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It looks like this circuit is from **broken link removed**.
It's not a common design, so the website should really explain it, but it doesn't.
As far as I can tell, that Q1 portion is a hartley oscillator. if it had been drawn in a nicer way, it would have been
easier to figure out. The text suggests to replace R4 with a a variable resistor. I'd suggest it is very import to do
that if you havn't tried yet, because it would get the oscillator working.
I can't figure out what the L2 and C7 combination are doing, although the circuit description is a super-regen, so
it must somehow be interrupting the oscillations. Nice of the author to tell as little as possible on the website : (
The other thing to check is that the right-side of the circuit is functioning correctly. If you disconnect the left
side of C6 and connect the left side of C6 to (say) your finger, do you hear some mains hum? Are you using headphones
or a speaker? Best to do this with headphones until you're sure it works.
Also, how did you construct this? Got a photo of your implementation? What components did you substitute?
(I ask because 2N4416 is quite expensive these days, most people use PN4416 or something else.. did you use that,
or some completely different device?).
EDIT: Even some seemingly-benign components may be playing a role. For example, the R6 and R3
combination look to be some sort of feedback through R2. Unfortunately I'm just not familiar with FM super-regens.
According to ARRL guide, it may be explained in Kitchin, “New Super Regenerative Circuits for Amateur VHF and
UHF Experimentation,” September/October 2000 QEX which I don't have.
Give us details how have you implemented that design by attaching some PCB/board photos of the actual circuit. There are so many possibilities for small errors to ruin your circuit, so you don’t expect start guessing what’s wrong/missing there... :roll:
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