so ive been wanting to build a regenerative receiver for a while now, finally sat down this weekend and threw one together based on a schematic i found in an old ARRL handbook from like 1987. used a jfet (2N5457) for the regen stage and wound my own coil on a piece of pvc pipe - about 40 turns of 26 gauge wire with a tickler winding of maybe 8 turns.

anyway i get it powered up and theres definitely something happening, the circuit is drawing current and i can hear a hiss when i touch the antenna terminal but rotating the regen pot doesnt seem to do much of anything. no oscillation that i can detect, no signals, nothing. the coil resonates somewhere around 7mhz if my dip meter is anywhere near accurate which is what i was going for.

not sure if its the coil geometry, maybe the tickler coupling is off, or if the jfet biasing is just wrong. i tried a couple different drain resistor values but didnt write down what i tried so i couldnt really tell you where i landed. anyone built something like this recently or have a go-to regen design that actually works first time around

regen receivers are finicky little things, been there. the tickler winding ratio is probably your main issue - 8 turns to 40 is a pretty loose coupling and you might just not be getting enough feedback to sustain oscillation. i usually start around 15-20% of the main winding and adjust from there. also the 2N5457 should work fine for this but make sure your gate bias is set right or the thing just sits there looking confused. what voltage are you running it at?

also and this is important - physical layout matters a LOT with regens. if your tickler lead is running parallel to your tank coil leads for any length you can get all kinds of weird coupling effects. keep everything short and dress the leads away from each other. took me three rebuilds on my first one before i figured that out.

i built something similar last year from a charles kitchin design, think it was published in QST or maybe it was the ARRL handbook cant remember. mine worked on the bench but when i put it in a box the regen point completely changed and i had to redo the pot range. shielding does weird things to these circuits. anyway not sure if thats your problem but worth knowing before you start chasing the schematic too hard