Tuesday, September 4, 2012

Technical considerations about Yaesu VX-1r

The handheld is about 10 - 15 kHz off frequency

This handheld has a little mechanical problem: The speaker touches physically the small diode shown in the photo. So with a fall-off or a big shock, the diode could be broken or get de-soldered.

The diode is a 1SV230 varicap (D2016). It is used as DCS modulator, so it can be safely replaced with a similar one, or in a desperate situation, replace it with a fixed 10-15pF capacitor. In this case, you will lost the DCS function.

Once fixed (for any of the two methods described above) you must adjust the TX carrier frequency with the small trimmer marked with a red arrow and a frequency counter.

Low modulation

If you consider the modulation level is too low or too high, you can adjust it with the two variable resistors marked in the photo. The left one is for VHF and the right one is for UHF. Please, do not over-modulate! You will create adjacent channel interference and you will have problems being received with low signals. It is preferred to be somewhat under-modulated that to be over-modulated.

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