PCARA Update March 2009
Contents
1. for Bob s re peater on 448 725 MHz with a 107 2 Hz PL tone This time I chose two diode arrays that had originally been programmed for a simplex transmit and receive fre quency of 463 925 MHz This needed a lot more diodes to be changed and it took a while to get all the connec tions soldered But after a few corrections the radio came up on the correct frequency Uniden AMU 250 after conversion to 440 MHz with new panel lamp in place As a finishing touch I decided to replace the panel lamp that illuminates the back of the channel indicator The type of bulb used is a small 12 volt pea lamp with wire leads I managed to find a suitable bulb at Radio Shack disguised as a red snap in 12 VDC Lamp Assembly part number 272 0332 Pulling the plastic assembly apart revealed a suitable wire ended bulb within Nostalgia time I must say that programming radios with a diode matrix like the Uniden s is not as easy as I remembered I must have been looking back at my past experiences with older radios through rose tinted spectacles If there was a need to change frequencies again or add more channels quite a lot of work is involved The 18 pin diode arrays are no longer available and the multi channel circuit boards are showing distinct signs of wear and tear I think this radio will be staying on our two local UHF repeaters for quite a while NM9J Quick Icom repair Completing the Uniden conversion gave me a2. removing a black rubber cover and straighten ing three metal clips the entire LCD assembly can be lifted straight off the circuit board revealing three green colored dial lamps DS1 DS2 and DS3 mounted directly on the Logic A circuit board After removing the LCD assembly the Logic A circuit board is visible with three green backlight lamps first one arrowed New Lamps for Old These lamps are specified in the Icom parts list as HRS 7219A G40 which is a 12 volt grain of wheat bulb with twin wire connections I found an equivalent at Radio Shack part number 272 1092 a 7219 Micro Lamp rated at 12 volts 60 milliamps with a wire terminal base The lamps on the Icom circuit board were covered with thin green silicone rubber caps The transparent caps change the display color from amber to green I transferred the rubber caps to the new bulbs cut the wire leads to the old bulbs then soldered the new bulbs in their place on the circuit board Positioning of the new bulbs is critical because they have to fit into three cutouts in the plastic light guide that surrounds the LCD assembly Refitting the LCD assembly and powering up the radio proved that the new lamps were now lit and the liquid crystal display was still functioning correctly The front panel was reas sembled then the top and bottom covers were replaced The radio was as good as new In these times of economic uncertainty it is well wo
3. 0 a m Contact D Calabrese 914 667 0587 Mar 12 WECA Westchester Cnty Fire Trg Center 4 Dana Rd Valhalla NY 7 00 p m Contact Stanley Rothman 914 831 3258 Mar 16 Columbia Univ VE Team 2960 Broadway 115 Havemeyer Hall New York NY 6 30 p m Contact Alan Croswell 212 854 3754 Mar 20 Bergen ARA Westwood Regional HS 701 Ridgewood Rd Washington Twnshp NJ 7 00 p m Contact Donald C Younger 201 265 6583 Mar 28 Orange County ARC Town of Wallkill Community Center 2 Wes Warren Rd Middletown NY 8 30 a m Apr 25 PEARL Mahopac Public Library 668 Rt 6 Mahopac NY 10 00 a m Contact NM9J A Peekskill Cortlandt Amateur Radio Association Inc AT PO Box 146 Crompond NY 10517 PCARA Update March 2009 page 8
4. Y PCARA Update Volume 10 Issue 3 Peekskill Cortlandt Amateur Radio Association Inc March 2009 Consider conversion Ever wonder what happens to old commercial grade radio equipment Something that was state of the art at one time becomes available for a fraction of its original cost on line or at hamfests At our April 5 meeting Bob N2CBH will be demonstrating how to re purpose rock bound legacy commercial gear for ama teur use Bob will show us how to convert VHF Hi and UHF HTs to amateur service through the use of new crystals and a couple of tweaks This could be devel oped into a club project of modifying a bunch of surplus commercial HTs and mobile radios to amateur use for emergency preparedness Let s talk PCARA has taken a club table at the Orange County Amateur Radio Club Hamfest on Saturday March 28 2009 at the Town of Wallkill Community Center in Middletown NY For further details visit the OCARC website at http www ocarc ny org Take this opportunity to get a jump on your shack s Spring cleaning Make room for all the new gear you ll be getting as a result of the windfall from the 2009 Eco nomic Stimulus Package Bring along any stuff that you re interested in selling and put it on the club table i Bob N2CBH Joe WA2MCR and Ray W2CH in conversation at the club table during the 2008 OCARC Hamfest If you manage to sell some of your stuff all we ask is that you consi
5. chance to repair my trusty old Icom IC 3200A trans ceiver This Icom was my first mobile radio purchased in the U S A costing 479 back in March 1986 This large sum bought a 25 watt 2 meter 440 MHz one band at a time transceiver with 10 memory channels At the time Icom radios stood out from the competition because they included the PL encode unit This was an optional extra for other manufacturers The radio was mounted in two different vehicles over a period of thirteen years after which it saw service indoors for monitoring the local UHF repeaters The LCD panel was backlit with three incandescent lamps and over a period of years these lamps failed one by one The third lamp burned out a few weeks ago leaving the LCD panel completely black The panel could be read in day light but at night I had to shine a flash light to check the frequency My first try at disassembling the front panel to reach the lamps was not encouraging After removing the top and bottom covers from the radio it was clear that behind the front panel were two circuit boards Logic A and Logic B with a large collection of multi way cables connecting the top Logic B board to the main transceiver body The Logic B board also held a lithium coin cell that backed up the CPU memory Disconnecting this battery would likely wipe out all the memories I put the radio back together again while I considered the problem for a few more weeks Befo
6. d by holding down a button and waiting for the correct prompt to be heard through your headphones in a sequence I found myself often turning the rig on and off just to get back to the default frequencies or state of operation The ATS II is obviously geared for advanced CW operators with a flair for the outdoors It is reminiscent of Dave Benson s Small Wonder Labs series of rigs but marketed and packaged in an entirely different way As a more casual operator I prefer Dave s SWL series but you certainly have to admire Steve s compact and light design The ATS II has now been refined with an entirely new model Check out all of Steve s work at http kd1jv qrpradio com Until next month best of 73s and dit dit de N2KZ The Old Goat PCARA Update March 2009 page 3 Uniden conversion A real bargain This story begins with the PCARA bring and buy auction in January Bob N2CBH had brought a bunch of commercial radiotelephone equipment to the auction and I was attracted to a Uniden UHF transceiver A little online research revealed that Bob s AMU 250 was a 25 watt mobile transceiver covering the commercial UHF band of 450 470 MHz Next time I met Bob the radio changed hands for a very reasonable sum Uniden AMU 250 UHF FM transceiver as received from Bob N2CBH Questions of conversion The obvious course of action was to convert the Uniden down to the 440 450 MHz amateur FM band Fortunately Bob had hande
7. d over a collection of documents related to the radio including the Uniden Service Manual AMU 250 the Programming Instructions AMU 250 and Prelimi nary Service Information AMU 250 This group of documents was probably worth a lot more than the radio without them no conver sion would have been possible A quick check inside the radio revealed that it was the deluxe 8 channel model Although the radio is synthesized it dates back to 1982 and does not have any high tech microprocessors or a fancy display Instead the channel programming is stored in a diode matrix Each transmit and receive channel has a set of 16 diodes in a SIL package Diodes are cut for a logical 1 or left connected to channel ground for a logical 0 These diode arrays are soldered onto a pair of circuit cards that fit into edge connectors on the transceiver s main circuit board Rotating the channel switch causes the common cathode line of the appropri ate diode array to be grounded and the binary data is then made available to the synthesizer s divider inputs The phase lock loop frequency synthesizer is based on a Motorola MC145152P integrated circuit I had some experience with this type of circuitry back in 1983 at Bury Radio Society in England where we had been modifying UK 27 MHz FM CB equipment for 29 MHz FM Some of the inexpensive CB radios employed the Motorola MC145106 IC and shifting the frequency
8. der donating a couple of dollars to help offset the cost of the table Our next meeting is March 1 2009 at 3 00 PM at Hudson Valley Hospital Center As always ALL are welcome I look forward to seeing each of you there 73 de Greg KB2CQE Well done Joe W E ai B 4 i P j E i f o FFO 7 a ia 7h E gt y E q ag Pi t E m as 7 E g pee Sa E TTF ifar p TE i r EFA S zal EE Em Fa i Pa 1 Joe WA2MCR just received this certificate from CQ Magazine for the 2008 World Wide 160 Meter DX Contest where Joe won Ist place single operator low power SSB New York 12 United States 1 2nd area PCARA Officers President Greg Appleyard KB2CQE kb2cqe at arrl net Vice President Joe Calabrese WA2MCR wa2mcr at arrl net Contents Special conversion edition Consider conversion KB2CQE Adventures in DXing N2KZ Uniden conversion NM9J Quick Icom repair WorldRadio online Stamps jump up N NOUN e PCARA Update March 2009 page 1 Adventures in DXing N2KZ DTV Conversion Confusion February 17 2009 has come and gone and all the major television stations in the New York City area are still broadcasting analog signals Due to a heavy handed request by our new President the grand switch off of analog TV broadcasting has been delayed until June 12 Adding to the confusion stations who are moving to new frequencies to broadcast digitally can apply for a further extension of their analog op
9. erations With FCC approval you may see nightlight broadcasts telling viewers to switch to digital for a full month from June 13 through July 12 Will analog ever end Channel 22 WWLP Springfield MA switched to all digital on February 17 Some broadcasters are not eligible for analog nightlight operation Local channels 7 11 and 13 are going to be using their current analog frequencies for their new digital service They won t have old analog frequencies to transmit on On the other hand NYC channels 2 4 5 and 9 may be seen on their VHF frequencies into July These nightlight broadcasts will provide TV DXers with a unique one time only opportu nity for E skip viewing loaded with stations continually sending IDs making them very easy to identify Did you ever think analog broadcasts would end with the best DX test of all time Random is a good word to describe what TV DXers might see Some stations will be on the air and some won t The potential for catching new TV stations for your totals will be quite good When the analog world finally ceases on July 12 all that will be left to see will be Canadians Mexicans and rare stations from the Caribbean and South America A few American low powered analog stations will also still be operating With the band suddenly empty I can t imagine what might be seen It should be a new world The end of low band 56 to 88 MHz television broadcasting will also brin
10. g new freedom to six meter amateur radio operations Monster QRO operators on six meters will no longer worry about causing QRM to TV Channels 2 through 6 because no one will be watching anymore As TV channels become abandoned one by one another type of activity is already being seen pirate television Members of the Worldwide TV FM DX Association are reporting clandestine broadcasts popping up in several markets across the U S A Never underestimate the power of six meters The potential for sporadic skip is always alive E skip meteors auroras and even the moon can bring in exotic catches Listen to 50 098 MHz for CW 50 110 MHz for overseas USB and 50 125 MHz for domestic USB DX You never know when the band might light up When it does the activity is exciting I might reach 100 grid squares someday after all Determined FM Hobbyist Dobbs Ferry lawyer Marc Sophos has been trying to be a self sustaining FM broadcaster since his high school days He started his quest as a teenager by providing audio for cable TV public access channels and tinkering with Part 15 home broadcast kits Marc built his own complete automated broadcast facility in his attic bedroom while he worked at a variety of metro area broadcast stations for experience and sustenance Years of saving his pennies fund raising and deal making culminated in 1991 when Marc finally was granted an official FCC broadcast license for a non commercial station based in Ossi
11. io Association Mail PCARA PO Box 146 Crompond NY 10517 E Mail w2nyw arrl net Web site http www pcara org PCARA Update Editor Malcolm Pritchard NM9J E mail NM9J arrl net Newsletter contributions are always very welcome Archive http home computer net pcara newslett htm PCARA Information PCARA is a Non Profit Community Service Orga nization PCARA meetings take place the first Sunday of each month at 3 00 p m in Dining Room B of the Hudson Valley Hospital Center Route 202 Cortlandt Manor NY 10567 Drive round behind the main hospital building and enter from the rear look for the oxygen tanks Talk in is available on the 146 67 repeater Apart from holidays PCARA Repeaters W2NYW 146 67 MHz 0 6 PL 156 7Hz KB2CQE 449 925MHz 5 0 PL 179 9Hz IRLP node 4214 N2CBH 448 725MHz 5 0 PL 107 2Hz PCARA Calendar Sun Feb 1 PCARA meeting Hudson Valley Hospital Center 3 00 p m Hamfests Sun Mar 8 LIMARC Long Island Hamfair amp Electronics Show Levittown Hall Hicksville NY 9 00 a m Sat Mar 28 Orange County ARC Spring Hamfest Town of Walkill Community Center 2 Wes Warren Drive Middletown NY 8 00 a m Club Table Sat Apr 4 Splitrock ARA Hamfest Roxbury Senior Center 72 Eyland Ave Succasunna NJ 8 00 a m Sun Apr 26 Mt Beacon ARC Hamfest Tymor Park LaGrangeville NY 9 00 a m Club Table VE Test Sessions Mar 1 Yonkers ARC Yonkers PD 1st Precinct E Grassy Sprain Rd 8 3
12. light WDFH was granted approval to move their antenna from Ossining down to Pleasantville and raise power to 53 watts This new central location and much stronger signal now provides a wide coverage area serving a large portion of Westchester County WDFH s local oriented program ming is eclectic and original produced entirely by Buchanan Tag MrT j E i W an FCC service area for WDFH 90 3MHz FM volunteers If you are looking for something new and very different to listen to WDFH might become your New Year s gift For more information look at http www wdfh org or tune in to 90 3 FM The little station once known as the voice of Dobbs Ferry High School is now the home of America s most Determined FM Hobbyist AT Sprint II Last month I mentioned that I had begun experi mentation with another QRP kit This time it was an AT Sprint II designed by Steve Weber KD1JV This self contained battery powered four band transceiver is an extraordinary concise lightweight design specifically intended for backpackers and mountain toppers Powered by AAA batteries the unit weighs nearly nothing The ATS II is capable of operating on 20 30 40 and 80 meters CW and features a tight band pass filter of about 500 Hz and a built in keyer for a CW paddle It is quite a rig The unit is squeezed into a plastic box whose halves slide together This allows for easy battery changing and band switching Your operating band is de
13. ning New York Marc spent long hours and all his money to build an impressive broadcast studio on the second floor of an old office building in Ossining Without tower space for his two bay Shively FM antenna he mounted it on the roof of the studio building This became a fatal flaw The building also housed a music school and his FM signals began creating havoc with guitar amps and radios in nearby local stores It was a sad retreat when Marc had to disassemble all his work in the office building He found compro mise in a new arrangement The WDFH antenna was moved to a new higher location up atop the hills of Ossining Marc built a self contained automation system right at the transmitter tower and got himself back on the air The higher location meant that he had to reduce his power to maintain his former coverage area to gain FCC approval Unfortunately his low power broadcasts were hard to hear at any distance from his antenna due to close spacing with other stations on 90 3 MHz For several years Marc received a great boost PCARA Update March 2009 page 2 working with Mercy College Marc provided his license and transmission equipment Mercy provided studio space and legions of broadcast students The two parties worked hand in hand to create memorable community programming This arrangement came to an end and Marc had to revert to another scaled back operation The clouds have now cleared again and Marc is enjoying new sun
14. on The Service Manual provides instructions for adjusting the voltage controlled oscillator VCO this was simply a matter of adjusting a trimmer capacitor inside the VCO shield cover while monitoring the voltage on a nearby test point I had already checked the various test voltages while the radio was operating on one of the commercial channels and it did not take long to adjust to the correct value on 447 8875 MHz This was followed by peaking of the transmitter s RF circuitry according to the service manual In a short time RF output power began to appear on the power meter and the red TX LED lit up The transmitter could easily supply 25 watts on this new frequency m E Inside the AMU 250 The two channel boards containing the diode arrays for frequency programming are indicated by white arrows More useful frequencies Having proved the point that the radio would tune down to 440 MHz it was time to program some useful frequencies into it using the diode arrays The first circuit board already had four diode arrays soldered on and I took a careful look at whether they could be reused I was trying to change as few of the diodes as possible Here s how I reprogrammed the first channel for the KB2COE repeater 8 N O 5 A 0 Channel 1 RX 463 925 MHz 011110101 000010 change to RX 449 925 MHz 011011001 000010 Channel 1 TX 468 925 MHz 100101001 100010 change to TX 444 925 MHz 011111001 100010 Only three change
15. or the phase lock loop s N and A inputs is as follows 8 N O 5 A 0 100000100 000001 where a 1 means the diode in that position is cut and 0 means the diode remains in place Would it work My guess was that all that was needed to convert the Uniden down to 440 MHz would be to change the patterns in the diode arrays then re peak the tuned circuits The first thing to do was to draw up a table showing the binary patterns needed to cover the amateur band In the 29 MHz FM CB conversions I had written a little BASIC program to do this job and ran it on my Commodore PET with output on a dot matrix printer A quarter century later we have more powerful tools available and I prepared the new table of binary patterns for 440 450 MHz using Microsoft Excel For an initial test I chose a transmit frequency from the table that would need as few diodes as pos sible O aN 0 5 A 0 TX 447 8750 MHz 011111111 011110 TX 447 8875 MHz 011111111 011111 TX 447 9000 MHz 011111111 100000 The diagram shows how one of the 16 diode arrays would be cut x for a transmit frequency of 447 8875 MHz of tid tt t tiodl iiiI Common cathode diode array as used in the AMU 250 This particular frequency 447 8875 MHz only needs two diodes in positions N8 and A5 to program the radio I tack soldered the two diodes onto an empty channel position on the circuit board connected the transceiver to a dummy load and switched
16. re the next attempt I carried out some online research and found a copy of the IC 3200A E Service Manual in PDF format at The Repeater Builder s Technical Information Page http www repeater builder com This is an excellent site for all things related to repeaters and amateur FM activities Remem ber to check here when you have any technical ques tions about surplus FM equipment The Icom Service Manual contained an exploded diagram entitled Front Panel Disassembly and a drawing of the Logic A circuit board layout These pictures suggested it might be possible to reach the Icom IC 3200A with unlit liquid crystal display Is it switched on PCARA Update March 2009 page 6 front panel lamps by removing items from the front of the radio rather than by starting from the rear of the front panel and removing layer after layer of circuit boards The diagrams were correct The order of removal was as follows disconnect power from the radio remove top and bottom covers remove four screws holding plastic front panel to metal sub chassis Pull off three front panel knobs and unscrew the front bezel off the microphone connector Pull the plastic front panel straight off the radio taking care that the eleven push buttons don t fall out of the plastic panel This reveals the liquid crystal display mounted on the front facing side of the Logic A board See photo IC 3200A with plastic front panel removed By
17. rth conserv ing resources by keeping an older radio running for a while longer There are a few features missing from these older radios they might not have many memo ries but they also have no noisy cooling fan no compli cated menus to set up and no wide band front end wide open to cross modulation A good bargain all round WorldRadio online The first two issues of WorldRadio Online February and March 2009 are now posted on CQ Magazine s web site To download and view the issues go to the CQ home page at http www cq amateur radio com and click on the World Radio Online box These are large Acrobat PDF files 12 13 MB in size Icom IC 3200A afer LCD backight was repaired NM9J Stamps jump up The price of a first class stamp will increase 2 cents from 42 cents to 44 cents on Monday May 11 Forever Stamps intended for mailing 1 ounce letters at any time can still be used after the price change without the need for any additional postage While the 44 cent stamp will be sufficient for a one ounce letter the cost of a two ounce letter will also increase by 2 cents to 61 cents Postcards will increase by 1 cent to 28 cents The International rate increases from 94 to 98 cents for a 1 ounce air mail letter Canada and Mexico are less Remember to keep your QSL Manager stocked with envelopes having sufficient postage PCARA Update March 2009 page 7 Peekskill Cortlandt Amateur Rad
18. s were needed on the first diode array and only four on the second shown above in bold Sounds pretty simple But it was more compli cated in practice First I had to completely unsolder the two 18 pin SIL packages from the circuit board using HA047 16 diode array from Uniden AMU 250 my trusty solder sucker The diode legs then had to be folded out of the way or rewired to a previously cut position Finally each diode array had to be soldered back onto the circuit board again It was evident that I wasn t the first person to do this as the circuit board showed signs of previous channel changes with tracks lifting off the substrate and the board warping with the heat There is no wiggle room between the SIL pack PCARA Update March 2009 page 5 ages everything is packed together just as tightly as possible After a couple of tries the two diode arrays were reprogrammed and soldered into place I repeated the RF alignment obtaining good power output on 444 925 MHz However operation through the KB2CQE repeater requires one more thing a transmit PL tone of 179 9Hz This particular Uniden radio features an 8 channel CTCSS tone generator with a separate trimpot for each channel I had to reconnect a wire link then adjust the first trimpot for the correct PL frequency Shortly afterwards I was able to bring up the repeater on 449 925 MHz and had a contact with the man himself Greg KB2CQE I reprogrammed the next channel
19. termined by exchanging small rectangular boards that slide into two sockets on the main board The ATS II produces a hefty signal of about five watts with minimal current draw igl M AT SPRINT lle I found a few issues with rs this trans AFG ceiver You ATT must be very P careful ex changing band eei RIT TUNE T modules to MENU E HEG 1 i Gi avoid the l horror of gray AT Sprint II CW transceiver smoke Align your pins exactly or bear the consequences I found the band filter very tight for casual use Unless a replying station is close to your frequency you simply won t hear them There is a provision for RIT but you must re member to cancel its operation before you move on to another station Frequency adjustment sending speed and fre quency readout are all achieved by manipulating four delicate looking red pushbuttons that stick out through the plastic box This seemed fragile to me To move up in frequency you would toggle one switch then use another switch to toggle down in frequency It would have been nicer if this operation were consolidated into one switch Navigation of functions takes a little getting used to Again by manipulating the onboard switches you can change frequency and have it read back to you in Morse Code you can change the speed of your CW paddle and even record a message or put the unit into beacon mode repeating a message time and again Each one of these features is reache
20. was a matter of modifying the synthesizer s binary inputs retuning the voltage controlled oscillator and re peaking the RF circuits We want information information Modifying the Uniden radio followed a very similar pattern The first requirement was to find a data sheet for the Motorola frequency synthesizer chip this was available from Freescale Semiconductor s web site http www freescale com From the data sheet I learned that the MC145152 is programmed by sixteen parallel inputs for the N and A counters The N range is from 3 to 1023 and the A range is from 0 to 63 The MC145152 is designed to drive an external prescaler extending its frequency range from a few megahertz into the VHF and UHF spectrum A formula is provided that relates the total divide value N to the synthesizer input frequencies frequency into the prescaler NPA frequency into the phase detector where N is the number programmed into the N counter A is the number programmed into the A counter and P is the divide ratio of the prescaler Here is a sample calculation for the Uniden AMU 250 operating on a transmit frequency of 450 0125 with its in loop oscillator on 320 MHz and a prescaler divide ratio P of 40 Frequency into prescaler 450 0125 in loop oscilla tor 320 000 MHz 130 0125 MHz SO N 130 0125 MHz 0 0125 MHz 10401 260 x 40 1 PCARA Update March 2009 page 4 For N 260 and A 1 the binary pattern f
Download Pdf Manuals
Related Search