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 -------------------------------------------------------------------------- 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 Procenga 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. ÿ