Soviet radio restoration, explaining a superhet, ratio detector, AFC, IF, image frequency 

I love your "bloody-long" videos. Thanks!

47 minute long video? Consider me satisfied!

As my father said: the most hard and complex devices are Radios compared to TVs or anything else (in the old era) My father has some experience on Radio/Tv repair but he is no longer remembering most of tricks

Thank you for explaining the working of ratio detector circuit. I think I finally go the hang of it. That's bloody amazing ;)

Very nice explanation of these tuners, which work better than some of the ones we have in low-priced products today. My grandmother built super-het tuners for the U.S. Military in the 1950's/60's and tried to teach me how they worked, but I forgot virtually all of it by the time I reached adulthood as I was more interested in computers ;). Some parts of Europe have stopped FM analog broadcasts entirely, so analog radio receivers are becoming more and more obsolete, as analog TV tuners already are. AM survives, but more and more shortwave is becoming digital as well as it can use bandwidth so much more efficiently. This is generally a good thing, but with digital transmission you cannot simply build an electrical device that will receive intelligible signals; you also need digital "demodulation" to convert the signal to a useful form. There should always be a place for simple AM-modulated shortwave carrying voice or Morse as that remains useful even in an apocalypse ;). Most of the people that knew Morse are dead, though.

8:44 finally! A hungarian schematic on this channel!

Thanks for the nice explanation of how this receiver works! You really hit the sweet spot for me this time, where I know just enough to follow you, but not so much that there is little left to learn.

Thanks for a great explanation of the ratio detector - I finally understand it after all these years.... yay!

Again a great video, I always have a problem remembering the superhet, but I bet this time it's going to stick. Thanks a lot!

18:08 The sadness in his voice when it stopped working

Great video, thank you. Já jsem z Pardubic ale žijí v USA , škoda že my tady nemáme takové staré radio. Děkuji moc, hrozně moc jsem se naučil on tebe.

Very interesting video with the old soviet-radio! Thank you DGW! God bless you!!! 👏☺️

This video is actually great educational content. You explain things not just theoretically, but practically. Your other videos are equally good. Your channel deserves much more views.

DiodeGoneWild, I love your videos and have learned a lot about electronics from your videos. Wishing you a long and healthy life, greetings from the United Kingdom.

the best explanation ratio detector i ever seen in whole internet !! he is a genius

This is the best explanation of a ratio detector i have ever heard.

Thanks for the great explanation! I finally understood how a ratio detector works

In the model number of the Soviet receivers and other general purpose electronic the first digit indicates the complexity class of the receiver, which includes the minimum set of functions of the device, sensitivity and range of sound frequencies produced by the speaker. There are 4 classes in total: 0,1,2,3. Electronics that do not meet the requirements of this standard received a classification of 4,5,6 (as a rule, due to some worse parameters). The receiver "sokol" of the 3rd class model 08 is so called.

Very nicely explained as always, thank you!

Wow... I found your another channel...... Full of interesting & amazing videos 😍😍

Awesome explaining - thank you very much! (no minutes are to much)

Best video on this subject.

Looking forward to the second part!

you are doing the best job, thanks!

Thank you for the long Video. Gott mine today sheap from German Ebay, must be the Western Export Model up to 104 Mgz. It works ok on Fm and now i hesitate to tinker on it seeing how packed its inside.

very well explained! thank you!!

Nice explained.

Great video!

Great video, interested to see the regulator it's some sort of linear regulator i guess , second watch has me loving your explanation.

Nice lesson, thank you!

Nice and detailed! 👏 👏 👍

Superbe explanation

Very informative video, old analog radios are really black magic

Nicely Explained 👌👋

Awesome video!! In 46 minutes you have explained a whole radio from the antenna to the speaker in the clearest way possible! Just for curiosity, are you a teacher or is this just your passion?

Classic collection of the soviet radio issues.

Amazing video. The superhet and the filtering are still a bit of a haze to me, but this shed a lot of light. I only recently got into radio tech (even got myself an old VEF).

You always learn something here. I knew how a superhet works, but didn't know that sokol meant falcon in Russian although I know some people with Sokol as last name.

and now travel back in time to the designers of this radio and tell them we now have software defined radios .. they would have burned you at the stake 😂

I recently bought a new new small radio, Retekess R115, and that does cover the OIRT FM band, as well as the 76MHz FM band that's used in Japan.

Love Soviet erra engineering .

Finally Radio ...thank you.

I held this radio in my hands in 1998 year when I was 15.

A bloody great bloody long video and a excellent tutorial...cheers.

Much appreciated 👍

At 10'48" your radio received a station from my country, Romania. :)

I don't have time to watch this yet but I am very much looking forward to it, hahah. After that Soviet TV I want to see all the Soviet things!

Fantastic video as usually! I was thinking to a solution to convert it to modern fm reception without modify the original circuits (but you probably already now this solution...), you can use the local oscillator, feed it in a frequency to voltage converter and then feed this dc voltage in a small varicap radio reciver, and then inject the output in the audio amplifier, i saw this solution used in old vacuum tube radio restoration. Actually, there are already made kit for this. I was trying to do it on an old Geloso reciver from 1934, but i was trying to use scrap parts, like for the fm reciver there are those small Chinese poket radio with scan button instead of a tuning knob, feeding the varicap with a dc voltage from a potentiometer allows you to use it as a tuning knob (cheap radio and cheap hack!), meaby you already have this tipe of radio in your collection 😁 Would be nice to see a video with your idea and solution to make it work!

For a second i thought i was watching Shango066, but no sarcasm :) That radio looks well made, i also like the different design of components. Hand drawn pcb tracks, some people don't like them but they work fine :-D Some schematic diagrams are all over the place. Etch-a-sketch lol. I am used to a block of parts with inputs and outputs, no mad wandering off for no reason. Your cat would not make a messy diagram, unless it was made of string and a fake mouse :-D

Hi diode gone wild if you are reading this comment. Please next video explain a Solid state Geiger counter.... Using photodiode ..... Very Interesting. It works

Just for clarification: The frequency response of an ideal LC filter is inversely proportional to the frequency difference from resonance, but real LC filters have a round, wider, not infinitely high peak at resonance. The bandwidth is usually measured between points where the voltage drops to -3 dB below peak (1/√2̅ of max amplitude) or -20 dB below peak (1/10 of max amplitude).

10:46 that is romanian post radio. Interesting. 😅

In the US we had FM radio in a lower band before moving to the modern 88-108 MHz. Except this was a _long_ time ago and the old band was discontinued in 1949 so it was never popular.

Most likely 9V (Вольт) socket has center positive. Most Soviet radios had this arrangement. The old school transistors you are referring to most likely germanium (германиевые) transistors. Soviet made BM paper capacitors were very stable and could last tens of years. K50-6 soviet electrolitic capacitors unfortunately were notorious for leaks, though it is 1980..Capacitor you were referring to was a part of so called ARU (АРУ Автоматическая Регулировка Усиления) system which controlled automatically RF gain. On schematics transistors ГТ404Б (GT404B) can be replaced with 2SD127A, AC141 Спасибо за отличное видео.

As always very good and lot of animals...

sokol where the best radios. i still have a sokol 403 that still works without any modification ar replaced component

I had absolutely the same radio at home in Prizren...Kosovo and Metohija.....

I've been subscribed but I missed this video somehow. I noticed your video like 10 spots down in the sidebar after watching Altium Designer's channel.

Thanks for ur information .i hope u make video how to convert modified wave to pure sine wave we need it so much please

Dan where's the hotel vacation video ?😂 what switches and lamps. it's time for vacation 🎉🎉

There are some newer Chinese radios which can pick up the OIRT band. BTW OIRT stands for Organisation Internationale de Radiodiffusion et de Télévision. It was one of the predecessors of the European Broadcast Union.

Awesome ussr quality eletronics.

Thanks for the explanation. I am looking for a diagram to make a metal detector

Damm my guy teach me better than my teacher at school

Staré východní FM pásmo není opuštěné, nastěhovalo se tam vysílání bezdrátového místnbího rozhlasu. Jesli máš v okolí nějaký provozovaný bezdrátový rozhlas, můžeš ho zkusit na tom rádiu chytit.

Ahoj, mam sokola taky.......kdysi to byl darek od taty k vanocum.....hodne me bavilo....pak upadlo v zapomneni a zmizelo nekde na pude....nedavno ho tata nasel a dal mi ho....momentalne se pokousim preladit ho na CCIR.....zmenou kapacit v tabulce na schematu na hodnoty pro ccir pasmo....

OIRT wasn't "old" or "worse". Yes, it's no longer in use, but that's because in mid 90's there was more cheap sender equipment for CCIR (87.5 to 108) OIRT's lower frequency was better suited for the Soviet union's geography, and if I remember correctly, the bandwidth was better used, i.e. not the whole 100kHz as in CCIR, but ca. 38kHz + a gap - that's what you need for stereo transmission. And there was stereo for it since mid 70's.

Nice radio and nice explanation! Wondering if the voltage regulator has gone open circuit, according to the 4.2-ish volts voltage and the low current, you might be able to replace it with a TP4056. in that case, the TP4056 will work in the constant voltage mode, providing a regulated 4.2V voltage. there is also TP4057, which is a smaller, less capable (lower rated current) version of the 4056. You can botch it on the regulated voltage rail.

If you reverse the diodes the AFC should work for mirrorfrequencies, right? Greetings from the Netherlands.

I love your cat's comments! Hello kitty! You are very pretty / handsome!

16:58 Timestamp Any details about that pink transistor tester? How can it test the leakage of caps‘s? was under the impression that transistor testers didn’t put out anywhere near enough voltage to test electrolytic leakage. Any clarification would be much appreciated. Thank you for your time

Brother, could you please explain what is different between CCCV SM battery charger and a normal SMPS. Thanks.

09:56 it started fixing itself!😂

Is there a second part? I cant find it!!

I'm looking at the pcb and thinking how they made it. Hand drawn?

конденсаторы типа К50-6 и К50-16 надо менять сразу даже без проверки. почти всегда на этом ремонт заканчивается и устройство начинает исправно работать

Hezké

Interesting video.

20:50 that's what I was going to ask but your cat asked just after

And of course the cat is my favorite

Those weird ones are the old Hungarian symbols for electronic components. Later they were replaced to international ones. That schematic is made by Gelka (short for Gépipari Elektromos Karbantartó Vállalat, aka Mechanical Electrical Maintenance Company), a socialist company owned by the government. In the original form it existed from 1960 to 1993.

Probably can be tuned to the modern bands with just a turn or two removed from the input and LO inductors, or lower value padding capacitors for them. Then would cover the band, though simply taking the input filter and making it resonant ant the higher frequency without touching the LO would work, covering part of the band. Then getting AFC to work would just mean turning the 2 discriminator diodes around, to change the sense of the AFC voltage to suit the image reception.

That foreign station sounded like Romanian folk music

Did you mange to repair it? I couldnt find the next video.

Super😂🎉

Wonderful, does anyone know who discovered this differential mixing effect?

Keep making RF videos

Hi please can you make video about your lab bench power supply or make one of those please can you do that?

13:47, new allarm clock.

Can someone explain to me how I was able to receive 450MHz analog cellphone conversations with my OIRT band Panasonic RX-1650 mono boombox? They showed up around 69MHz on the dial, dozens of cellphone signals very close to each other, but the AFC was able to jump across them accurately, it needed a very faint and careful touch of the tuning knob. 450MHz is very far away from the FM band, maybe I was receiving some inter-tower link which used a lower frequency? There was a continuous weird buzz on the channels which were in standby, so I guess these signals were coming from the tower, and not from the phones, because a phone would not transmit continuously in standby. I still have a cassette with recorded conversations, from the late '90s. It even contains someone listening to his voicemail :-). Usually only one party was audible, the other was very low volume or completely inaudible.

Center positive / negative not mentioned.

All kind of sokol radio este sold in Romania in the ussr

I HAVE A QUESTION ON RUSSIAN RADIO SCHEMATICS. On most radio schematics the ground symbols shows that the chassis is negative but on Russian schematics the symbols are showing positive or b plus chassis. Is this true?

42:10 than you need another tool Spectrum Analyser And I like if you built this yourself

Try listening to SW in the night, u should receive more stations.

Devices are so scared of your huge soldering gun that they try to fix themselves.

I think you entered Shango066 territories! He should really see this, he loves that Russian stuff

20:44 where is the talkative Kitty ?

I had one of this radio, but the status of it was way unrepairable, so, sadly it got reused for salvaging components from it. 😐

I have a radio that can't hold its station. After a few minutes it drifts/weakens. I have to retune it higher up the band. Then a few minutes later, same thing. So the stations are all "Crawling" up the dial. It used work for years, its a modern radio. Confusing.