the bass There is allot of gain interaction when you change the capacitor values so be prepared for some trade offs Construction is not critical perf board works great There is only one rule of http www athensarc org 706 asp 2007 10 28 Icom 706 Mk2G Page and Homebrew Projects Sida 20 av 28 thumb keep all component leads that attach to the transistor as short as possible LOW SIGNAL NOISE HIGH AC GAIN PREAMP r 7016 YOC 2N5058 SIGMAL OUTPUT sok lt 330 TO 680 ADJUST FOR 12 SUPPLY VOLTAGE QUIESCENCE AT COLLECTOR WITH INPUT SOURCE IMPEDANCE CONNECTED DC Buss Box Like so many other things in ham radio you can spend 50 100 for it or make it yourself for less than 10 This DC buss distribution box uses two sets of 30 amp banana jacks and four sets of 15 amp banana jacks The feed wire is 10 stranded soldered between the 30 amp
25. p www athensarc org 706 asp Computer side cables Radio side cables 5 conductors to RS 232 9 5 conductors to 13 pin ACC se ary plug Ground to pin 2 red Pin 3 DTX PTT to pin 3 orange Pin 5 Gnd eo pins ey Pin 7 RTS A black box with PCB MOD in to pin 11 pink Pin 4 DTR inside in the middle of a AF out to pin 12 light blue 6 foot assembly 2 conductors to 1 8th inch Cl Blue V plug 2 conductors to 1 4th inch KEY plug Sida 10 av 28 2007 10 28 Icom 706 Mk2G Page and Homebrew Projects Sida 11 av 28 Pink via 50k PCB pot o 13 86 From Rig cial et Ake Ale LO0R 2 3 gt 22 T m 2a a 23 5MM Mano Plug o 0 2 IN4148 a ra fo Sjo Screen Gnd u IN4148 e z 52 am IN4148 Eg 7 om Em o Ptt Line To ACC co OO oO CW keying line to rig C1 24 2M2222 or Similar npn CI V Interface with PTT and CW Keying by G3VFP Own Risk Audio Lines not Shown see below Building this circuit will save you over 150 eat i in t 3 7 dk F d B a _ pe i al ial a r oh Y iiy i Haa F om a Se _ My second interface includes CI V PTT KEY and Soundcard http www athensarc org 706 asp 2007 10 28 Icom 706 Mk2G Page and Homebrew Projects Sida 12 av 28 50k PC Line in Radio AF Out PC Line out DBJ pin 7 Ah Diodes 1N4145 Resistors 4r 00 OBS pin 5 2222 of SODA DBS pin 4 Ave If you don t want CI V interface use this simple non isolated
26. p a 6 foot serial RS 232 cable in half and use it for connections Ring out and document the appropriate RS 232 pins to wire colors Attach wires to PCB This saves having to solder the RS 232 plug 3 See page 6 of instruction manual Use the 13 pin DIN plug that comes with the radio 4 Get a Radio Shack 6 foot patch cord with stereo 1 8th inch mini jack on both ends Cut in half and use for audio lines from PCB to computer soundcard This saves having to solder the 1 8th inch plugs Tie both channels together or leave ring floating 5 Get a 2x3x5 plastic box Dremel grind mouse holes along top edge three per end for cables Put cable ties on cables Pinch them into mouse holes with lid This is much easier than running cables through drilled holes they will always be twisted Murphy 100 of the time before you get done 6 Make a cable with a 1 8th inch mono jack for the Cl V connection Make a cable with a 1 4th inch mono jack for the CW KEY connection 8 Dress all shielded cables at PCB connections with heat shrink avoid a lot 10 of shorts Dress both cable bundles with black plastic spiral wrap R S has it If you run QRO and or a lot of RF in the shack you ll probably need isolation transformers and perhaps ferrite chokes in the audio lines Try chokes first You ll end up with something line this 1 audio line to soundcard line in From ACC 12 Lt 1 audio line from soundcard speaker out To ACC 11 htt
27. po camera lens not the box had to grind about 1 4 inch off the PCB to get it in this tiny box east OKAY So a coat of white paint and computer printed labels would make it look nice was in a hurry To use as a tuner tuner First calibrate the bridge to 50 ohms resistive with no reactance 1 Connect it to your receiver set at 10 or 15 MHz or about mid range of were you plan to use it 2 Turn on inline 3 Connect it to the antenna tuner with a patch cable and always use same one thereafter 4 If the tuner has an internal dummy load select it on the Bypass side of the dial If not 5 Solder two 100 ohm precision resistors together in parallel and install them in a PL 259 Place this at the Antenna jack of your tuner 6 Adjust the trimmer cap and the pot very carefully for the best possible null in the noise When perfect you can turn the bridge power off on with no change in sound The bridge is now balanced to 50 ohms resistance and no reactance By placing the pure resistance at the antenna connector of the tuner you have balanced the bridge for both resistance and stray http www athensarc org 706 asp 2007 10 28 Icom 706 Mk2G Page and Homebrew Projects Sida 26 av 28 capacitance of the coax patch cable and the antenna tuner make sure the tuner is in bypass to the dummy load 7 Now remove the resistor and connect the Ant side to the antenna tuner 8 Adjust the tuner for the null 9
28. r Oscillator All other frequencies in the radio L O 3 4 I F stages VFO and CW offset are computer derived from the Master Oscillator This makes it relatively simple to frequency align the radio so that it agrees with the Frequency Display in all modes NOTE Various 706 models use different parts to calibrate the Master Oscillator Refer to your Instruction Manual Additionally the lower diagram on page 63 11 Internal Views in my Instruction Manual is wrong 1 In the position shown as R602 is a trimmer capacitor coarse adjustment and 2 Just above it is R602 the variable resistor fine adjustment and 3 Adjustment of L623 is not necessary It is possible if you are very careful to calibrate the radio to 1 Hz at 15 or 20 MHz WWV as reference Use the highest WWV frequency you can receive usually 20 MHz in the middle of the day Note This is not the procedure used by Icon and the Service Manual consider this procedure more accurate because it uses WWV directly bypassing the possible error of the Service Monitor which is supposedly calibrated to WWV This procedure only applies to radios without the optional TXCO high stability unit CR 282 Also this procedure is only for radios like mine having a trimmer cap and a VR nearly under the 60 MHz gray coax in the lower front right hand radio inverted corner These lie just to the right of the encased shielded master oscillator You will need 1 1 Phi
29. rial onthe bottom Between that and the weight of your hand it ll stay put the non slip material is available tn little rolls from R V dealers http www athensarc org 706 asp 2007 10 28 Icom 706 Mk2G Page and Homebrew Projects Sida 27 av 28 Mount one or more keys on a piece of Melamine Glue R V shelf non slip pad to the bottom This material may gradually damage certain finishes Alas This is so much better Links to Other Great 706 Places Amateur Radio Technical Articles and Tables from KV5R Technical Index com America Amateur Radios IC 706MKIIG Main they made it http www rigpix com icom ic706mkiig_service pdf Download and print the official C 706MkIIG ServiceManual and Save 25 Shows you how and where to align and tweak everything advanced users only http www athensarc org 706 asp 2007 10 28 Icom 706 Mk2G Page and Homebrew Projects Sida 28 av 28 Google Search 7O6MkIIG OR 7O6Mk2G 2100 hits G3BVFP s Fantastic List of Schematics Circuits and Software too cool www mods dk Frames Click com then click IC 706Mkii then click view all mods then save it Yahoo Groups ic706 Messages Users discuss all the details eHam net Reviews ICOM IC 706 All flavors read what hundreds of users Say about It CI V Information pages by DF4OR Lots of Cl V radio control software Big list of radio control software from QRZ Broke add improve comment Email
30. s Other mikes including Icom desk mikes will have a sound clarity that is inferior to the stock hand mike yes really The HM 103 sounds best when you talk across it Never place it flat against the mouth as this will cause considerable distortion If you really want to connect another mic The 706 uses an 8 pin modular RJ connector for the microphone This is the same as used by CAT 5 computer LAN network cables The connector costs 4 each and requires a rather expensive assembly crimp tool My way is of course much better l 2 3 4 5 Go to office computer supply store Buy a nice soft CAT 5a LAN patch cable one with nice molded strain relief plugs Get a 10 footer Cut off one end or cut in half to make two mic cables Ring out and document pin numbers to wire colors Solder the conductors into your mic or other audio accessory You can find an old classic mike and replace the element in it with a modern http www athensarc org 706 asp 2007 10 28 Icom 706 Mk2G Page and Homebrew Projects Sida 18 av 28 electret condenser See photo ElectroVoice Mercury and Shure Unisphere A The Shure has been modified with a dual element electret PTT switch and CAT 5a cable don t use it because the sound quality is inferior to the stock mic Notes 1 Rewire the mic s on off switch for PTT 2 Wire the element always hot or you won t be able to use VOX 3 On the other hand a mic
31. ters or from strong to weak SSB Stations 6 Icon radios seem to use the ALC circuit to control power output When you are at high power you ll see little or no ALC meter Indication when at low power you will see full ALC indication This is normal operation Do NOT adjust the mike gain to set ALC levels as with most other radios Leave the mike gain at 4 5 set the power as needed and don t worry about the ALC meter 7 If you do install a different mike you ll need to determine a new best mike gain setting Setting up your memory channels It is important to set up your memory channels in a table before committing to fully programming the 706 recommend you 1 Group all your FM channels together from 50 99 or so http www athensarc org 706 asp 2007 10 28 Icom 706 Mk2G Page and Homebrew Projects Sida 4 av 28 2 Group all your other non FM channels together from 1 49 or so 3 Use a Word table to develop your channel list sort it by frequency then install it 4 Take your time The better your list the less fragmentation will develop over time 5 If you perform the Frequency Expansion modification below it will erase ALL settings and memories and return the radio to factory settings If you REALLY want to use 60 meters and or MARS do it NOW and save the long process of programming everything twice Frequency Calibration Unlike older radios the 706 uses only one crystal oscillator called the Maste
32. ting built mine primarily as a tuner tuner to use for Field Day so can tune the tuner without creating QRM or desensing the other radios in the Field Day operation It will also come in handy to prune my multiwire fan dipole Besides all that it s just plain neato because it s old fashioned cool useful and not everybody has one Has both banana jacks and coax connector Inside The NEQRP noise bridge circuit from Small Wonder Labs Bottom Power switch output to receiver and bypass switch CAUTION If you transmit into the noise bridge it might FRY it Always make sure the bypass switch is on Bypass before transmitting Notes 1 If you get a three pole double throw switch you can eliminate one switch 2 The bypass should handle at least a couple hundred watts 3 The chassis is ground for everything 4 The battery fit inside but it s so tight had to wrap it with tape attached the battery to the lid with a cable tie through two holes It s too tight a fit for a battery clip If you do this project use a little bit larger box http www athensarc org 706 asp 2007 10 28 Icom 706 Mk2G Page and Homebrew Projects Sida 25 av 28 5 Get the kind of banana jacks that will accept lugs tinned wires and banana test leads Handy 6 The board doesn t have any mounting holes squeezed one between R4 and R6 and another one at the extreme right edge see photo above Photo above The bulge is in the chea
33. ything as low as possible Lay down the larger caps The chip is the oscillator mixer The crystal is 10 MHz The tuning capacitor can set the oscillator to within 10 20 Hz beat it against WWV Power is 13 8 VDC the board contains an 8 volt regulator The toroids are part of the input low pass filter pm http www athensarc org 706 asp 2007 10 28 Icom 706 Mk2G Page and Homebrew Projects Sida 23 av 28 The bottom Operation Connect the LF converter to your radio Tune to 10 000 000 MHz and you ll hear the oscillator at about S9 60db Zero beat the oscillator Now connect the antenna and start tuning upwards Mostly you will hear the grinding of triacs SCRs and switch mode power supplies After fighting that mess for awhile you will want to build a nice shielded loop receiving antenna Search online for plans and interesting frequencies Warning If you key the radio you will fry the converter s output amp transistor and probably the chip too Disconnect the mic Don t hit that Tune button or CW key Note To zero beat most accurately tune the radio to 10 000 600 600 Hz high LSB then wait for a minute in which WWV is transmitting a 600 Hz audio tone the higher of the two they alternate between the lower is 500 Now you can beat your 600 Hz carrier offset against their 600 Hz tone which is a lot easier than trying to beat at zero where you can t hear it Another way is if your radio has a 600 Hz CW sidetone
Download Pdf Manuals
Related Search