2 Tube FM radio kit from Aliexpress

[@eugenepohjola258]

Howdy. Looks like a Colpitts regenerative detector to me. In my mind not a super regen. John Hunter from Cool Australian Vintage pointed out to me that managing regeneration by controlling the anode voltage produces inferior sensitivity. I suggest You feed full voltage to the anode resistor and manage regeneration by controlling the screen grid voltage. Best regards.

[@cool386vintagetechnology6]

Yes, it is a Colpitts oscillator, but it will super-regenerate because of the long time constant of the grid circuit.

[@eugenepohjola258]

@@cool386vintagetechnology6 Howdy. Aha, Ok. Living is learning. Thanks for the info. Regards.

[@MichaelBeeny]

It's basically a 1 valve radio. It's simply does not have enough gain to work. The second valve is just an audio amplifier, it's not even an audio valve. Being VHF you should not need a long wire arial. More like about 1 meter. Might work if you are VERY close to the transmitter but otherwise it's just a nice paper weight.

[@iceberg789]

right. need couple more tubes.

[@grzesiek1x]

It looks like to me that they copy some circuits without any insight or knowledge what they are doing and this is why it is a disaster (the same with lm317 kit that they still sell it and there are some errors in the circuit hahah ).

[@Impulse_Photography]

Maybe that 30 ft antenna needs to be wound to be effective - or maybe a Dipole or Loop fashion may help in this case.

[@uveprom]

I made modifications in it and now is a good amplifier… it works great like amp … quit the coils and variable cap and place audio Input there …

[@marc7637]

4 a5 tour sur L1 et 3 tour sur L2 ne donne pas la bande 88 à 108 Mhz mais plutôt 250 Mhz Il faut au minimum 8 spires pour L1

[@michelvansimaeys6586]

I also have difficultés to see where the typical feedbackloop is injecting in this circuit…

[@michelvansimaeys6586]

Hello Guys, i also bought this kit and guess what, it does’´t functions eitjes. Although the amplifier does a good job… I connected a function generator to pin one an the soundtrack was nicely amplified. Question is, how could the input circuit be adapted to make this thing functionning? We could keep the tubes and transformers. Any suggestions ?

[@franklinyoutubehu2349]

I would have to say that maybe if you hook two of these together, that you might get enough amplification to make it useful. Or you could try a really big antenna and a solid ground.

[@MichaelBeeny]

@@franklinyoutubehu2349 The frequency you are tuning would dictate the arial length. A long wire is great for SW but not VHF. The RF circuit simply does not have enough gain.

[@marc7637]

Combien de tour fait la bobine L1 et L2 le diamètre du fil et le diamètre de chaque bobine merci

[@franklinthu]

The coils had 2 and 3 turns, about 1/2 inch diameter. It's amazing that is all it takes to receive the FM signal. Still not sure how that works considering the coils worked best just being loosely next to each other and not nested together like a transformer.

[@cleangoblin2021]

Tube radios sounds really interesting. Thanks

[@muhammadrafique3903]

Very Good information videos thanks sir ❤❤❤Rafique mastoi DG Khan Pakistan 🏝🇵🇰

[@NilldoportelaPortela]

Parabéns meu amigo bacana esquema ??

[@readmedottext]

this was really interesting. I like you fix to get it really working.

[@KartikPatel-nt4ff]

😅😅😅well information good show 😅

[@perfeitobr]

LIKE 👍 BRAZIL

[@hobbyrob313]

what a waste of everything you had and did there!

[@grzesiek1x]

Chinese kits are very annoying ! Always , ALWAYS there is something fuc... up really!! And now it costs almost 40 $ hahahha Chinese don't want or can't learn on mistakes really. They sell the same crap over and over again and they don't even try to improve it or anything which always makes me wonder why... it could be a really great kit if improved a little bit, adding a good instruction and checked by someone with RF knowledge etc. It is just a waste of money really. Fu.. Chinese crap. I stopped buying from China apart from very simple things that I know will always work, like some cables maybe or something like that and straight from the original factory at least.