I just went the other direction and and mounted several different (actual) crystals for use with a cat whisker detector. I use galena, pyrite, and a sulfur oxide crystal. My crystal set receives from the broadcast band up through 6MHz via a 2 inch coil with 85 turns of #26 wire, tapped in 12 evenly spaced spots across the band. A set of Cannon hi-impedane head phones, an antenna tuner, and a double wave trap round out the set. People think I have a battery hidden somewhere. Thanks for all of your videos!!! I'm now restoring my Heathkit HR-10B using your videos as the basis of all my work... THANKS!!!
7:49 another reasons, and i think is the most important, is the recovery time and the capacitance. Two fundamental factors to be a good high frequency detector. Sorry for my bad english. I love your videos. Thanks from Argentina !
Mucha gente juega con los parámetros de carga de audio e incluso usa transformadores para optimizar el nivel de salida y la calidad del sonido. Gracias por ver este video.
Some years ago, I picked up some miniature wire-ended valves at Dayton Hamvention dirt cheap (no data, of course). Turned out they were mil-spec dual diodes, so last year in the throes of lockdown I started to experiment with them. They worked pretty well with my high-performance crystal set. Now I have more ideas to try! Thanks, Mike.
An EMP-proof radio has a bag of spare parts. Thanks for showing me how to eliminate sneak paths. That is a timely item to address. Of course, the transmitter has to be EMP-proof as well.
I'm attempting to use a dual filament light bulb as a tube and diode and use one to also transmit rf and use it for a valve on a tank circuit... I understand high voltage is involved and would love to see more videos like this
Cars may be pretty EMP proof now, but when the first electronic ignitions came out for cars we did an EMP demo for some military brass at the company I worked for. We dumped a larger than 1 ton, high Q capacitor bank into a pair of elevated irrigation pipes and measured the field intensity on a sphere hung between them. But we had the military brass park their cars just outside the fence 30 feet way from the test setup. They sat there in the research shed looking at the graphs and nodding distractedly, then they shook hands all around and left. Or they tried to leave. None of their cars would start after the test EMP. When the scientists suggested that perhaps their car's ignitions had a problem with EMP, we got their full attention. :)
This was a real problem before proper shielding and grounding went into vehicles. Semiconductor devices for cars are protected better now too. Modern cars have so many processors onboard that a "limp mode" is required to get you home after a failure. EVs should greatly simplify this part count. So much is devoted to emissions now.
Very interesting circuit going back to the basics of radio reception/AM detection. Very good results by the way and properly explained, my compliments & subscribed 11 march 2022.
The tube acts as the detection diode here and the other diodes act as varicaps (varactors) and are not parallelled. And of course you can switch 2 diodes in parallel, the one with the lowest barrier voltage will open first. @@Kangsteri
@@radiofun232 Yes. I think it has to do with the frequency and partially cause of the momentum of the flow. So it helps with very low wattage applications.
Neon lamp or any other discharge device is too slow to protect from EMP. You need to use TVSS diodes or MOVs to protect the circuit. Gas and spark discharge devices are sufficient for lightning induced surges. This was determined with ARRL research from the 1980s. Additionally, for protection of EMP from the AC power lines a standard MOV surge protector (the regular cheap ones) will clamp the EMP surge.
Hi Mike, I have watched a lot of your videos now some many times. Your knowledge is stunning definitely sparing me on to do some more construction. I do like that Watkins Johnson receiver. Not looking easy to get one. and R390 would also be good but getting one into Canada would be a problem due to the weight and shipping problems. The only others i have are a TS530SP, K3 and FRG7. Ok but not in the same class as that receiver. Just brilliant and thank you so much.
Receivers that use expensive parts and software are only "better" in some pretty rare corner cases. The Japanese won by utilizing many cheaper COTS parts and giving fantastic value and many more features at a reasonable price.
@@MIKROWAVE1 Thankyou for the reply. I was really after that S meter. However I can check the K3 and probably find out how accurate it is. I also rather liked your millivolt RMS meter. Going to have a go at winding some basket weave or pie RF chokes as these seem to be difficult to obtain. I tried my cheap CNC winder and to looks like it might work. The IF coils I wound on my old winder for a 1934 Sparton Radio I am working on worked fine. I had to make the spools as well as wind the coils. The old ones were just wound on wood dowels. Just pile wound so the Q would not be as good probably.
Интересны опыты с литцендратом (его нетрудно делать в наше время). Форма и размер каркаса катушки тоже исследовались... И с отдельными регулировками связи со стороны антенны и детектора, там можно кое-что "выжать", - это классика жанра 1930 -50гг. Цепь "земли" тоже достойна внимания. Спасибо!
Hello Mr. Mikrowave, This new video was interesting how to add protect to a radio that needs an outside antenna. Have you experimented with free power one transistor germanium radio? Its basically a crystal radio with an amplifying germanium detector transistor that takes the place of the detector diode. The base emitter junction is the detector and collector is output to phones. It gets it's power from another tuned antenna that is detecting and filtering a strong signal. Any strong signal that can be rectified into DC and have enough voltage to operate a small amplifying germanium transistor. An ECG 126 is a good choice. Then weak signals can come in better. I forgot what its called I think if I remember correctly its called a rectenna power supply. I have plans to build one strong enough to drive a 2" speaker and make a whisper quiet free power radio that I can put on my headboard at night and go to sleep listening to it. I live about 20 miles from a 50,000watt AM station and it might be enough. I don't know if the same antenna can be used for the receiver and rectenna power if so it will have to have some sort of filter splitter. I think it would be difficult to design and engineer and very challenging to get working efficiently enough for a speaker that has an impedance matching transformer due to transformer losses. It would need a 5000ohm speaker
Here comes the supper conductor diode out of mike's junk drawer. Need to use up that liquid nitrogen around the house. Now that clear channel from mexico comes in like gang busters. Best Regards Jack Hreha.
Good choice of catchy title with current events, lol. Of course the sun can do a pretty thorough job on us too, the power line transformers love to be DC biased from a geomagnetic storm. Kinda a endless list of stuff that can be broken. Of course crystal radios would be a lot better after most QRM is removed, lol. If you really want to make a post apocalyptic radio, I'd like to see you build a radio with flame diodes and triodes. I've thought about this a little, or maybe a lot actually, lol. Get an Aladdin Mantle lamp and replaced the mantle with fine thoriated tungsten wire, this gives you a cathode. Might be able to divide it into several sections for multiple elements. Of and they used to sell thermopiles for the chimminies to get a B+. I don't know why I lay in bed at night and come up with this stuff, and medications available? Interesting video as always, thanks Mike!
Back about 50 years ago tires were not conductive at all. It was common to have a "grounding strap" hanging from the bottom of the car to bleed off the charge accumulated by the friction of air passing over the body of the car. Modern tires have carbon added to the rubber to provide a path to ground. I have never tried it but you would probably need a megger to measure the resistance of a car tire. So car tires do provide a path to ground but I doubt it would make a difference in the event of a lightning strike or EMP. Side note: Airplanes survive lightning strikes all the time. The airplane that dropped the atomic bomb on Hiroshima survived the EMP.
Thank you... always fun. A couple comments: 1) when you were swapping out the tube detector for the solid state diode, I thought I heard an absence of electrostatic noise when the tube was in circuit... I know I definitely heard the crackling noise with the solid state device. I need to go back and listen again. If true, why would that be? 2) in the tube diode circuit where there is detection of the negative side of the envelope... if that is what is happening, AM stations must limit negative modulation to be never more than 100%. But they can modulation in the positive direction (and most do) up to 125% here in the US. So, the recovered audio would be a bit louder if one was using a detection diode oriented to recover the positive going excursions. Am I thinking correctly?
The commercials trick! Play normal station programming at just below 100% and then when the commercials come on boost to 125%! Wake up the sleeping people!
The commercials trick is one thing. The logic on demodulation the bottom or the top of the signal isn't quite correct. You can't go under 0% modulation as that would be a 180 degree out of phase signal, which would as you say detract from the total of the envelope. But the 0% negative modulation is just zero signal, and the 125% positive increases the peaks higher. So that only increases the change in V peaks, the top and bottom of the sine wave is still symmetrical. If I understood the question, and my answer was clear.
@@clytle374 Yes, I see my error. The peaks are identical on either ‘side’ (top/bottom) of the wave; yes, amplitude modulation wise, you can’t exceed zero % negative modulation... that ‘pinches’ the carrier off. So from Mike’s example of 1930s style detection... it makes no difference which way your diode is oriented to detect the audio as the RF envelope is symmetrically modulated by the audio signal.
Wow! All good thoughtful points. But we can flip the phase in many ways to get the right part of the modulation demodulated. Like swapping the antenna and ground leads.
The radio on wooden plank reminds me of a DIY trench radio in a book. It had a pencil graphite contacting a vintage razor blade for the detector, all assembled on a wooden plank. The had a title "Electricity for Recreation" OR something along the sames lines. Wonder if someone owns this book or remembers the exact title, author and publication of this book. One of the books in my dad's collection. Have been looking for this book for quite a while, having lost it in my school, way back in 1976.
Maybe I'm missing something but I thought to get EMP damage the circuit needed to be in operation . When I leave my radio desk I unplug both antenna and ground so any reception wood be minimal . If the pulse is that strong I think we'd get cooked too .
I have not heard this but you can argue about whether the device is drawing current with devices in the active region? or if the on-off switch somehow disconnects you from the line (which many do not now).
I am wanting to do crystal radios again for my physics students. To save money, would ferrite cores be helpful. The cost of wire is an issue as I have a lot of students this year.
You will end up spending more on the Ferrite Adjustable Coils or Rods. A pound of #26 AWG is about 1200 feet of wire and that would be maybe 25 or 30 bucks. Each student might need 25 feet of wire to wind the coils on a normal 1.5 to 2 Inch diameter cardboard tube.
Wow! The possibility of static buildup and snap! or a close lightning hit, or heaven forbid, a direct hit, is real. Best to disconnect and ground the antenna when not in use.
Are there any crystal sets for FM radio? I imagine it would be a bit more complicated. It would be interesting to see a build on one. Also, there's not really anything interesting to listen to on AM unless you like religious programming and politics.
Just a little 5 turn spaced coil wound BIC pen diameter and a 35 pF trimmer cap, a BAT-85 diode or 1N82 a .01uF cap and a 100K resistor and a crystal earpiece and a couple turns for a primary feeding some 300 Ohm twinlead into a 5 ft FM folded dipole. It works by slope detection.
The diode used in old TV tuner mixers was a 1N82 UHF germanium diode. You could make a dandy FM crystal Radio with one of those, a little coil, trimmer , cap and a crystal earpiece.
I just went the other direction and and mounted several different (actual) crystals for use with a cat whisker detector. I use galena, pyrite, and a sulfur oxide crystal. My crystal set receives from the broadcast band up through 6MHz via a 2 inch coil with 85 turns of #26 wire, tapped in 12 evenly spaced spots across the band. A set of Cannon hi-impedane head phones, an antenna tuner, and a double wave trap round out the set. People think I have a battery hidden somewhere. Thanks for all of your videos!!! I'm now restoring my Heathkit HR-10B using your videos as the basis of all my work... THANKS!!!
I said "band" when I meant "coil." Sorry about that...
7:49 another reasons, and i think is the most important, is the recovery time and the capacitance. Two fundamental factors to be a good high frequency detector. Sorry for my bad english. I love your videos. Thanks from Argentina !
Mucha gente juega con los parámetros de carga de audio e incluso usa transformadores para optimizar el nivel de salida y la calidad del sonido. Gracias por ver este video.
Some years ago, I picked up some miniature wire-ended valves at Dayton Hamvention dirt cheap (no data, of course). Turned out they were mil-spec dual diodes, so last year in the throes of lockdown I started to experiment with them. They worked pretty well with my high-performance crystal set. Now I have more ideas to try! Thanks, Mike.
I have some odd looking microwave valves as well to find a use for - and some scary ones with radioactive symbols on them!
One good thing about the crystal radio is that we can build another pretty quickly.
I wouldn't have thought of using a valve diode, but it certainly works. Thanks for showing that it does work.
You might try a UHF triode or diode such as 2C40, 2C42, 2C43. These have extremely close electrode spacing so the voltage drop is almost non existent.
SETI Crystal SET
An EMP-proof radio has a bag of spare parts.
Thanks for showing me how to eliminate sneak paths.
That is a timely item to address.
Of course, the transmitter has to be EMP-proof as well.
I bow to your spare parts! A big healthy junk box solves all problems.
One great thing about using a germanium/silicon diode is no external power required. Thank you for uploading!
The core of the crystal set mystique is no power needed!
The crystal radio is all new to .iv built two so far the last few months and on my third lol. Iv got good stuff coming in the mail and cant wait.
Building these things can become a problem! Don't make us have to set up an intervention.
Reminds me of Richard Dreyfuss in his truck in "Close Encounters of the Third Kind".... It definitely disabled him. ,🤣
Roy Neary : Just close your eyes and hold your breath and everything will turn real pretty.
I'm attempting to use a dual filament light bulb as a tube and diode and use one to also transmit rf and use it for a valve on a tank circuit... I understand high voltage is involved and would love to see more videos like this
Cars may be pretty EMP proof now, but when the first electronic ignitions came out for cars we did an EMP demo for some military brass at the company I worked for. We dumped a larger than 1 ton, high Q capacitor bank into a pair of elevated irrigation pipes and measured the field intensity on a sphere hung between them. But we had the military brass park their cars just outside the fence 30 feet way from the test setup. They sat there in the research shed looking at the graphs and nodding distractedly, then they shook hands all around and left. Or they tried to leave. None of their cars would start after the test EMP. When the scientists suggested that perhaps their car's ignitions had a problem with EMP, we got their full attention. :)
This was a real problem before proper shielding and grounding went into vehicles. Semiconductor devices for cars are protected better now too. Modern cars have so many processors onboard that a "limp mode" is required to get you home after a failure. EVs should greatly simplify this part count. So much is devoted to emissions now.
Very interesting circuit going back to the basics of radio reception/AM detection. Very good results by the way and properly explained, my compliments & subscribed 11 march 2022.
radiofun is fun!
I thought you said it's impossible to use two diodes in parallel :D
The tube acts as the detection diode here and the other diodes act as varicaps (varactors) and are not parallelled. And of course you can switch 2 diodes in parallel, the one with the lowest barrier voltage will open first. @@Kangsteri
@@radiofun232 Yes. I think it has to do with the frequency and partially cause of the momentum of the flow. So it helps with very low wattage applications.
Great video. I always wondered how the vacuum tube detector would compare to a germanium diode.
Well somebody had to redo this. I am sure many have tried it before me!
Neon lamp or any other discharge device is too slow to protect from EMP. You need to use TVSS diodes or MOVs to protect the circuit. Gas and spark discharge devices are sufficient for lightning induced surges. This was determined with ARRL research from the 1980s. Additionally, for protection of EMP from the AC power lines a standard MOV surge protector (the regular cheap ones) will clamp the EMP surge.
Very nice John. Good info for the builders!
Mikrowave your Emp proof crystal set is cool
Hi Mike, I have watched a lot of your videos now some many times. Your knowledge is stunning definitely sparing me on to do some more construction. I do like that Watkins Johnson receiver. Not looking easy to get one. and R390 would also be good but getting one into Canada would be a problem due to the weight and shipping problems. The only others i have are a TS530SP, K3 and FRG7. Ok but not in the same class as that receiver. Just brilliant and thank you so much.
Receivers that use expensive parts and software are only "better" in some pretty rare corner cases. The Japanese won by utilizing many cheaper COTS parts and giving fantastic value and many more features at a reasonable price.
@@MIKROWAVE1 Thankyou for the reply. I was really after that S meter. However I can check the K3 and probably find out how accurate it is. I also rather liked your millivolt RMS meter. Going to have a go at winding some basket weave or pie RF chokes as these seem to be difficult to obtain. I tried my cheap CNC winder and to looks like it might work. The IF coils I wound on my old winder for a 1934 Sparton Radio I am working on worked fine. I had to make the spools as well as wind the coils. The old ones were just wound on wood dowels. Just pile wound so the Q would not be as good probably.
Интересны опыты с литцендратом (его нетрудно делать в наше время). Форма и размер каркаса катушки тоже исследовались... И с отдельными регулировками связи со стороны антенны и детектора, там можно кое-что "выжать", - это классика жанра 1930 -50гг. Цепь "земли" тоже достойна внимания. Спасибо!
Hello Mr. Mikrowave,
This new video was interesting how to add protect to a radio that needs an outside antenna. Have you experimented with free power one transistor germanium radio? Its basically a crystal radio with an amplifying germanium detector transistor that takes the place of the detector diode. The base emitter junction is the detector and collector is output to phones. It gets it's power from another tuned antenna that is detecting and filtering a strong signal. Any strong signal that can be rectified into DC and have enough voltage to operate a small amplifying germanium transistor. An ECG 126 is a good choice. Then weak signals can come in better. I forgot what its called I think if I remember correctly its called a rectenna power supply. I have plans to build one strong enough to drive a 2" speaker and make a whisper quiet free power radio that I can put on my headboard at night and go to sleep listening to it. I live about 20 miles from a 50,000watt AM station and it might be enough. I don't know if the same antenna can be used for the receiver and rectenna power if so it will have to have some sort of filter splitter. I think it would be difficult to design and engineer and very challenging to get working efficiently enough for a speaker that has an impedance matching transformer due to transformer losses. It would need a 5000ohm speaker
This is practical in many areas with a strong local station!
@@MIKROWAVE1 This sounds like a fun aside to your Crystal radios. I'd love to see you build one or several of these types. Build it, Mike!
Here comes the supper conductor diode out of mike's junk drawer. Need
to use up that liquid nitrogen around the house. Now that clear channel from mexico comes in like gang busters. Best Regards Jack Hreha.
My junk box runneth over and I tread on many sharp parts!
Instant subscription!!!
A crystal set is what I would probably use after an EMP, because everything else has transistors an ICs.
A transistor is basically a couple of diodes. The tube diode is more likely to survive brute force of an emp.
very interesting Mike
Thanks for watching!
Good choice of catchy title with current events, lol. Of course the sun can do a pretty thorough job on us too, the power line transformers love to be DC biased from a geomagnetic storm. Kinda a endless list of stuff that can be broken. Of course crystal radios would be a lot better after most QRM is removed, lol. If you really want to make a post apocalyptic radio, I'd like to see you build a radio with flame diodes and triodes. I've thought about this a little, or maybe a lot actually, lol. Get an Aladdin Mantle lamp and replaced the mantle with fine thoriated tungsten wire, this gives you a cathode. Might be able to divide it into several sections for multiple elements. Of and they used to sell thermopiles for the chimminies to get a B+. I don't know why I lay in bed at night and come up with this stuff, and medications available? Interesting video as always, thanks Mike!
Holy Hornswaggles! Oh there are some of us that count valves rather than sheep all right.
@@MIKROWAVE1 lol, just a thought
What about using a Nuvistor tube as a RF Preamp.
I love those things - maybe dig up a socket.
Cars: I get the cage, but what about the grounding of the cage? Are those tyres conductive?
Back about 50 years ago tires were not conductive at all. It was common to have a "grounding strap" hanging from the bottom of the car to bleed off the charge accumulated by the friction of air passing over the body of the car. Modern tires have carbon added to the rubber to provide a path to ground. I have never tried it but you would probably need a megger to measure the resistance of a car tire. So car tires do provide a path to ground but I doubt it would make a difference in the event of a lightning strike or EMP. Side note: Airplanes survive lightning strikes all the time. The airplane that dropped the atomic bomb on Hiroshima survived the EMP.
@@jamesmoffat9754 I remember reading that early F15s had mechanical flight computers to ensure they would survive nearby detonations.
Thank you... always fun. A couple comments: 1) when you were swapping out the tube detector for the solid state diode, I thought I heard an absence of electrostatic noise when the tube was in circuit... I know I definitely heard the crackling noise with the solid state device. I need to go back and listen again. If true, why would that be? 2) in the tube diode circuit where there is detection of the negative side of the envelope... if that is what is happening, AM stations must limit negative modulation to be never more than 100%. But they can modulation in the positive direction (and most do) up to 125% here in the US. So, the recovered audio would be a bit louder if one was using a detection diode oriented to recover the positive going excursions. Am I thinking correctly?
The commercials trick! Play normal station programming at just below 100% and then when the commercials come on boost to 125%! Wake up the sleeping people!
The commercials trick is one thing. The logic on demodulation the bottom or the top of the signal isn't quite correct. You can't go under 0% modulation as that would be a 180 degree out of phase signal, which would as you say detract from the total of the envelope. But the 0% negative modulation is just zero signal, and the 125% positive increases the peaks higher. So that only increases the change in V peaks, the top and bottom of the sine wave is still symmetrical. If I understood the question, and my answer was clear.
@@clytle374 Yes, I see my error. The peaks are identical on either ‘side’ (top/bottom) of the wave; yes, amplitude modulation wise, you can’t exceed zero % negative modulation... that ‘pinches’ the carrier off. So from Mike’s example of 1930s style detection... it makes no difference which way your diode is oriented to detect the audio as the RF envelope is symmetrically modulated by the audio signal.
Wow! All good thoughtful points. But we can flip the phase in many ways to get the right part of the modulation demodulated. Like swapping the antenna and ground leads.
I have a 2C39 RCA UHF 2GHz mw tube and a LD942/13V66 13GHz capable NEC tube new from a TVL1003 tv relay mw link...
The radio on wooden plank reminds me of a DIY trench radio in a book. It had a pencil graphite contacting a vintage razor blade for the detector, all assembled on a wooden plank. The had a title "Electricity for Recreation" OR something along the sames lines. Wonder if someone owns this book or remembers the exact title, author and publication of this book. One of the books in my dad's collection. Have been looking for this book for quite a while, having lost it in my school, way back in 1976.
I think Mike would know. Hopefully he does and can give you the answer. I'd look for "Foxhole Crystal Radio."
@@johnnytacokleinschmidt515 Thanks John, hope so
Do I have to dig up the yard and get an old fashioned razor?
IN34 , AA117 GERMANIUM DIODES CAN BE ?
Maybe I'm missing something but I thought to get EMP damage the circuit needed to be in operation . When I leave my radio desk I unplug both antenna and ground so any reception wood be minimal . If the pulse is that strong I think we'd get cooked too .
I have not heard this but you can argue about whether the device is drawing current with devices in the active region? or if the on-off switch somehow disconnects you from the line (which many do not now).
I am wanting to do crystal radios again for my physics students. To save money, would ferrite cores be helpful. The cost of wire is an issue as I have a lot of students this year.
You will end up spending more on the Ferrite Adjustable Coils or Rods. A pound of #26 AWG is about 1200 feet of wire and that would be maybe 25 or 30 bucks. Each student might need 25 feet of wire to wind the coils on a normal 1.5 to 2 Inch diameter cardboard tube.
Hello Mike , what about an infinite impedance detector?
Less loading and perhaps more voltage to the headphones!
Try LED with DC bias...
Could work!
I had a very unlucky time where i leaved my cristal set connected all nigth on a storm the damn thing just catched fire
Wow! The possibility of static buildup and snap! or a close lightning hit, or heaven forbid, a direct hit, is real. Best to disconnect and ground the antenna when not in use.
Are there any crystal sets for FM radio? I imagine it would be a bit more complicated. It would be interesting to see a build on one. Also, there's not really anything interesting to listen to on AM unless you like religious programming and politics.
Just a little 5 turn spaced coil wound BIC pen diameter and a 35 pF trimmer cap, a BAT-85 diode or 1N82 a .01uF cap and a 100K resistor and a crystal earpiece and a couple turns for a primary feeding some 300 Ohm twinlead into a 5 ft FM folded dipole. It works by slope detection.
The Varicap sinthony it ' s OK.
Radio Tuning funziona molto bene con i varactor.
👍👍👍👍👍
Emp ?
Are the local am transmitters EMP proof ?
Will you have anything to listen to. If this happens ??
Most of them are messed up now before the EMP! Nobody pays much attention to the signal quality since its all talk radio now anyway.
Why not make some FM radios with a crystal .
The diode used in old TV tuner mixers was a 1N82 UHF germanium diode. You could make a dandy FM crystal Radio with one of those, a little coil, trimmer , cap and a crystal earpiece.
@@MIKROWAVE1 Slope detection, right?
Time. Killer.....waste time
ipocrit
vinovat conform acuzației, dar bine intenționat.
👍👍👍