Super Regen Part 4

[@thomasvandevelde8157]

Damn, you're igniting an old love here! Gave up on Rushboxes because they're no longer competitive... According to those around me. I had them improved so they could detect narrowband FM and near the end I was playing with squelch but ran into the need for semiconductor-diodes and the lot. Now however, many subminis further, I think I'm get another shot at the whole NBFM-affair.

[@wadepatton2433]

THIS is Ham Radio. or it was when I got in and most of the OM's knew much of this stuff. Thanks for keeping radio alive as I recall the "neat old days" when men were men and built their own PS's ( I was Elmer'd through one myself.) 73

[@MIKROWAVE1]

Thanks. Playing with old stuff and getting as few shocks as possible!

[@blacksmock445]

The 88mH chokes were inserted into each wire of the underground telephone line at 2000 yard intervals. This was done to counteract the capacitance between the wires and obtain the 3kHz or so bandwidth required for telephone speech. The bandwidth could be improved by inserting 44mH chokes at 1000yard intervals. This "loading" as it was called was used in multi-pair telephone cables. Overhead telephone wires on poles with arms and insulators had a very wide bandwidth and comparatively low losses as long as the insulation resistance could be maintained at a high value. Something very similar was used as antenna feeders at short-wave transmitting stations.

[@RonanCantwell]

Fantastic results! Thanks for sharing your design process. I've really enjoyed this mini-series of videos.

[@MIKROWAVE1]

The key is to not start with all of the answers and let the circuit design itself. Taking Heathkits circuit was a short cut. I can not imagine what time and resources validating a kit for mass distribution must have taken in those days.

[@coltronex]

Enjoying this series of regen builds,keep up the good work!

[@MIKROWAVE1]

Thanks for watching and listening to the noise!

[@SpinStar1956]

Had to laugh: Earlier in the video, I was thinking that a noise-squelch would make listening to the aircraft band so much nicer; maybe to the point where you spring for the internal power supply components Hi-Hi! Great video Mike, really appreciate the circuit walk-throughs. 73...

[@MIKROWAVE1]

OK OK maybe we strap on a squelch. Should be enough noise!

[@thomasvandevelde8157]

Circuits like this exist with semiconductors, and older patents indicate it existed with tubes as well. Squelched super-regens were used professionally I suppose at some point in the 20s and 30s.

[@vincei4252]

Excellent. Thanks for the awesome full screen schematic. It always amazes me that communal garden vacuum tubes can work in the over 100MHz range. I'll be building one fore sure. It's funny, I just came from an Old Tech Guy video where he was decoding NOAA satellites on 137Mhz using SDR's, would be fun to do just that with tubes!

[@MIKROWAVE1]

My first sat reception on 137 MHz back in the early 1970's was with on an old surplus R-508 with a horrific noise figure and a ground plane on the roof. That thing had three pentodes like 6AK5s for the front end. But it worked!

[@paulphoad]

Actually, the self queching in done via c7 and c8 and the pot. As the circuit oscillates these build up a positive voltage at cathode and cut the tube off. Tube restarts osc once they have discharged. The choke and cap on plate are just 'rush' filters

[@MIKROWAVE1]

Very nice squegging explanation!

[@simplyflipflops]

Thank you Mike! Love it.

[@MIKROWAVE1]

Thanks for watching me play with this old stuff.

[@acestudioscouk-Ace-G0ACE]

Very interesting thanks Mike! A good first time out with the screen capture demo too! If you found a slightly larger mouse pointer in your junkbox it would be even better! ;-) LOL

[@MIKROWAVE1]

Can only improve. Ha. I will find a halo effect.

[@arildoaparecidocosta5729]

Ótimo vídeo trabalho gualidade total bazuka Foz do Iguaçu pr Brasil 🦈🦈🇧🇷🇧🇷🦈🦈

[@MIKROWAVE1]

Estou tentando aprender as novas técnicas de vídeo. Obrigado por assistir!

[@thomasreed325]

Great series!! thanks again

[@markholm7050]

I often wonder about the seemingly high noise and poor fidelity of aircraft and atc radio transmissions. Would they be better off with FM modulation rather than AM? Or perhaps even better, some modern digital modulation method?

[@MIKROWAVE1]

I was in an FAA facility using 1955 vintage analog character generator CRT equipment in the late 1990s to track all the planes. They finally replaced them with 400 MHz Motorola power PCs which they will use for the next 20 years. Let's just say things go slow. Next-gen which finally uses GPS and digital is still ramping.

[@_wave64_]

It would be quite a challenge to switch the entire aviation industry to FM or digital (including the tens of thousands of Cessnas and Pipers) - plus those aircraft that fly into the US airspace would also need to use the new system. AM has the advantage of fading gradually all the way down to the noise floor, whereas FM and digital cut off sharply.

Muy bueno Mike!!! José Luis-ea5bii

[@tubeDude48]

You didn't show it, but I assume V2 filament- Pins 4 & 5 is also connected to the same place as V1. --- Is L2 wound around R2?

[@MIKROWAVE1]

Couple of changes didn't get picked up in the fil after the modl. But yes.

[@tubeDude48]

@@MIKROWAVE1 - Thanks Mike!

[@MIKROWAVE1]

R2 is a resistor that is soldered across the coil to lower its Q and stabilize and broaden the response. The coil has a slug that can be peaked in the middle of the band.

[@gd2329j]

Mike i don't like the volume potentiometer arrangement . It moves the plate voltage !

[@MIKROWAVE1]

This is an old and fairly common hookup and old shortcut circuit story about saving a couple of parts. You get away with it, but yes, it is not best practice to mix DC and AC in controls. Another symptom is pot noise.

[@DAVIDGREGORYKERR]

A Slim-Jim antenna for 108-138 MHZ will work better, what about a SBR amplifier output stage

[@MIKROWAVE1]

Which reminds me of true antenna story. I was locked out of my vehicle a the end of a canoe trip and this Cuban guy helped me by getting into the car by bending my 108" whip over and Slim-Jimming the car open in one fluid motion.

[@_wave64_]

Wondering if "frekvencija" and "megaherc" are Croatian?

[@MIKROWAVE1]

Yes Just for effect!