I really enjoy to operate my KWM 2 A. mostly ragshewing on 80, 40 and 20 m. Don't want to keep it only as a museum piece. Sometimes I have noticed that the signal levels are extremely high especially late evenings on 80 meters. QRM and noicebursts so high that the receiver almost could be blocked out are not unusual. Unpleasent audio distortion and exessive loudness is often the result. The only cure is of course to reduce the manual RF gain control. I have a dipole on 80.

These problems derive mainly from the simple AGC system I think. A better sounding audio would make me use the KWM 2 more often I thought some years ago. On the other hand I agree with all those Collins owners who say: "nothing must be changed or modified". I have replaced most of the filtercaps and some aged resistors. It was simply necessary to keep it working. I am also using the ASO DDS-2A vfo which I like and recommend very much. Its principle is very smart as it can be plugged in or out in a few seconds and does not change anything in the KWM 2.

Could something like that be done to add a new AGC, productdetector and an active audiofilter using the same principle as the ASO vfo? If you unplug 6BN8 V15 and look down at the tubesocket you can see 9 holes which have connections to the IF-transformer, the beat-osc, the AF-ampl. and also 6.3V AC among other things. How about to use the tube socket to plug in all the functions you need. The circuit board could neatly be mounted aside by means of the PM-2 "hook on holes". You need these holes available. (look at the pictures) The circuitboard contains a 6.3V voltage doubler and regulators for -12V, +12V and +6V. There is also a SL1640C product detector and an UAF 42 Burr - Brown LP filter. The hang AGC circuit is inspired from an early article in the Ham Radio magazine sept 1972 written by W1ERJ.(look at the wiring diagrams) I have set the hang time to 1.3 seconds but it can easily be changed. To keep the temperature under control both for the circuit board and the KWM2 in general. I have installed two fans underneath the hood. I have used a very smart method, which I have never seen before. The two fans are attached by means of velcro-discs. Just tear them out and put them back if you need to. No drilling no marks. The velcro-discs also reduce the vibrations. Wen the hood is opened the fans do not bother if you want to change tubes or tune the slugs.(look at the picture). It is very simple and efficient. I am very pleased with the audio quality and the extended agc. dynamic range. I have replugged the 6BN8 a few times just to notice the difference. But I am always using the adapter when I am working. I never touch the RF gain control any longer.It is always fully advanced. The big advantage with the adapter board is of course that it can be picked out and unplugged in a few minutes. And the KWM2 is in original shape again.

So far this has been a non commercial site. I have just been telling a story.