K8TND’s Take on the Kitchin Regen
Some of the most popular feedback I have had on this blog revolves around the Kitchen regenerative receiver project that I took on initially back in Feburary of 2012. From time to time I still receive interesting e-mail messages and comments about other people’s designs and this one is of no exception!
Cliff Donley K8TND sent me a very interesting e-mail message about his take on the Kitchin regenerative receiver. He has made several modifications and also has some pointers to share with us. First up the schematic that Cliff sent me is the latest schematic of the Kitchin receiver that he could find: (you can click on the image below to open just the schematic in another window for printing)
Cliff told me that he has some pointers on how to eliminate the hand capacitance issues that plague this type of receiver:
“Regarding hand capacitance issues, with the tank coil being wound on a
toroidal core, that helps tremendously on my version and the
varactor/diode and potentiometers totally eliminate it.”
And here is where he gave me a tip about grounding the rotor of the capacitor to reduce the hand capacitance:
“On the older regens I’ve built, using traditional variable
capacitors, I have eliminated MOST of the hand capacitance problems by
grounding the rotor of the capacitor and connecting the stator to the
hot side of the tank circuit and then of course enclosing the circuit
board in a metal case.”
I am amazed how far this circuit design has been modified and taken to yet the next level. This is truly “open source” before that term was original coined, and it is still going strong today!
Here is a little slide show that shows Cliff’s regen that he build with the modifications: (Nice blue LED indicator light Cliff! – You can click on the slideshow to stop it to examine the photos in closer detail if you wish)
And one last tidbit of wisdom from K8TND about air variable capacitors:
“BTW Nick, I was also going to mention an old trick from way back in the
60s. If you have a variable capacitor that’s too high in capacitance and
you want to reduce it, simply put the capacitor in a vise, take a sturdy
pair of long nose pliers, grasp ONE plate at a time, starting from the
outside and YANK it out of the ROTOR. Do NOT try to remove plates from
This is a great little trick as finding the proper air variable capacitors is getting increasingly difficult and when you do find them they are relatively expensive.
A huge thanks to Cliff Donley K8TND, and thanks for sharing! I know that others will benefit from your radio wisdom.
73! de Nick N9SJA