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Author Topic: Two tube (56 & 42) regen rx and Hartley tx  (Read 2553 times)

Posts: 814

« on: October 26, 2012, 07:52:43 PM »

I have been working on this little rig for sometime. it all started when I realized a regen is just a oscillator with not quite enuf voltage to break into full oscillation. This is one of the circuits I built to test that idea. I originaly built a hartley based regen and then switched the phones and pot out of the circuit allowing full voltage to the plate and bingo I had a working transmitter. Switching back I had a working regen rx same frequency. Now a single triode regen is not much use .Not enuf volume to be practical. It needed a AF amplifier to bring it to life. I chose a 42 tube and made an amp. I tried feeding it from the 56 tube with normal methods but the regen did not want to work when loaded that way. I built a tuned circuit for the 42 and used the 56 osc in TX mode to drive it. That worked immediately.  Summer came and it sat . Yesterday I got back at it after a conversation on regens and regen muting during transmit. I rebuilt the regen as it was first but subbed an audio transformer where the phones were and hooked the secondary up to the grid cap and grounded the other end. It worked but was very weak. I switched everything to TX mode to make sure the transmitter still worked just in case I had messed up.  All was fine. I surmised the 42 tube did not like the 8 ohm secondary of the audio ransformer. I would have used a 1:1 ratio transformer but dont have any so I took another old audio transformer and hooked its 8 ohm section to this transformer's 8 ohm section then fed the grid from its primary. I now had a 1;1 audio transformer albeit a bit crude and unconventional. It works like a charm. Good volume on receive and good power on transmit. The project is a complete success. Oh it still needs teaking but just tweaking. It is working and usable. It has been a lot of fun designing and building it. Now I am looking around for one of those early cathode modulator circuit that could be plugged into the key jack to modulate a CW transmitter. 
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