How low can we go? In this video we explore the Self-Quenching Pentode circuit in the Shortwave Frequencies. What are these Space Charge valves and can you really operate a super regen at 12 VDC?
Super regen at 25 MHz! Ah yes! That brings back fond memories of my Sears Walkie Talkie Base Station I had back when I was an early "tween" in the 70's. Sure it picked up CB because it had to in order to hear who you were talking to. But the receiver tuned all the way down to almost 12 meters. I remember very vividly listening to WWV on 25 MHz back before they were constantly mentioning "Cordinated Universal Tom". It used to be: "21 hours, 31 minutes Greenwich Mean Time". I even heard shortwave broadcast stations on the 26 Mhz SWBC band. I could hear the hams on 10 meters but I couldn't tell what they were saying due to super regens couldn't detect SSB. Thanks for bringing back those good memories Mike! Also don't forget about the noise canceling phasing circuit you said you were going to do a vid about - I'm really interested in that. 73 de WB8YMV.
If you are going with 2 stages, make one a reflex stage. It can serve as and RF preamp and also as an audio amp. I did this many years ago with transistors and made it work. The tricky bit is mix together the RF amplifier and audio amplifier in a manner that keeps them from interacting in a bad way. The way I did it was to have more RF in the detector stage cause the audio stage's current to decrease.
As always, it's a great video, Mike. Your video gives me energy and inspires me to do something. That's way I'm still alive. I look forward to seeing Part4 video soon. Thanks! Chappy Happy.
I've used those PA speaker transformers on the output of 1920's receivers. I also used one on the output of a battery powered tube guitar amp I built. Those transformers are great for such uses.
Those PA system transformers are made to distribute audio power with a way to share and adjust the 70V AC (600 Ohm usually) source over many speakers. They are not designed to run DC current through them, and the impedance can be incorrect, and power efficiency can suffer during DC core saturation. The results vary wildly based on the particular manufacturer. I guess my message is that they may look the same, but are are not the same as your typical 50C5 or 6V6 to 8 Ohm output transformer.
Thanks, great video as always. I check CB all the time to to see if 10 meters is open. Those guys will have dozens of people talking all over the US and 10 meters has nothing. Time to start calling CQ.
@MIKROWAVE1 I worked at RadioShack years ago. I told them, when they first dropped the catalog, that they would eventually go out of business. That catalog was the glue that held them together. My opinion! But my prediction was spot on. I spent hours going page by page. Others did too. Anyway! Great channel. Love them radios!
Thanks for watching. A dive into superregens - not very deep one cause we did not cover external quench...but we are tiring and its time to finish it up. Meanwhile collect parts over the next couple of weeks!
Love your series on Regens/Super Regens. I have a one valve Regen approx 3Mhz-8Mhz on 12volts works great on Broadcast and Aviation Weather stations and Amateur Bands😀
Really enjoyed this video...and a good intro to tubes for those, like me, are not quite comfortable with high voltage. Some very good learning points as to why you need high voltage. Sourcing the tubes at a reasonable price in the UK is not going to be easy. Count yourself as blessed for cheap parts in the USA. Thanks Mike!
@@MIKROWAVE1 LoL! :-) You tease me Sir! We have Spring bulbs in the garden (yard) and had light bulbs in the house but like everyone else, we are going LED. I was being polite when I used the American "tubes" as you know, they are valves to us! LOL Whatever we call them, you produce fun and educating videos and I'll take your advice and see what old valve sets I can plunder. ;-)
In the '67 HB, there was a one tube UHF transceiver for 450mhz using a single 6CW4 tube as a super regenerative detector and modulated oscillator transmitter. It was a portable with a 45 volt B battery and a 6v A battery. It used three transistors in the audio amp / modulator with a small tube power transformer as the modulation / af output transformer. Did you know that there were space charge Nuvistors (8056)? CB Band? That's the Citizens Band Band.
I like the term collector for anode. After all, the "plate" which is not plate but a cylinder, is collecting electrons. In fact, in other languages, "plate" is called anode.
Upon discovery of your channel, I once again became infatuated with the crystal radio. Just wondered if you've ever utilized a full wave or bridge demodulator? I built one about a hundred years ago (LOL) and the result was a substantial increase in output signal.
Space Charge tubes by RCA were used in car radios in the 50s to stave off the transistors also it meant that they could get rid of the Vibrator that was used to generate 120V, Space Charge tubes were made as they were safer to use because there was no shock hazard unlike the vacuum tubes that use a 120V B+ and a heater of 6V.
Yes they still used a transistor for the brute work of driving the speaker. I saw women building car radios in an old Motorola plant in Arcade NY in 1978. I was trolling for a Co-Op position. They were for Volkswagen. They also made alternators for VW. Imagine a US manufacturing company exporting to a car company in Germany today?
Lord Mountbatten of royal fame, got his start as a young signals officer in WW1 DFing the German Regens whistle on their battleships. All with a big loop antenna.
@@MIKROWAVE1 ja! Und. the camp guards at German prison of war camps found "home spun" radio via RDF. From stolen tank head sets. Even our troops. Fought over a dead tank or "canpf Kar." for pieces so as to hear news from home. Old air borne sgt AMSTUTZ told me. They were of uncommon quality. Thanks again for the good show. Danke zier. Kv4li.
Your videos on all types of RX and TX are SO delicious! Thank you for all the effort you put in! (get VERY much appreciated!) Would you please also display or name the sizes such as #28 and inch and so on in Milimeters? Healthy and Friendly Greetings from the Netherlands! Rob
WWV transmits on 25 MHz on an experimental basis. I have received it (75 miles to its South) a few times, over the past 12 months or so. Very faint, and distinct only at the top of the minute.
Great Video Mike. With you demonstrating the value of all those old TV tubes (with great VHF performance), I was lamenting about how many thousands are buried in landfills, that if dug up would probably still work just fine! Question: Would it help performance (of whatever type of tube used) to place an adjustable voltage divider on the grid to set a working threshold so that the tube didn't have to purely depend on the RF incoming signal to bias the tube; also what about the distortion that seems still evident?
The self-quenching circuits like the "Flewelling" are not known to be distortion-free but they are simple and usually are pretty forgiving to parts substitutions. There are better circuits. I just stuck with a two basic circuits shown in the ARRL Handbook.
@@MIKROWAVE1 OK, I was just comparing that with the other regens that you’ve done that seemed do you have really nice sounding performance. Also I asked about the biasing, could be bias be adjusted with the divider to help the conduction of the tubes?
@@SpinStar1956 These super regens are pretty nasty - and remember we are trying to detect FM, on an AM receiver, which means you are doing slope detection at best. I have seen a full discriminator formed with a balanced dual super regen that puts two identical regens back to back and ads them in a center tapped transformer on the output.
@@MIKROWAVE1 when I was young, everyone said build a regen, and I had the most miserable 😩 time trying to get them to work so I gave up! I would make DC’s and supersets and had so much easier time of it. You’re definitely a real intuitive builder so even though I not highly interested in them, it’s still great to see you work through the topologies and problems! 73...
Dear BORG, please send these KORG tubes for my inspection. It sounds like we misuse them? But they do something that they were not originally intended for it seems. They amplify!
You've re-gen'd my interest in radio. I've built dozens of xtal sets, but I'd like to start with shortwave and CCW. I'm thinking of building the "Experimenter's Power Supply" in one of Lindsay's "Impoverished Radio Experimenter" books. Could you recommend another type/model? I really enjoy your channel.
