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A nice and simple regen receiver

Posted: Fri Aug 25, 2023 10:11 am
by Andrew (grayhat)
If someone here likes fiddling with a soldering iron, here's the schematic for a regen


I'm posting it just since I like how well it's designed while being simple, let me start from the input stage, the common gate JFET does multiple duty, not only it acts as an impedance matching device, it also works as a preamp/buffer and, thanks to the very high I/O isolation, it avoids leaks from the regen oscillator to the antenna, at the same time it also avoids that the antenna movements (e.g. wind hitting a wire antenna) detunes thee receiver; the next stage, that is the regen one is nice too, it's built around another JFET and since it uses a variable capacitor for the regen control, I trust the author about the fact that the regeneration is really smooth, and then there's the nice touch of the audio filter, which helps improving the readability and, last but not least important, the voltage regulator which will keep the voltage stable and, by consequence, will stabilize the tuning and regeneration

Again, nothing special, but I like the simple, straight and good design of that receiver, and thought to post it here

P.S. the only thing I'd probably add would be a volume control for the LM386 amplifier; the input attenuator already "doubles" as volume, but sometimes one may want to lower the attenuator to increase some signal while at the same time keeping the volume low :D ... plus, using for the volume a pot with a switch, will allow to use the volume control as the on/off switch too

Re: A nice and simple regen receiver

Posted: Mon Sep 11, 2023 3:15 pm
by Andrew (grayhat)
And here's another interesting circuit

it's a superhet based on the classic NE602, but with a difference, the LO is a regen stage based on the LM386 (yes, not kidding)
SW Superhet with Regen IF.png
SW Superhet with Regen IF.png (83.03 KiB) Viewed 22561 times
that "hack" allows to improve the performance of the receiver and at the same time, allows it to receive SSB signals, not bad imHo

Re: A nice and simple regen receiver

Posted: Mon Sep 11, 2023 9:21 pm
by 13dka
At times I regret not having gone down the DIY electronics rabbit hole and I still find the thought of making simple but powerful radios interesting. What curbs my enthusiasm though is the mechanical side, how to make not only something that works well and looks good, but something that has a proper dial with some degree of resolution to find stations or log them to cater for me being spoiled by digital readouts. :) I remember how it was an adventure not knowing exactly what the frequency is though, and having to wait for some station ID. :)

Re: A nice and simple regen receiver

Posted: Thu Feb 01, 2024 4:41 am
by Omega-TI
My first Regen Rig was a Radio Shack Globe Patrol kit that I built back in 1977. It was an anemic little radio, but I was still able to pull in Radio Nederland, Deutche Welle, the VOA, HCJB among others. I regretted getting rid of it when I enlisted in the USAF, but a few years ago I paid through the nose to get another one for the nostalgia. After I get my loop antenna hooked up this spring I may hook it up just to play around like in the old days.