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- เผยแพร่เมื่อ 7 ก.ค. 2024
- Answers to, and fixes for, the most common reasons that crystal radios don't work. The only one left out (which is very uncommon, in the US anyway), is no AM station nearby.
NOTE: Use a carbon, not wire wound, resistor.
WARNINGS: Never run an antenna near a power line of any kind. Never use a radio with an antenna during a lightning storm. Always disconnect and antenna when it is not used. This is not a complete list of antenna safety items. If you don't know, learn first or don't do it.
VIDEO: Best/Easiest DIY Crystal Radio - No Batteries, No External Power (4K)
• Best/Easiest DIY Cryst...
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0:00 Introduction
0:54 Absolute Fails
3:54 Likely Fails
7:12 Coil Problems
9:32 Small Issues That Add Up - วิทยาศาสตร์และเทคโนโลยี
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RELATED CRYSTAL RADIO VIDEOS:
Best/Easiest DIY Crystal Radio - No Batteries, No External Power (4K)
th-cam.com/video/fLVCqZGpv3U/w-d-xo.html
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It's been a long time since I've had a crystal radio to tinker with, I may need to build one again.
Thanks for shedding some light on this
I have a couple good designs. This is the one from the boy scout manual (slightly improved):
th-cam.com/video/mt-s7pf-U5Q/w-d-xo.html
Excellent advice and good listening! Some of mine have been pretty ugly, but fortunately no crystal set ever failed simply for being homely. P.S. Remember your ABC's - Radios fail because of Antennas, Batteries and Connections. And crystal sets have no battery so you are ahead already!
Excellent suggestion. This is a huge help. Now to rebuild the radio so I can place it in the machine I built that allows me to travel through time....I call it my...." " " time....machine " " "
3:48 You can also use Litz Wire as a substitute for enamelled copper wire and it should work, Litz Wire is what they use to make the coils for Ferrite Rods that were used a lot in portable transistor radios from the 50's and 60's.
Your videos are easy to follow and are very informative. Thanks.
Glad you like them!
If you ever run out of ideas for more crystal radio videos (I doubt that’s possible), can you do a video showing us soldering shorter lengths of copper wire to make the coil-and how to minimize the problems involved with disrupting a perfect coil?
I just did that, but did not make a video. I drill a hole in the tube. I push both ends of the bared wire into the hole. Then I twist the 2 ends of the wire together inside the tube (it's a bit tricky) and solder it.
I really like your videos and I'm very thankful for all the information you provide.
Thank you. I'm glad you find them useful.
Good info on coil length also. When I made a tuned loop antenna, it was too long and shortened the reception bandwidth! I had to use a needle attached to one of the tune loop lead ends to short out the antenna until I reached (roughly) 16 kilocycles-John in Texas
Good stuff, thanks!
My father, who was a fantastic Chemical Engineer/former Machinist, helped me build a very nice nonworking xtal set back in the 1960's. Looking back, I now realize that not scraping the enamel off of the coil wire can affect performance!;) Those piezo earphones are notorious for not working, even if they are the correct ones. Of course, ANY open in the circuit will affect performance and one MUST have a good EARTH GROUND or the radio will not work. My dollars worth-John in Texas
Do you still have the one you built? Or maybe you can rebuild it and make a video. If you do, leave a link here; I'd like to see it.
I once tried an LED, and it gave me the best signal of all the diodes I tried. It was one certain LED, I'll do some experimenting, maybe try a blown LED.
Great information _ thank you.
2:28 Those crystal earphones are high impedance devices, because they are high impedance devices they don't load-down the circuit they're connected to, that's why they work, a crystal-set radio circuit is a high-impedance RF circuit that is, it operates at very low currents maybe a few micro-amps or so, most modern iPhone earphones and etc are low-impedance devices and need to be driven by a low-impedance circuit in order to operate correctly.
Can an old rotary telephone earpiece(that has a metal diaphragm coil ans a magnet)be used as a ear phone for audio sound of this crystal radio?..
Can an old rotary telephone earpiece(that has a metal diaphragm coil ans a magnet)be used as a ear phone for audio sound of this crystal radio?
Thank you so much for the tips!🙏 Could you make a version of this crystal radio with a speaker and a battery? It would be amazing to have this device playing without the earphones...
I have a video like that. I show how to connect this to a speaker and amplifier.
Either use all brass or all stainless or solder your connections. Mixing two dissimilar metals causes a galvanic action that will corrode your connections. Never use a combination of aluminum screws and brass/copper washers as they react the strongest with each other. This goes for any radio you may construct.
I have a question: can you use a 4 pin tube base to wind coils on so you can change bandwidths? Thank you.
Yes, older radios used to use changeable coils or tapped coils to reach different parts of the band they wanted to receive. But back then all bands were AM, so one could do that. Today many bands are FM or other and this radio won't work for those.
I have an interesting problem. I'm using a 1N914 diode, a 120' long steel electric fence wire for antenna, and a regular earpiece. Every thing works except I only get the Spanish church channel on 1140 AM. I have tried nearly every configuration of tuning possible and it just stays at that band. Thank you and nice videos on these nifty old radio receivers.
The antenna and low sensitivity diode will "work" but will only the the strongest signal(s).
Thank you for the good input. The antenna on its own is capable of lighting LEDs six in series. Guess I need to find a better diode.
I have trouble getting 1N34's here down under. I have to try get them from eBay.
I long time ago I made a crystal radio very similar to yours without any resistor and the signal came in crystal clear (no pun intended). Even when hooked up to a 30 watt amplifier. Now I can't get nothing but a little static sound. At the time we had a local AM station, but I could also get a few other stations (al be it not as clear). I can still get a few not so clear stations on a cheap junk clock radio which was never very clear. I expected some oxidation after 20 years of sitting and I cleaned up the connections and checked for continuity, but I can get it to work.
Maybe the signal is too weak, but I should be at able to hear something. I'm using the same diode as you are. Is antenna length super critical, because who knows if I cut off a piece of the antenna over the years for another project. My antenna is about 15 feet long.
I used a 3/4 " plastic tube with very fine enameled wire with excellent results.
I have a video on when things go wrong: th-cam.com/video/kCxQ8iPQx4s/w-d-xo.html
You say you don't have the resistor, which is OK if you are using a 1950's type crystal earphone, BUT, if you are using the newer piezoelectric earphones then without the resistor you will just hear static and popping. AND, with the newer style earphone, you absolutely don't want to add the old capacitor they used to use.
@@tsbrownie Thank you very much for that info. I must have a crystal earphone. I think the diode I have is old school too, because it looks more like a resistor with black, brown and red bands, instead of the modern glass type.
@@gordthor5351 Give it a try and let me know.
On one of my crystal radios I built I added a rotary switch that selects from 4 different diodes to demonstrate the differences in how loud each different diode is. I intend on adding 2 more - a D311 and a D311A. My loudest crystal radio uses a Russian D311 diode. Also installing a simple coil between the antenna and my crystal radio also increases volume. Unfortunately I can only pick up either one station at 1590 or that one and another one simultaneously
That's an interesting experiment. You should post a video on it. Leave the link here. I'd like to watch it!
@@tsbrownie I might try that. I posted some music I played under my name Ray Zaballa ( not so great ) I will try to do as you suggested.
I can no longer post videos from my phone to TH-cam . I used to be able to do that and then some changes happened and it's now no longer available. I will try to link up to them
Ive tried numerous and found the d311 the best too
vf is just .150
very low
Thank you. I've made crystal sets in the past and they worked OK just not loud like yours even with my radio station running a kW and just 4 air mikes away. At oue point way back then I bought one already put together. It was OK, just not really loud.
Recently it took me 2 weeks to get a crystal oscillator to work on 7 mHz. I'm learning to never take anything for granted. Lately just about everything that can go wrong does go wrong. lol I now have transistor testers, LCR testers set. Maybe I need some tester testers. Thanks for the tips.
Good on ya! Oscillators can be tricky, and higher frequency makes it exponentially so. I made my first one by accident by feeding the output of an op amp, through an old TV coil, back into the input. After that I was hooked on resonance.
Coils are important. I know I keep advertising myself, but here's a video on some coil sizes/wire sizes where I've already run the calculations and in the case of 19 AWG, already made several radios. th-cam.com/video/ejHk5tFeKHk/w-d-xo.html
It's worth the hour+ and cramped hands it can take to beautifully hand wind one.
Oh, BTW, I have another video on adding an amplifier to a crystal radio, if you do want them louder. Personally I'm a purist and don't mix power with my crystal radios! ;)
@@tsbrownie lol I'm already watching some of your other videos. 😁 So your self promotion is a good thing and helpful.
When I get my diode going I'll make the one with the L match.
30 years ago I was heavily into making home brew projects. I read after Doug DeMaw and Wes Hayward and made a DC (direct conversion) receiver for listening to morse code. I made a contact in Canada and a few more with the VFO only. It measured 140mW on an oscilloscope.
I didn't realize how much anyone can forget when they get out of practice.
I'll keep on piddling and I'll get there with perserverence and your tips.
I watched your video on bad crystal radio designs and it hit me like a slecge hammer. Almost every one I made used the variable capacitor. I'll wind the coils like you suggest and can leave out that cap.
Good on resonance and crampped hands. I'm thinking about making a jig so I can use a variable speed drill to turn the PVC pipe for wingind coils. I suspect the jig can't be harder to make than the piece you made to mount the variable capacitors on the 1979 radio.
@@southernexposure123 Wow, I'm impressed with your DXing! I hear you on forgetting. I had to relearn a bunch of stuff before I made my first video. (I actually reviewed the original boy scout handbook I made my first one from!)
I'm putting together a winding jig and a video (of course). It's just 2 wood cones (I've seen them online for about $1) with a threaded rod through it. You can mount it in a cardboard box of the right size. Cranks are good, but you can just turn the core by hand. I won't use a drill, because it's easy to kink/bend the wire, and tightly spaced turns are not just beautiful, they make for a better radio.
I'm also going to start experimenting with "natural" diode replacements like galena, etc. The 1n34a is starting to get hard to find, then there's the fake factor.
Let me know if there's anything I can help with.
@@tsbrownie I didn't know winding jigs were already offered so cheap. The reason I thought of a variable speed drill was so I could run it slowly at a set speed and control OFF / ON with a toe or a knee. A few years ago I used a battery fpowdered drill and set the speed just about like rock polisher to make black powder. I made it only once. It's too scary and easy to get an explosion. I set my ball mill outside a few hundred feet from my house. Then I hesitantly approached it for stopping the mill.
I likely wouldn't have thought about wood for cores, although I have seen some coild wound on forms that weren't round.
I don't think I have the patience to try setting up a galena. Oh earlier tonight I saw a video show and tell how to detect whether the 1N34A is real or fake. Under that video was a comment telling how Skotchky diodes have some sort of benefit over the 1N34A. I think it was something to do with better selectivity.
I was going to reference that specific vileo with a link, but a seatch yielded that there's more than one video on that subject:
th-cam.com/users/results?search_query=how+to+tell+if+a+1N34A+is+real+or+fake
The one I watched was made by a fellow with a heavy accent, maybe indian.
I appeaciate all the chat and tips. My next undertaking will see how big the wire is inside a microwave transformer. I suspect it might be too small for our purpose.
Have a good night and I definitely will get in touch with any more mysteries or discoveries. Thank you.
I've reserched microwave ovens for wire. I knew people were saying you could get killed by the high voltage. I thought I knew how to avoid that.
But my research online tells me there's more stuff inside those ovens that can cause severe health issues if it's breathed into your lungs. I think I'll just buy my wire for coils...
Can i use an 1n34a do-35? I mean this one is a Germanium Diode, written "1N34A DO-35".
And if i made my own crystal earpiece (i sanded the metal plate until it lost 50% of thickness) with regular 35mm piezo element, would it works?
Can you please tell me average voltage of the audio output of this crystal radio?
The do-35 is the package type, and that does not matter. BUT I did a quick search and many, many schottkey diodes are being sold under that label. They do not work well. I have a video on how to test for fakes. I have never tried that to make an earphone. Please let us know how well it works. The voltage depends on your antenna and ground, how powerful the radio station is, and how well the radio is made.
Does the diameter of the plastic tube you coil the copper wire around matter as the tube I have is about half of yours?
Yes, it matters a lot. Changing any of the dimensions changes the frequency range of the radio. If you get outside the AM band, the radio will work badly or not at all.
I’m curious, you mentioned how using bare copper would essentially be like using a copper tube. Once you sand a strip for the wiper, how is that not also a solid connection?
There is still insulation between the each wire. Only the top of the wire is bare.
Nice
Why did you use a resistor connected to the coil , & what is its value?
Thanks
The specifications of all the parts are in the description. The resistor is to dissipate charge on the piezoelectric earpiece.
@Kirk Rundstrom Science is all about observation. Sounds like you were a natural born scientist!
On the right side of the radio, was the wire, earphone, and resistor between the 2 brass washers or under the 2 (between the 2 washers and the wooden base?
In between 2 washers is best. If you have only 1 washer, put the wire between the wood and washer.
@@tsbrownie Thank you for the help
Can you use copper, multi-strand wire -or- is solid necessary for your antenna?
Most that I've seen / used are just single strand wire. It's almost always bare wire, so multi-strand would hold water longer and corrode faster. In theory, multi-strand may also deliver a less sharp signal if the different strands receive / send signals at even slightly different speeds / distances.
@@tsbrownie Okay, thanks for responding. :-)
What is the optimum diameter fo the coil tube?
The details are in the description under each different radio video. Rules: 1) The system has to resonant in the range of the AM radio band. 2) Generally speaking a larger tube has a higher Q (more efficient) to a point. (See rule 1). 3) I have a video on the factors involved in the coil. This is important. Guessing won't work.
My brother
How many the coil turn
Thanks
I put all the information in the description for you.
My crystal radio only works when I have my hand on my variable capacitor or on the coil. When I remove my hands it stops. I know I’m picking up a station because I can hear music. But when removing my fingers it just stops. any solutions to this ? And also a few bits of info, I’m using a plug in usb speaker then attaching my heads to the speaker jack.
The signal on mine often increases when I put my hand near the coil. That is normal. It sounds like the station you are getting is very faint. I can only guess, but I think your USB speaker requires too much power and is interfering with the radio circuit. It is BEST to use a crystal earphone. Next choice is to use a battery powered amp connected via a small cap in serial. 3rd option, try putting a small capacitor in between your USB speaker (in serial) to cut down on the power draw. That **might** help. Let me know if that helps.
@@tsbrownie alright thank you, I’ll let you know how it goes later. I ordered a crystal earpiece a few days ago and it should actually be arriving today or tomorrow. I also might try to move the radio around, my house is very electrically loud and might be causing interference.
@@tsbrownie still no luck, I ended up adding a 0.1 UF capacitor and a 43k resistor onto the radio. The good news is that I hear a light buzzing coming through the speakers “Which is very faint”. And I don’t even have to have my hands on any of the metal now. The bad news is I can’t hear any radio channels. I think my last options are to wait for my High Impedance ear phones to arrive. And also increase the intenta now that I have added those components on.
@@Adam-qd8jh if you can take a video and post it, put the link here and I can take a look. You might also watch my video on antennas. How far is the nearest AM station from you?
@@tsbrownie I have a few radio towers that broadcast AM around me. One is 6.4 miles away from me, and the other one is about 7 miles away. There are more but they are in the range of about 14/24+ miles away.I was actually going to make a 75+ foot antenna as the one I have now is a measly 10 to 15 foot antenna. I will upload and send the video link within a few hours.
a good ground is of most importance--it is the return or completion of the antenna circuit--i once had a poor ground and it worked sort of--when i replaced my poor ground with a good 8' ground rod the difference was day and night--
sorry--the strike through seems to always happen on utube--not sure why--
I did a search on youtube and strike through and they said it's the use of hyphens that does it. Let's try. hyphen -this is a test- hyphen. And it works. The hyphen has to have no space between the character and itself.
@@tsbrownie --thank you sir.. i will try to avoid the hyphen from here on..my old english teacher would be upset with me if she knew i was doing that anyway..
it worked.. thanks again..
What's the guage of the coil's wire guage?
All of my videos on different radios have the specifications in the descriptions.
@@tsbrownie yes I see now lately.
Would a old telephone handset work
Good question. The really old ones were crystal type, and they will work. It's worth a try, and it it does not work you go with the crystal one.
I’m in Europe here is fm stations, that will not work here ?
No, it will not work with FM. AM only.
@@tsbrownie thank you for the fast reply :)
Why would paint affect the coil's performance?
Any paint that contains pigments is a problem. Pigments are chemicals that contain metals. Metals react with the electromagnetic field of the coil. Colored paints would be similar to covering the coil/tube with aluminum foil. Clear acrylic spray paint is not a problem.
@@tsbrownie THANKS SO MUCH, could be a problem on one of my recent builds. It's a pretty build, just isn't working. :)
@Joel Ohmer If you post a video of it leave a link. I'd like to see it. Also, I have a video on common reasons they don't work.
And how to connect a metal gang for tuning?
I don't understand the question. Do you mean a variable capacitor? This type does not use a capacitor.
Yes. I mean dielectric metal gang condenser.
Hard to proove the diode is correct. Thats my big problem hard to find this diode and trusty saler.
do you need an electricity for this?
No, the power comes from the signal itself.
@@tsbrownie :O awesome! But is it possible to tune into 108 MHz FM with this?
@@MiiMaker FM works very differently and requires much more complex decoding.
I make it work but it have to use mini ampli..if not no sound.
Something is wrong. If the station is within 15 kms, you should hear it clearly with just the earphone. Here is a video on common problems:
th-cam.com/video/kCxQ8iPQx4s/w-d-xo.html
Hello my friend? what size capacitor, is the one in this video?
Only 1 of my crystal radios uses a capacitor (and it uses 2). th-cam.com/video/VJ80Nm9KSkE/w-d-xo.html
Crystal radios from when I was a kid 60 years ago had a small capacitor, BUT they used a different type of crystal earphone. The new crystal earphones are piezoelectric (with built in capacitance), and if you add a capacitor instead of a resistor you will get static.
@@tsbrownie Thank you so much for your reply back, lol lol I'm going to let my grand kids make one Like i made 60 years ago lol lol
@@richardsmith7783 Very cool! It's a bit of magic shared between generations. Have fun!
Yep, i built this one myself and i ant get that thing to work, I made a tesla coil for wireless got that to work but this radio, not so much !
If you have an AM station within 30 miles, it should work. Give it a check again and compare it against this video to see why it's not working.
@@tsbrownie will do, I'm going to try one more time and i will also try with a varible tuning block i had from old radio, but not sure what side is am !, but thanks
When ours don't work, Pa just spits in the back of it and whomps it.
Andy Griffith?
@@tsbrownie Yep, glad you caught that
You did not ever give the value of the resistor!!!
A 10k is usually good. The specs are in description of the actual radio builds.
@@tsbrownie Wasn't sure where to find it. I plan to use a ferrite rod antenna, with VTC ( 365 pF ) as I need to be mobile. Thank you very much!!!
@@davidj.lebaron709 That's interesting. Please post a video when you are done. I'd like to see it.
@@tsbrownie Thank you, will do!!!