Your First Tube Radio Project

[@alasdair4161]

Interesting, I just remembered building a similar set as a kid in the 70's. It used a 1T4 that I recovered from a portable radio I brought home from the rubbish dump. I fondly remember there were old valve radios everywhere at our municipal dumps back then, my father would always curse me for bringing more 'junk' back home. Frequently they were just a chassis, the bakelite cases usually being smashed, but that portable had battery valves which to me were the holy grail, to be able to make something portable really was the ultimate challenge.. Cheers.

[@MIKROWAVE1]

Yeah those battery tube radios of the 50s were discarded pretty quickly when transistor radios came in!

[@DAVIDGREGORYKERR]

Using Wire Ended vacuum tubes like those used in hearing aids from the 50's you might be able to make a radio about the size of a cigarette packet.

[@jozefbubez6116]

By the end of WW2, some Polak radio engineers working in England did pretty much that!

[@jozefbubez6116]

Excellent presentation especially re: leaky-grid capacitors and resistors. As young lads back in the early 1960s we made quite a number of these without really understanding the effect on audio response. Likewise, regeneration would narrow the band-width but by how much? Having loud-speakers invariably without a baffle or cabinet of any kind, guess this gave the necessary HF lift as to us it sounded OK even with the 'pop' groups of the day. Keep up the good work! P.S. These days my ears act as 'brick-wall' low-pass filters cutting off at about 2 kHz!

[@RechargeableLithium]

Another cool receiver! My first one tube receiver was Elmer Osterhoudt's LW/MW/SW rig from Modern Radio Lab's HB-4. Bought the booklet in the mid 1970s, and finally built the receiver as a final exam project in a HS electronics class in 1981. It uses a 1Q5 ot 1C5 and is a very sensitive receiver. Band changes are via plug-in coils like your last series. Surprisingly, MRL is still around and still has high-Q coil forms available. I have parts in storage for another build when I get sailing out of my system and return to land. Thanks for the history and the receivers! 73, Andy aboard SV Jane Ann

[@MIKROWAVE1]

Don't be bingeing in the bilge! That sounds like a cool radio project and the 1Q5 octal is an old battery bottle from 1935 that was used in the second generation of portable gear including some jungle radios in WW2.

[@RechargeableLithium]

It was a fun project. I enjoy building QRP rigs, and have gotten comfortable with SMD parts. There's something physical and tactile about old tubes, tho. The size, the smell. Lovely! Thank you for your presentations!

[@ronnylucas8857]

This will be my first tube radio project! Thanks...

[@MIKROWAVE1]

Keep posting on your progress!

[@thomashowe855]

Mine too. As well as this, you inspired me to get a license. Thanks, and I consider you an Elmer!

[@MIKROWAVE1]

@@thomashowe855 WOO!

[@kennethandrysiak4130]

Thanks again, Mike. Always look forward to your next episode. Concerning this project, or any of the other receivers that were designed for BCB reception… back in the 80’s the FCC mandated that AM stations limited their ‘high end’ to around 9.5 kHz and then ‘brickwalled’ the response above that. AM Broadcast processors for US stations all incorporated what amounts to a 75 microsecond pre emphasis curve (like the FM stations) but with the steep rolloff as I mentioned. Without accounting for that, a crystal set, regen, or grid leak, may sound excessively ‘bright’ or harsh. That pre-emphasis could be addressed, in this case, by factoring that in to the grid leak resistor/capacitor makeup… or, could be addressed in the audio amplifier by incorporating a 75 microsecond de-emphasis circuit using an appropriate capacitor and resistor as a low pass filter. This would mellow out the audio. Regards, KC9NAN

[@MIKROWAVE1]

Some of them also have subcarrier data services inside the 10 kHz.

[@kennethandrysiak4130]

Can’t speak to the data services (I knew that existed; didn’t think it was used much)… but the hybrid digital (HD) standard dumps multiple ‘digital carriers’ within the audio passband and even outside the ‘channel’ (+/- 10 kHz) of the station. WBZ had been using this fraud technology for several years. All the Chicago stations that had tried it dropped it. Junk. Plus, you must limit your analog audio to 5 kHz (or less) so the analog doesn’t interfere with the digital carriers placed above 5 kHz. Your cellphone audio may be a better experience! My 14¢ (inflation).

[@JCWise-sf9ww]

@@MIKROWAVE1 IBOC HD AM radio signals, we had a local station that use to have the IBOC transmissions, but they turn it off. One issue I have with IBOC subcarrier data services, is it bleeds over into the adjacent AM stations only 10 kHz away, making DXing of some distance stations impossible.

[@JCWise-sf9ww]

@@kennethandrysiak4130 I agree with you the IBOC is useless on AM broadcast band. interferes with adjacent stations.

[@myvair]

Fine business Mike. I love watching these videos over and over. I learn something new every time. What I found especially interesting was the interplay of the grid leak capacitor and resistor values compared to the frequency bandwidth and the RF plate bypass capacitor value vs the audio response.

[@MIKROWAVE1]

When you only have a few parts, everything can be investigated!

[@francoisdastardly4405]

I really enjoy all your videos. Thanks !!

[@snarfusmaximus]

Very impressed by the performance. I own several 1920's TRF receivers and wasn't aware that a grid leak detector would work that well without several tuned stages before it. Looks like I'll have to whip one up and see how I go.

[@drontobil]

OK . Done. Used a DF91 instead, picked 2.2M for grid leak resistor. Used 4 tired 9V batteris (33V)and strangled the A+ battery to 1.35V. Soldered as much as possible on the tube holder and on ceramic stand offs. Fed this contraption with a 41 m long wire some 25 meter high with a single wire down lead. Magic! Some stations would benefit of a volume pot even with the antenna coil pulled away. Thanks for inspiring me! de SA3BOW

[@MIKROWAVE1]

Beautiful SA3BOW! Booming in signals!

[@drontobil]

@@MIKROWAVE1 Beautiful? To small photos on qrz to reveal the sloppiness then. Would this be a suitable radio to "upgrade" to a regenerative? de SA3BOW

[@Kysushanz]

As a young boy in the 1960's I made a Hikers One radio from an old Radio Magazine and it used a DL92A valve. I have never seen that valve referenced ever again! The little set was amazing but I found I could increase performance by winding up the voltage supplied to the valve until one day, it just gave out@! I had plans on trying to build a Hikers Three but never did.

[@Jeffrey314159]

I would say from my experiences that a grid-leak detector IS NOT very sensitive with antenna aerial length of just 50ft of wire. But many factors come into play here: the tube type, the antenna arrangement, the location

[@MIKROWAVE1]

Well I agree that it is not as good as the regen, but it is fairly close to a table radio, with a good antenna.

[@ingussilins6330]

Slide tunner is a "best part" :) Like a 1910's radio.

[@SpinStar1956]

Seemed to have good fidelity both for voice and CW; and easy to use without much refinements. Back in my day, transistors were all the rage so I built radios using them since tubes were really poo-poohed at that point. For a long time as a kid, I had stripped out many TV sets but then gave all my vacuum-tube stuff away; sure wish I had it back because I had everything including a half-gallon milk carton full of RF chokes (just hurts to even think about it!)! We filled this guys station-wagon, and it was nearly dragging the ground when he left! 73...

[@MIKROWAVE1]

Now that was a righteous Junk Box of parts!

[@Madness832]

Kudos for grabbin' Boston!

[@solarflare4259]

Great Video! It brings back memories.... I recently acquired an Aud-Ion battery powered tube radio. It has 4 tubes 1U6,1T4,1S5 and 3s4...None of them glow even if the heater on all of them is ok. Do these tubes usually visibly glow when 1.5V Dc is applied to the heater?

[@MIKROWAVE1]

It is like magic. You do see a dull glow in some of them in total darkness. They emit nicely at low power because they do not have to heat a cathode.

[@solarflare4259]

@@MIKROWAVE1 Thank you.! That explains everything; the heater is the cathode and I did not check in total darkness...

[@andrewandrosow4797]

Hello! It would be interesting --two tube superhet. There needs two coupled IF LC circuits. The second stage - regenerator on one tube.

[@MIKROWAVE1]

A reflexed 2 valve Superhet can be done all right. But it becomes a bit easier to sus with three tubes!

[@jansugalski4856]

Brilliant video. Thanks

[@MIKROWAVE1]

Thanks for watching!

[@albertodelrio9206]

Excelente video. El transformador interetapa, es el mismo que usaba con el regen anterior Morgan, con válvula 30 ?

[@MIKROWAVE1]

Si, el transformador es el mismo. Las mejores interestatales pueden tomar de 2 a 5K del detector hasta una alta impedancia de 5 a 50K. Este transformador no es ideal ya que es solo de 1K a 3K.

[@jansugalski4856]

I wondered if you have used the ARBE-III Universal Battery Eliminator for your projects and what you think about it. I found it useful for the old farm radios I have. Thanks

[@MIKROWAVE1]

Those little battery eliminators go all the way back to the beginning of radio. People hated batteries even then!

[@DestroyingTheLeader]

Hi Mike! I'm a total beginner with very high interest in starting building radios as a hobby. Would you be able to make a video of how to wire this all together, and how that would compare with the schematic you have shown? Anything helps. Thank you!

[@matthiaswilhelm9813]

Ich wickelte Wabenspulen😂❤dann starb der deutsche AM Radiofunk.das beste ist Spulenkopplung mit gutem Kopfhörer.Wird der Kreis nicht belastet,siehe Röhre,dann hat man saugute Trennschärfe.😂❤❤❤

[@MIKROWAVE1]

Was für eine schreckliche Sache, AM Broadcasting in Deutschland getötet zu haben. Was machen sie jetzt mit dem Spektrum?

[@anthonymokelkie9360]

Back in my young days built the grid leak with 6SN7 , i did get it to work but power supply always had a hum from the 5Y3 circuit. you need good regulation Dc or battery. selectivity was a problem too, big gun station always took up big part of the varible cap. i got shocked many times from old chassis was building , once electrolytic blew up my God I was lucky no lasting damage , my God, 12 years old working old basment. you know about selectivity though friend mine tried the Spider web coils. I think he had better Q with that.

[@MIKROWAVE1]

Yes the circuit really adds gain up front and much of that makes it sensitive to hum and microphonics. A good coil setup and that tap idea can help with selectivity, as does the loading coil.

[@davidcampbell6527]

Really enjoying these videos Mike. Where has your tie gone though? I am a Manchester man and I always wear a tie! Best regards.

[@MIKROWAVE1]

I am also a Manchester Man - Manchester NH here in New England.

[@DPhippsActual]

Sir, were can I buy a book to learn these things. It's been an interest for many decades. It's been forgotten about as life got busier. But now retired and your channel has restarted the interest. Thans in advance...

[@MIKROWAVE1]

Wow. Elements of Radio (1940s), Any ARRL handbook between 1940 and 1960, Any of the Alfred Morgan Radio books, Any of the old William I. Orr Handbooks. , A beginners Guide to Radio 1956.

[@DAVIDGREGORYKERR]

What modifying it to operate as a reflex radio.

[@t1d100]

I know nothing about radios, but I purchased all of the parts to build a crystal set, years ago. Just haven't built it - yet... I also have some 6J1 tubes. Again, I know nothing about these, either. But, might they do for this project?

[@MIKROWAVE1]

Those miniature 6J1 Pentodes are very high performance USSR era design, UHF RF valves, that of course work fine for lower frequency and audio as well. It would work with 6V to light it and 45V. No problem. The plate and screen would be tied together to form a Triode.

[@t1d100]

@@MIKROWAVE1 IIUC, there is one tube in the receiver and two in the amplifier... Would the 6J1 also be okay for the amplifier side? I am not looking for extreme volume. I just want to drive an 8 Ohm speaker, instead of wearing an earpiece. If the 6J1s are not appropriate, I do have a DIY LM386 audio amp that should work. Thank you.

[@MIKROWAVE1]

@@t1d100 Two 6J1 valves and an audio output transformer will have plenty of gain and likely more output power. Maybe a 1 Watt of audio. They may need a bit more voltage than the battery valves I used. Maybe 90V to 150V.

[@rksg2003]

Does the air capacitor need to be a clockwise rotation to be like a normal am radio? I noticed they sell Counter CW rotation also? thanks

[@MIKROWAVE1]

Ha! Yes the dial and designs were for one way or the other! Sometimes a dial string arrangement or gear system switched it again to the dial direction.

[@rksg2003]

@@MIKROWAVE1 which is standard tuning with no gear system?

[@leebiggers3358]

Hi there. I have a question. I have several old tubes, and would like to use them to make a one or two tube radio. My question is: where can I find a schematic for using a type 75 tube?

[@MIKROWAVE1]

The Type 75 is the granddaddy of the Triode Diode used as a detector. So it will work in ANY single or dual triode Regen circuit for instance using, 6AV6, 6AT6, 6BF6, 6C4, 6J5, 76, 30, or duals like 6SN7, 12AU7 and so on, as long as you respect the filament voltage. It is just a standard medium-High MU Triode. It would work fine in this if wired to match the data for the pins. www.bignick.net/Morgan_Radio/Radio_1.htm

[@JCWise-sf9ww]

Which video did you introduce or make the adjustable antenna tuning loading coil?

[@MIKROWAVE1]

Ah. That was back in a series on Crystal Radios a few years back!

[@JCWise-sf9ww]

@@MIKROWAVE1 I found the video where you made the antenna tuner for the Crystal radio. 8 years ago, "Crystal Radio Part 2".

[@brianbloom1799]

Is that a small Isolation transformer your using

[@MIKROWAVE1]

I sometimes use an audio transformer to load the crystal radios output and get it into an amp..

[@thomashowe855]

Can I make this circuit with a 1u4?

[@MIKROWAVE1]

Yes. No Problem with the 1U4.

[@jamescarpenter8311]

Hi Mike, I've seen an old tymie tube radio schematic in the Wikipedia article "reflex receiver " ; could you test out this circuit in a future project? ( on my video wishlist😀)

[@MIKROWAVE1]

Cool stuff that reflex approach. Basically you can make the single tube tube act as both an RF Detector, and Audio Amplifier as the basic circuit - BUT with real cleverness - an RF and IF and maybe an Oscillator too - all at the same time

[@UpinkProduction]

I love it good 👍

[@stanbrown915]

🤣🤣🤣 I'm not ready for this video yet...might as well be speaking Chinese 🤣🤣🤣 One day though

[@MIKROWAVE1]

Take a peek at some of my older videos on crystal sets! My hair is less grey.

[@la5984]

Where may I parts for it

[@MIKROWAVE1]

Old AM table radios can be mined for all of these parts.

[@sciencefollower]

APPRECIATED. IF WE USE FERRITE ROD ANTENNA INSTEAD OF LONG WIRE ANTENNA, WILL IT WORK PLEASE.

[@MIKROWAVE1]

A LARGE ferrite Rod or a 3 ft Frame with about 10 Turns as the tuned circuit will work on the AM Band for you indoor experimenter folks. I will show an example. We can not expect the same sensitivity, but worth a try for a video.

[@claycoates5056]

@@MIKROWAVE1 interesting

[@robertbruce7686]

This is heartwarming de G7JDZ

[@MIKROWAVE1]

Not as heartwarming as a hot 6L6 Transmitter!

[@W1RMD]

@@MIKROWAVE1 I love the gentle non Chinese led induced blue glow 6L6's emit with the lights out.

[@davidcampbell6527]

My guitar amplifier has a pair of 6L6 Valves!

[@pauloandrade243]

Olá Mikrowave 1é dos melhores ensinamentos sobre o travo para elevar o som em vez de uma valvula que eu assisto até os dias de hoje quem sabe até do futuro...

[@MIKROWAVE1]

Obrigado por assistir a rádio de feedback, amigo!

[@nahumgromov5099]

It look like regen radio is easy to make. But when I tried to make it at home via replacing 1.5M grid leak with a piece of wood and graphite my radio did not work)

[@MIKROWAVE1]

So it worked with the 1.5M? But did not when you substituted the home made resistor? Like Spock said - "This is not logical. The circuit must work." Try making the resistor with a different media like cardboard.

[@adilsafraz6934]

Now transistor using nor tubes..

[@MIKROWAVE1]

Should work with JFETS with very little changed.

[@wesleyvanderveen4226]

Show the Build I cant read electric pictures

[@MirlitronOne]

Five bucks for a crystal earpiece? It's scandalous. Glad I bought a few back in the 1980s!

[@MIKROWAVE1]

Hams are not cheap. Hams are not cheap. Say it with me.

[@ON5ALE-Alessio]

Why destroy a good radio and make it lost to history to build a primordial one. Instead go to ham markets and buy one variable cap for 2 usd. There are many experts and amateur to talk to in those markets.

[@G7VFY]

First G7VFY

[@davidcampbell6527]

Not quite

[@G7VFY]

@@davidcampbell6527 drat!Foiled again.

[@claycoates5056]

@@davidcampbell6527 You are working too hard just have FUN

[@davidcampbell6527]

​@@claycoates5056what on earth are you talking about? Stephen took the comment with good grace in the fun that was intended. Perhaps you should too. A bit of decorum and punctuation wouldn't go amiss either.

[@claycoates5056]

@@davidcampbell6527 Understand just Have fun maybe you are thinking too hard thank you for the come back

[@dampandrew]

Big waste of time and effort 2 tubes are louder

[@MIKROWAVE1]

I have just received this week (from a viewer) an automatic regen to evaluate. It has 10 Bipolar transistors, 2 FETs, and two Quad op amps, and it does not even include the speaker amp. Wait till you see this thing.