so ive been working on this for maybe three weeks now, started with a simple regen receiver kit i got from a supplier online but ended up just going full scratch build after i got bored with the kit. using an FET i had laying around from an old project, hand wound the coil on a pvc pipe former, maybe 80 turns of 26awg i think, tapped at around 15 turns from the bottom for feedback.

it receives fine actually picks up AM broadcast pretty clearly and i got some SW stuff on 40m which was exciting. but theres this oscillation that kicks in when i advance the regen control past like halfway, it doesnt just go into oscillation gradually it kind of snaps into it hard and then i get this loud squeal through the headphones. ive read that regens do this but i thought you were supposed to be able to back off the feedback and sit right at the threshold. mine just goes from barely regenerating to full squeal with almost no usable range in between.

not sure if its my lead dress, the coil placement, or maybe the feedback tap is wrong. the detector and audio stage seem fine on their own. anyone dealt with this before

yeah that snap into oscillation thing is classic bad lead dress or too much stray coupling somewhere. with regens the physical layout matters almost as much as the circuit values, everything needs to be kept short and the tickler winding or feedback tap needs to be physically away from the grid/gate end of the coil. if your coil is oriented wrong relative to the rest of the circuit it'll just snap hard like you're describing.

also worth checking your supply bypass caps. i had a similar issue once and it turned out to be a 100uf cap with bad ESR on the drain supply that was causing the regen control to be basically binary. slapped a 0.1uf ceramic right across the drain resistor and it smoothed right out, had a nice gradual onset after that. the tap position is something you kind of have to experiment with too, 15 turns on an 80 turn coil might be a bit heavy depending on your Q but i wouldnt change that first, check the physical layout and bypass first.

im building almost the exact same thing right now haha, what FET are you using? im using an MPF102 and mine oscillates pretty well but i havent got it stable enough to actually listen to anything yet, just RF noise mostly. curious if your audio stage is just a single transistor amp or something more involved