Building my first homebrew superhet receiver for 40m and having issues with IF alignment. Using MC1350 IF amps with ceramic filters at 455kHz. Getting decent sensitivity but AGC seems to pump on strong signals. Anyone else experienced similar issues with MC1350 AGC circuit?

Running 12V supply, tried different time constants on AGC filter but still getting that pumping effect. Following the datasheet pretty closely but wondering if there's something I'm missing in the bias setup.

Had similar issues with MC1350 - try adding more RF bypassing on the AGC line. I used a 10µF tantalum in parallel with the existing electrolytic and it smoothed things out considerably.

Check your S-meter circuit if you have one - I found mine was loading the AGC line and causing that pumping. Also verify your IF gain isn't too high - sometimes less is more with AGC stability.

What ceramic filter bandwidth are you using? I found 6kHz filters work better than 2.4kHz for SSB work with the MC1350. The narrower filters seemed to make the AGC more sensitive to phase variations.