Work continues on this little guy. I was having some problems with the audio IC, I couldn't get it to work above 15V supply, the audio would cut out on peaks. I used some junkbox cores for the filter inductors, and the IC doesnt like them. I built another modulator card with different inductors, and after a few wiring snafu's were corrected its working happily up to 31V input. The datasheet says it should work up to 36V, but TI has been know to lie before. I hooked this test modulator up to the remainder of the transmitter and all seems to be well. The finger scorch factor implies something around 20W carrier balls-out...that's all she wrote. Still, not bad for a proto build. Proper scematics coming later in the week if all goes well.
Re the Harris exciter... Most of the AM stereo exciters aside from BE's were setup for a single frequency and it was a job to move them somewhere else. That said, I've never seen the docs for the STX-1.
+-RH