I'm curious to hear of the results of the solid-state class C amp used on AM experiment, I've got the 100w PA section from a lowband (~6m) highway patrol Motorola Micor that I used with the funny Cherokee 6m FM ht long a ago. (a POS radio, imho, btw)
73,
Jason kf6pqt
Hi Jason,
Check the Micor schematic to be sure they are not using a base-leak or a self biasing scheme on that class C amp. Fixed bias is what you need - but it could be modified with a zener if so.
Another way to test it is to inject in an RF carrier and vary the level. Measure the base DC bias (on the DC side of the choke, on the other side of the RF) to see if it stays fixed or varies. You want rock stable bias, cuz with linear drive to the base, under modulation the self bias would vary and cause unwanted distortion.
The Mot Micor is a beautifully built rig...almost like mil-spec. Back in the early 70's I was a Motorola tech and used to repair and maintain them.
T