OM Jeff, from Traverse City, MI, wrote the other day, asking if I would share the circuit diagram for the single-tube regen receiver I described just before the holidays. I told Jeff I'd be happy to share - but reminded him that I was just riffing on an idea for my own entertainment and suggested he might do better to look elsewhere for more reliable designs. Jeff found lots of other options - but he left me thinking...
It seemed like a good idea to document what I had done with the regen - not with the implication that it is either novel or even especially worthy. Simply for the record - my record.
So, here's the schematic of my little receiver...
As I said, nothing unusual or novel - just (literally) what came to hand quickly and what worked (just about).
My regen and tuning coils (L1 and L2) were wound on a 35mm diameter former and my tuning coil ended up with 6 turns to get me on the 40m band with the tuning capacitor you see in the photo on the original blog post.
I was running with a power supply of B+ = 40V (or thereabouts) and taking the AF output into the high impedance input of an active speaker (or the line input of a computer) for amplification.
The only other vaguely interesting thing about what I was doing was the little valve-holder I made with a conventional B9A chassis-mounting socket, a pair of M3 standoffs and a scrap of PCB material...
This allowed me to mount the tube (/valve) upright on the "breadboard" base with just a pair of woodscrews.
Now I've documented what it was, I can take the receiver to pieces with a clear conscience and free up a little more space in the shack - to fill up with more gloriously pointless experiments. And perhaps when I'm visiting my friends up in the Thumb of Michigan, ahead of this year's FDIM, I'll try to contact Jeff on 40m and thank him for motivating me to pull together this circuit diagram!
...-.- de m0xpd