so anyway ive been poking at this thing for about three months now and last night i finally heard something on it that wasnt just noise. built a single conversion superhet with a 455khz IF, nothing fancy, just salvaged parts from old radios plus some stuff from the junk box. the mixer stage gave me absolute hell - i think i had the injection level too low from the VFO for the longest time and it just wasn't converting properly. once i bumped that up it suddenly started working like... reasonably well i guess.

image rejection is pretty bad honestly, i knew going in it would be since i didnt build a proper preselector, just a simple tuned input stage. getting some bleedthrough on the image frequency but for a first attempt i can live with it. IF transformer is wound on a random ferrite core i pulled out of a dead switching supply, seems to be working but i have no idea if im anywhere near the right permeability for 455khz.

anyone else gone through this with a first superhet build? curious if the image rejection thing is worth fixing now or if i should just finish the audio chain and call it done. the AF stage is just an LM386 which i know everyone hates but its what i had.

congrats on getting audio out of it, thats honestly the hardest part of a first superhet - getting everything aligned enough to actually pass a signal through. the image rejection thing is always gonna be a compromise without a decent front end filter but honestly for a learning build it doesnt matter that much. id say finish the audio stage and get something listenable first before you go back and fix the image problem, otherwise you'll be chasing two problems at once.

the ferrite core for the IF transformer is a bit of a wildcard. if it works dont touch it, but if you find your bandwidth is way off or the thing is peaky and unstable that might be why. proper IF cans are like a dollar each on ebay, might be worth grabbing a few. and yeah everyone dunks on the LM386 but for a junk box build its fine, just put a small cap across the gain pins or it'll oscillate on you.

image rejection on a single conversion with no preselector is just gonna be what it is, i went through the same thing on my first build. ended up adding a double-tuned bandpass filter ahead of the mixer later on and it helped a lot but its a whole other project basically. for 40m or 80m you can get away with a pretty simple L/C filter though, doesn't have to be complicated.

also curious what you used for the VFO - thats usually the part that bites people, stability wise. mine drifted like crazy until i put it in a little shielded box and let it warm up for 20 min before tuning around.