Crystal Sets - Admittedly Biased

What about diodes? Which work best in crystal sets? Also: Sorry about the audio issue in the Diode Physics bridging video I made while travelling with a simple Microsoft app in Windows 10. It was not giving me any real control to boost the audio levels.I took it down.

[@MatthewBerginGarage]

I haven't thought of crystal radios since I built one when I was 7 1/2 years old. I used a circuit from a book called The Boy Engineer that my mother had bought for me in 1960 when I was 2. I even constructed a small single tube amplifier for it from the same book as well. Thanks for reminding me of a very good time.

[@farish5796]

OK, 51 years as an active Ham and you got me hooked back on Crystals Sets. Great videos and a lot of fun. Keep the videos coming. Tnx !

[@MIKROWAVE1]

Have fun and remember - it's all about the antenna. A longwire between 75 and 120 ft and a tapped antenna loading coil work wonders for the broadcast band.

[@joebidet2050]

Me too faris Ham 43 years 160m cw op Got recommended crystal radio videos On KZbin and now I'm hooked Send help 😆

[@ktheis1]

This is something I wanted to try myself but never had the time. Thanks for doing this!

[@mikesmuseum]

This was a great video, very informative. It's nice to see Alfred Morgan's book here and there. Thanks!

[@glenngoodale1709]

👍 Another great video. I wish more of the others who make these style videos had your gift of video production and narrative skills

[@Karl63601]

I'm really loving this series. Thanks so much.

[@acestudioscouk-Ace-G0ACE]

Interesting video and I'm glad the 1N34 did well as I have 106 of them! Actually they are 1N34/A, but I've collected my variable capacitors and other parts, so nearly ready to go! Thanks for your work in producing these videos.

[@Pootycat8359]

I was interested in this subject for another reason---biasing a diode in order to make an AC voltmeter (analog, of course!) with a scale that is linear, not compressed at the lower end. By the way, this video is one of the few on the subject produced by someone who actually understands electronics!

[@daveschmarder-1950]

I really liked Ben Tongue. He would call me once in a while and we would chat. Ben was kind enough to review a couple of my crystal set technical pages on my website. I'm glad that his website stayed up after his passing. I imagine his son did that. My radios turned out better because of his website. He also evaluated an impedance matching transformer that I had Hammond in Canada make for me. A real gentleman, one of the best rf engineers of the 20th century.

[@milesprower6641]

Some Florida insurance company has taken over his site! It's no longer there! We need the site back!

[@joebidet2050]

Date love your site You are awesome Thanks for sharing all your hard work !

[@bob4analog]

Thanks for varifying that biasing a detector diode works. I've had some folks tell me it wouldn't work. I'm going to build your circuit. Always enjoy your vids. 73, KD5MHQ

[@KarlsLabReport]

Very good stuff! Great to know one can use a 1n914 switching diode for a crystal set and make it work reasonably well.

[@andreasboll5984]

Another great video 👍 God bless you Thanks so much from Germany 🤗

[@LowSpecLinuxLaptop]

Cool. Homemade crystal sets are lots of fun

[@johngifford8335]

I'm from Webster New Hampshire love your channel.

[@MIKROWAVE1]

I live in Hooksett. You can't get to Webster from here.

[@denny71730]

Thanks so much for this series on Crystal Radio Technology. I guess now I have to build one! Thanks for the inspiration! 73, KF5FHO

[@francoisdastardly4405]

Very very very useful. Many thanks !!

[@area46241]

Excellent! Did not know this.

[@kensmith5694]

The best diode also depends on the headphone impedance. You want to match everything to to load. Lower load impedances go with bigger junctions in the diode.

[@daviscd3dca261]

Elvis crespo sounds on the crystal radio , cool!!!

[@Gordonseries385]

a effective if noise clipper for am and ssb . enjoyed you video

[@Andy2e0ree]

Great video many thanks

[@attilarivera]

Fantastic!

[@davidluther3955]

GOOD INFORMATION GIVEN.

[@lgau31]

One way to do this would be to set a small current using only a resistor and a higher voltage to define a current source. By applying a few uA, you will put the diode in forward conduction and no need to adjust voltage. As starting values 1.5v battery and 1M resistor. Using highZ, you can apply current directly on diode without decoupling.

[@billsheppard9368]

Back around '59 or '60, there was a build-it article in Popular Electronics (or possibly Electronics Illustrated) for a "HiFi AM tuner" using a biased diode. I don't remember the bias as being adjustable though. (The idea of it being Hi Fi was unrestricted signal bandwidth, unlike a superhet.)

[@user-uu6sw6fi6w]

Nice job! Like!

[@gregsimopoulos4708]

Very enjoyable and informative, all of your videos have great pedagogical organization and flow... Thank you for taking the time and sharing... 73, Greg (KC9ZEW)

[@chronobot2001]

Great video.

[@MIKROWAVE1]

Thanks for watching a bit of an odd crystal set vid!

[@fredriko.zachrisson9711]

Very interesting. This was very helpful. I am just getting into crystal radios, and i am very interested in grounding and ground/telluric currents. Have you made a video about that, or brought that up in another video?

[@Pootycat8359]

When I was a teenager, and getting into electronics, I had an older friend who was a tech, who described the following. He said that during WWII, when civilian radio communications weren't allowed, hams and other experimenters would communicate in the following way. They'd apply audio or LF RF to two ground rods, spaced some distance apart, to transmit, with a similar set-up at the receiving end, feeding an amplifier input.

[@tubeDude48]

Where do you get the steel ball from. Also, keep crystal video's coming.

[@wanderleyr.dasilva8290]

Obrigado pela sua informação acerta do rádio Galena (Cristal); eu já tenho feito um em 1995, mas assistindo seus vídeos, pretendo fazer um outro...

[@NebukedNezzer]

my Drake SW4 am only short wave receiver uses a 10 megohm bias resistor to apply a small amount of forward bias.

[@Chris_Grossman]

A backwards tunnel diode would be interesting. NOS Russian ones are available on fleabay, The TekWiki has a page about them.

[@krzysztofszmel7503]

O.ten jest najlepszy .W prezentacij radio i krotkofalarstwa.Pozdrawiam szanownegoo Pana.

[@MIKROWAVE1]

krzysztof, dziękuję za obejrzenie moich filmów radiowych.

[@kd5ozy]

been using 1n5711's and having good luck with them

[@benthere8051]

I realize this is a crystal radio thread but a question occurred to me. Would it be possible to phase-lock an oscillator to the carrier and do a synchronous detection of the audio with transmission gates? Even a lowly 4066 only has about a 70 nS delay and could be fast enough. These days, it's probably much easier to do it with DSP techniques. I had always wondered if you could bias a silicon diode to near conduction and use it as a detector for a crystal set. Enjoyed the video. Many thanks. BTW - what is the forward voltage of silicon carbide and galena?

[@KeepEvery1Guessing]

It would be interesting to test the effect of bias on traditional point contact arrangement detectors ("cat's whisker" on galena, razor blade detector).

[@MIKROWAVE1]

Actually many of the very early detectors such as the Silicon Carbide (Carborundum) types required bias.

[@dz-abouttechnique1849]

Nice video!!

[@MIKROWAVE1]

Thanks for the visit and I hope you build a biased crystal set.

[@dz-abouttechnique1849]

@@MIKROWAVE1 You are welcome! It's in the plan.

[@sliderulelover]

Outstanding presentation! Very informative and I liked that you compared many diodes and how they performed in detecting signals. What antenna does this radio use?

[@MIKROWAVE1]

A 100 ft inverted L Longwire.

[@davidszasz1335]

Fascinating, albeit "biased" video (forgive the pun). Could you point me in the direction of a crystal receiver circuit for the 40 meter and above CW bands. I know that a BFO or interrupter circuit as described by Jones in the 20's for CW would be required for listening due to AM envelope. Your videos are always interesting, thanks

[@greedyfirstalgorithmlast26]

Didn't Ben Tong have a Column in Popular Electronics magazine or SWL magazines?

[@russedmonds227]

Great video! one question at 13:13 you said the vintage 1n34 diode voltage drop of .315 v is lower than the 1n270 voltage drop of .241 v is that right?

[@jamesmoffat9754]

Idle curiosity here but could ambient light affect the bias of a glass diode?

[@mohinderkaur6671]

The best diode I found ever - was as a child - a zero biased capacitor coupled germanium transistor with a headphone in the collector to a battery. Most AM is spanish or chinese now. Hard to find interest programming on AM. Why not use a germanium transistor instead of aschottky ? It will provide gain and can be made regen also.

[@Kamakazi_-tp2lb]

I noticed that tuning capacitor your using looks home made ? (maybe) if so what material did you make the plates out of ?. I would not mind trying to make an air core tuning capacitor from scratch. any advice would be appreciated thank you.

[@mohinderkaur6671]

Remove those galvanized brackets to improve coil q. Improve matching of antenna to coil by more taps . Taps on secondary maybe useful too. Home made diodes using zinc crystals have been used. some even have a negative resistance.

[@MIKROWAVE1]

All great Crystal Radio tips that come from experience.

[@albertodelrio9206]

Pero entonces, esos soportes galvanizados ,mejoran o empeoran la situación ?

[@attilarivera]

👏👏👏👏👏

[@mrkattm]

What are you measuring with your RF volt meter ? Voltage across the diode or across what looks like a capacitor?

[@MIKROWAVE1]

That is an AC RMS Voltmeter that is measuring audio level only. It is flat out to a few MHz.

[@chronobot2001]

I really would have liked to see the performance of the voltage doubler crystal radio.

[@MIKROWAVE1]

I have built these as well as full wave bridge sets. They all work, but you don't get something for nothing. Usually the voltage drops and impedance differences tend to wash away the gain you think you should get.

[@pixelpatter01]

After you went through all those diode possibilities it occurred to me you hadn't mentioned LEDs. They might even give off a little light. Since LEDs can actually produce a voltage, perhaps an LED could be biased by the light from another diode ? Thanks for your interesting projects. I came here looking for Alfred P. Morgan references as I've always been a fan of his books.

[@MIKROWAVE1]

Wow! Maybe this is the breakthrough to free radio and light?

[@RayZ7834]

I made one of my crystal radios with a multi-switch to choose from various crystals or diodes including a quad or little circuit with 4 crystals mounted on it

[@MIKROWAVE1]

Fancy setup Ray. Any pictures for the resource page on Facebook?

[@RayZ7834]

@@MIKROWAVE1 what is the page name ?

[@RayZ7834]

@@MIKROWAVE1 I just noticed the "K" in your name here so I am linking to you on Facebook and I'm glad I am able to.

[@MIKROWAVE1]

Mikrowave1's Radio Resource Page

[@RayZ7834]

@@MIKROWAVE1 Privacy settings won't let me post my picture - not sure if the privacy setting is on my end or yours

[@DubiousEngineering]

What was the part number of the schottkey that gave the best results? Thanks

[@MIKROWAVE1]

BAT-85 and BAT-46 and 1N5711 all perform wonderfully.

[@DubiousEngineering]

@@MIKROWAVE1 thank you!!!

[@NebukedNezzer]

I use a HOT CARRIER diode in my crystal sets.

[@BruceNitroxpro]

Seems like a hard way to characterize a diode. Any thoughts on a curve tracer approach? de Bruce, KQ2E

[@MIKROWAVE1]

DC characterization is a great starting point. Curve tracing is a fantastic instrument method: a first principles grader. But the magic of RF diodes seems to defy using this method alone.

[@BruceNitroxpro]

@@MIKROWAVE1, What tool and approach can extend the diode as far as the average user can handle? I ask because the methods used in industry depend a lot on metrology and standardization, goal oriented design as well as physical design. This is a wide tapestry to expose the beginner into, and you are facing that group here.

[@bobbiggley6992]

Would it be possible to use one half of a germanium transistor such as a 2n109 as a detector?

[@MIKROWAVE1]

Sure! A Germanium Base to Emitter junction makes an excellent signal diode.

[@Broken_Yugo]

Not just possible but quite common in germanium era transistor radios as a cheap trick to up the advertiseable transistor count.

[@SkyLabZaamslagtheNetherlands]

Hello can you help me unmute a radio between the channel sweep? I cant find any diagram on this model, how to unmute this.... Its a small radio type cs-106. Can you help me please?

[@kensmith5694]

What signals do you have access to? The AGC voltage of some radios can be accessed.

[@SkyLabZaamslagtheNetherlands]

@@kensmith5694 fm? Am? Unmute the sound between channel sweep!?!

[@kensmith5694]

@@SkyLabZaamslagtheNetherlands You need to be much clearer with the descriptions. I can give you a few hints about dealing with muting. A common trick is to take the audio and look for lots of high frequency noise. That is the usual indication of no signal. Depending on the radio, a high pass at something above 10KHz will serve to isolate the high frequency noise.

[@SkyLabZaamslagtheNetherlands]

@@kensmith5694 i want the same like this radio! Sweeping through the channels and remove the mute between the Channels. Just like this radio.... Simple as that. kzbin.info/www/bejne/b4GvpYFrfLCop5o

[@panjisetyonugroho5219]

Can we do it to FM station ? I saw many FM crystal receiver, unfortunately it is hard to get germanium here,, I use 1n4148 could it be biased that way ?

[@MIKROWAVE1]

Yes the 1N4148 will work just as well when biased.

[@ve3cwq47]

Another superb, deep dive into the crystal radio art/science. Fascinating. i notice you have your trusty "The Boys' First Book of Radio and Electronics". I found a pdf copy at www.americanradiohistory.com/Archive-Bookshelf/Technology/The-Boy's-First-Book-of-Radio-Morgan-1954.pdf for anybody who's interested. It brings to mind a book that captivated me as a young lad back in the early 70s. I must have retrieved it from my local public library a hundred times. I would love to find a copy somewhere; if only I could recall the title. Although not specifically about radios, there was a chapter that described the construction, and provided a schematic, for a radiotelephone transceiver that could be used while playing capture the flag. I'm not sure, but it might have been published in the 1940s or possibly the 1950s. If you or one of your viewers recall such a book I would be extremely grateful if you could provide me with the title.

[@marcosyreme]

Uma tradução ajudaria muito.

[@chronobot2001]

I'm surprised you didn't use a modulated signal generator so that your comparisons would be referenced to a known signal strength.

[@MIKROWAVE1]

My generator does do a good job on AM, but it has been years since it was anywhere near calibrated. I need to get a new one for sure.

[@GrantsPassTVRepair]

The 1SS86 Hitachi diode has been in interesting diode to experiment with. It didn't seem to work real well in my broadcast band crystal radio, but it sure works well at higher frequencies. Here's an experiment I did using them. kzbin.info/www/bejne/rHm5nn1roalsoMU

[@MIKROWAVE1]

Wow impressive work. These crystal sets keep folks interested.

[@Ricardo90]

Uma pilha de água e sal?

[@MIKROWAVE1]

¡O una batería de pomelo!