Yaesu FT-101B S/N 5C 32 0034

The FT-101B pre-dates the WARC bands, and so only has the "classic" ham bands of 160, 80, 40, 20, 15 and 10 metres.

There is a 10MHz WWV position on the bandswitch, and many '101B users have modified their radios to transceive on the 30m band, my radio is at present unmodified in this respect.

The previous owner fitted a replacement double-balanced mixer module by G3LLL, and one or two other minor modifications were carried out, which will be documented here in due course.   The radio is fitted with the manufacturer's optional 500Hz CW filter.


I previously reported a lack of output on the 15m band, this has been cured by following the alignment procedure and aligning the driver stage.

This is a "late" 101B, and at the time of writing it is serviceable, but with the following niggle :-

The receive audio sounds harsh, especially in CW mode, where it is downright unpleasant! This one could get interesting ...

I believe that the problem is harmonic distortion, more evident in CW reception mode because the harmonics of CW tones are very obvious.

I devised a test whereby I fed the internal AF output amplifier from an external source, the result was very pleasant audio.

I have used a second receiver to demodulate the IF output from the '101B, and this also produced pleasant audio.

As a workaround, I am currently using an IF board without the CW fitted, and the resultant audio is just fine.

At one time I suspected a shortage of LO drive to the product detector, but I have a healthy 1.5V peak to peak at the point in the circuit common to the balanced modulator and demodulator, and I believe this to be a fairly normal value.

Bradley L Snyder W3JXQ has posted some information here about how to set up the clarifier on the '101B. I suspect the principles apply to most if not all the FT-101 series and their close relatives.

Page updated :- Aug 30th 2010