One of the few things my Dad and I worked on together was a junk box three transistor (germanium) AM BCB regen receiver. We lived a half mile from a 5 KW AM station, so simple crystal receivers were useless. The receiver we built used a 4" ferrite rod antenna with a tickler coil wound on the end, and we spent many hours getting the correct number of turns and position of the ticker coil on the ferrite rod to get regeneration control across the band. We also swapped out the first transistor many times to get a hot transistor that was 'just right'. I was simply amazed at the time on number stations we could pick up using that homemade receiver. Something I thought was only possible with a superhet given our proximity to the radio station.
Wow! That was a great introduction! Gaining insight into how hard getting bipolar transistors to behave in regen circuits compared to tubes or FETs, is another rite of passage for many.
First of all, thanks for explaining the hair cut. You and Bert must have an excellent barber. You have some nice looking radios. I'm still learning about receiver designs after 31 years in ham radio. Great video! 73.
My intention is to create a 1929 transmitter from your 4 part series. These regen circuits are going to take some rewatching, as for the most part, they are still a magical mystery to me 🤪
@@MIKROWAVE1 I did it on bipolars and fets. It works well, but doesnt give as much satisfaction as on tubes. I have homebrew regen, which has parallel connected tubes connrctors. I can quickly change 6k13п to 6k4 (6sg7) in rf amp, for example. and its very cool. In addition, i made agc in rf stage. And i can adjust to the first or third grid (if i apply 6ж2п or 6ж10п in rf stage). sorry for my english...
It has been said that when one listens to Mozart, he becomes more intelligent. I feel the same way about your videos. I have been fascinated by radio since I was 10 and have learned so much from your presentations. 73-Dave, N0ALN
I recently restored a DKE38 and a VE301 (both regens) and they work remarkably well and are quite stable. They were made to be cheap so that the average German could afford them and yet they perform excellently. I have also built a few regens in by time too. One of my favourites is the Hikers two (from Australia). It runs off of a pair of 9Vs and a 1.5 V battery. It is a beautiful radio. I love the R29 regen you show off here too. I think I might make one of those. I love those with the coupling link. The DKE38 has one of those as well.
The Refurb-Rebuild is coming along on the Steampunk Portable. I have a good radio now and am in the middle of evaluating the plug in coils. I can say on headphones it is doing a great job on 20M, which kind of shocked me, and it is blasting on 40M and 80M. Three of the coils are misses. Missed the band completely or tickler way off. That is why 5 coils for 3 bands!
Dear Mike, I think the 1H5 is sounding poorly is because of the very high plate resistance of that tube. If the plate load is inductive, the low freqs are attenuated.
The Steampunk Scotty Regen came with three 80M Plug in coils (why 3?) one 40M coil and one 20M coil. As part of the restoration, I will do a 30M coil on a tube base just as an experiment.
Where might one get a deep dive on these throttling schematics broken down knife and fork style? (Volts for dolts method) Or tube radio topologies in general. Newbie here hence my curiosity 😉
A very commonly use negative resistance component, was used in the HP RC audio oscillators, developed in the late 1930s early 40's. This component you probably have guessed it by now, is the common 3 - 4 watt 115v night light bulb. It was use to control the negative feedback vs the frequency determining positive feedback, so you could get a clean low distortion sine wave output. Could this principle be applied to a RF regenerative circuit?
In commercial broadcast radio production, regenerative sets went away by the mid 1920's because the TRF and superheterodynes did not emit interference when you went into oscillation, and they were easier to adjust and tune for listeners. They lasted longer for the military longwave receivers up to WW2 and hams and experimenters built them well into the late 50's.
It really is hard to beat a twinplex with a 6SN7 or 12AU7, with a standard Armstrong setup and a 300 pF throttle cap. Build it as is with a fixed 2" form rather than plug in coil. Bottom Pri 10T, Top Tickler 30T, middle Secondary 90T. Then remove the 470 pF bypass cap and replace it with a throttle cap. www.frostburg.edu/personal/latta/ee/twinplex/schematic/twinplexschematic.html
Thank you for the link, I see your describing winding 3 separate coils on 1 form, is the Pri 10T for the antenna & ground? I don't like the the way that guys design uses a variable cap to couple to antenna directly to the tuning coil. BTW: I have a ton of 6SN7's NOS and UOS, good tube choice.@@MIKROWAVE1
The real true Inventor of the "Regenerative" radio Detector may never be known.....Anyone who's played around with "Hot" Non-Regenerative Grid Leak receivers pushing Higher plate voltage, using High Q Litz wire Coils & other High Performance Low loss Circuitry may have experienced sudden unexpected Uncontrollable Oscillation sounds when Tuning across the Band Not realizing much Weaker never heard before stations are Mixed in under the Hiss/squeal Regeneration sounds....Armstrong's novel Patened Idea of intentional Adjustable "Controlled Oscillating" detection mode may have been Accidentally noticed by Earlier radio Experimenters but considered it's effects as Undesirable & Unstable operation....Who Knows how many times in History a functional Receiver circuit was Overlooked because No transmitter was nearby ?? .....
Yes, it was an idea whose time had come, and I'm sure lots of people stumbled upon it but didn't realize its value. One of them may have been Lee de Forest.
@@amoore411 deForest, perfect example of wandering into great things! The tragedy is that after getting the patent, then they realize the errors - how they should have made the drawing easier to understand or more correct, but too late! They had to defend it as shown nevertheless, waving hands and finding notebooks and communications to back up claims. In the end all of this killed Armstrong.
