Ham Radio 2000 #2

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Internet Message Format | 1997-12-21 | 6.3 KB

From: postmaster@asarin.ORG.AR Newsgroups: rec.radio.amateur.equipment Subject: Re: << HELP >> WANTED MODS... Date: 7 Dec 93 12:57:57 GMT Organization: ucsd usenet gateway Lines: 124 Message-ID: <gate.a497Dc1w165w@asarin.org.ar> NNTP-Posting-Host: ucsd.edu Originator: daemon@ucsd.edu Hi Chris (N0OXI) and ALL! Here are some mods for the Yaesu FT-290r mkII radio... ------------------------------------------------------------------------------- FT290.1 FROM: M. P. ("JUG") JOGOLEFF, WA6MBZ @ K6TZ BBS RE: YAESU MICRO-PHONE NUMBER MH-15 C8. MOD.: HOW TO PREVENT THE TOUCH-TONE PAD FROM AUTOMATICALLY KEYING UP YOUR RIG. RIGS INVOLVED: THIS MIC. COMES WITH THE YAESU FT 290 MK II (2 METER RIG), THE FT 690 MK II (6 METER RIG), OR THE FT 490 MK II (UHF RIG), AND POSSIBLY OTHERS. 1) TAKE THE THREE (3) BACK SCREWS OFF. 2) TAKE THE TWO (2) SCREWS OFF THE CIRCUIT BOARD TO FREE IT FROM THE CASE. 3) FIND THE RED WIRE GOING TO THE MICRO-SWITCH, IE, THE PTT LINE. 4) FOLLOW THAT RED WIRE TO THE CIRCUIT BOARD. AT THAT PLACE ON THE CIRCUIT BOARD ANOTHER RED WIRE WILL JOIN THE FIRST ONE. 5) UN-SOLDER BOTH RED WIRES FROM THE CIRCUIT BOARD AND CLEAN UP THE SOLDER MESS, OTHERWISE HUM WILL OCCUR. 6) SOLDER THE TWO RED WIRES TOGETHER AND COVER WITH TAPE OR SHRINK TUBING. 7) PUT THE CIRCUIT BOARD IN PLACE AND SCREW IT DOWN. 8) PUT THE "LOCK" SLIDE SWITCH BACK IN PLACE. 9) PUT THE REST OF THE CASE ON. 10) PUT THE OUTSIDE SCREWS IN. 11) YOU ARE NOW READY TO TRY IT OUT, SO GO AHEAD AND RE- ATTACH IT TO YOUR RIG! 12) ALL SHOULD WORK: PTT WORKS AND RELEASES, MIC PASSES AUDIO, TOUCH TONES WORK WHEN PTT BUTTON HELD, TOUCH-TONE RED "LED" STILL LIGHTS UP WHEN TOUCH-TONE PAD KEYS ARE DEPRESSED, EVEN IF PTT BUTTON IS NOT HELD DOWN, NO HUM NOTICED. ------------------------------------------------------------------------------- FT290.2 FT-290R (first version) Extensions The pins no 38,39,40,41 near HMCS45C are used for extensions. PIN No BAND STEP FM/SSB SHIFT 38 39 40 41 MHz KHz Hz -------------------------------------------------------------------------- * * 140-150 25 1000 7.6MHz 100 100 -------------------------------------------------------------------------- * * * 140-144 10 1000 1MHz 20 100 -------------------------------------------------------------------------- * * * * 140-150 5 1000 no shift possible 10 100 -------------------------------------------------------------------------- * * 144-146 12.5 1000 600KHz 25 100 (European version) -------------------------------------------------------------------------- * * * 144-149 10 1000 600KHz 20 100 -------------------------------------------------------------------------- * * 140-150 25 1000 5MHz 100 100 -------------------------------------------------------------------------- * * 140-150 25 1000 5MHz 100 100 -------------------------------------------------------------------------- * * * 144-148 5 1000 600KHz 10 100 -------------------------------------------------------------------------- * * 144-148 5 1000 600KHz 10 100 -------------------------------------------------------------------------- * 140-150 25 1000 1.6MHz 100 100 (FB for 70 cm transverter) -------------------------------------------------------------------------- * * 144-146 10 1000 600KHz 20 100 -------------------------------------------------------------------------- * 144-148 12.5 1000 600KHz 25 100 -------------------------------------------------------------------------- * * * 143.5-148.5 5 1000 600KHz 10 100 -------------------------------------------------------------------------- Thanks to F1GAN for this info. 73 Serge F1EMT @ FF6KDC ------------------------------------------------------------------------------- FT290.3 FT-290R There is a very "hard" de-emphasis in FT-290R. This can cause serious problems copying packet signals with some demodulator chips, eg. like the XR2211. By a common request, here is a modification of this popular TCVR for packet radio. It was made after a RADIO-REF article in several copies, by HA5OB, HA5DI, HA3MA and others. Increasing the intelligibility in noisy environment, this modification is also useful in FM voice communications. You'll have to add only a serial RC unit, the R being 4.7 kOhm, and C being a 1uF tantalum capacitor. Put them between the pin 9 of IC Q1019 and the collector of transistor Q1021, with the positive leg of the tantalum capacitor to the collector of the transistor. These points can be found as test points, near to IC Q1019. Solder the components together, wrap some insulation around them, then solder to the test points mentioned. That's all you have to do! With this modification, FM reception will sound somewhat noisy, but much louder. 73, Sanyi/HA3PG ------------------------------------------------------------------------------- 73's and Merry Christmas for ALL, de Ed - LU7AKC @ LU7AKC.#COL.CF.ARG.SOAM <postmaster@asarin.org.ar> .