My New Favorite! Crystal Radio with Antenna Tuner
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- Опубликовано: 28 сен 2019
- The wiper style crystal radio is easy and cheap to make. It has a few drawbacks including: cross-talk, tuner roughness and selectivity. This new design uses all the same easy construction techniques and low cost of materials. It really works well. It's now my new favorite!
Depending on your design (coil mostly) it can receive in the AM broadcast band, approximately 535 to 1700 kHz. In actual use I have received from 1295 to 540kHz. On the 1295 kHz I had to short out part of the left side coil using only about 2/3rd of the turns. So fewer windings on the left side would be better.
See Warnings below.
OPERATION TIPS & TRICKS
- A good antenna is important. Longer is usually better (see antenna warning below), a good ground is next most important. More below
- With some stations, you can put a finger or 2 or 3 inside the tuner coil to improve reception. Move them around for best reception.
- A finger near the coil can also improve reception. Touching the coil directly usually lowers sound volume, BUT a piece of paper or thin plastic between finger and coil often improves sound / tuning. Move finger around.
- Touching different parts of the radio or getting near them can affect performance.
MATERIALS
- 3" PVC pipe (3.5" OD), 18 cms long. NOT painted.
- Left side coil: 55 turns, 0.55mm enameled wire
- Right side coil: 110 turns, 0.55mm enameled wire
- Note: 5 turns blank space between left and right coils
- 2 bike spokes/stainless rod, about 2mm, about 18 cms
- 2 wood/plastic knobs for wipers
- 2 Fahnestock clips and screws
- 6 brass washers
- 3 stainless screws (for wire connections)
- 1 crystal earphone
- 1 diode, 1n34a (MUST be this)
- 1 resistor 30k-40k ohms (experiment for best sound), carbon, not wire wound
- 4-6 washers (depending on design)
- 2 screws (to secure wipers)
- 2 felt disks (or springs)
- 2 wood "towers", 1x2 inch (1cm shorter than the MOUNTED coil)
- 4 screws (under towers)
- 1 Wood base 20cms wide x 17 cms deep
- 2 pillow blocks to hold coil
- 4 screws to hold pillow blocks to base
- 2 screws to hold coil to pillow blocks
(See other videos on construction details of wipers, knobs)
WARNING: Radio antennas represent a fire, shock, electrocution, etc. hazard.
- Always disconnect antennas and ground outside when not in use.
- Never connect radio to any source of power. Not house current, nor batteries, nothing!
- Never use the radio during lightning storms or if lightning is expected.
- Never run an antenna over or near power lines.
- Disconnect antenna when not in use.
- Never ground to electrical items, plugs or similar.
- If you don't know, don't do it.
VIDEO: Best/Easiest DIY Crystal Radio - No Batteries, No External Power (4K)
• Best/Easiest DIY Cryst... 
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Top 10 channels on RUclips. Not only for radio builders, but for interested youth (or anyone) who wants to learn about radio in terms they can understand, and with an abundance of previous videos to refer to when you’re lost.
Hey buddy, I have watched 10 or 12 video on how to build Crystal Radio NONE of them explain as good as you do!! You need to repost this video for all kids to see!! Thank you so much sir!!!
Well thank you very much. I plan to remake it in 4K video.
Wow ! I'm growing more and more satisfied with your two coil design. After I modified mine to your design (even without making the turns to ground adjustment) I'm getting much better frequency separation.
Before the mod I could understand 3 stations with very much cross talk from even more stations and when I pushed in my paper core capacitor all the way in I could still hear the strongest station, but couldn't understand anything because the cross talk was still stronger. I haven't yet put separation to a hard test on the upper frequencies.
Now (even in the daytime) when I push the capacitor in (oh and I finally got my store bought capacitors) and when I add in the store bought capacitor in parallel with the paper core capacitor I can hear a few weak stations and understand them because there's now no cross talk way down in frequency. It's still not as sensitive as my TS 440, but that radio is a little more sophisticated. lol
Now on the crystal radio I easily find 5 or 6 stations now and separate those other much strong stations - "entirely" out with zero cross talk. I'm getting stations somewhere around 0.630 kHz. Weak, but steady. I suspect that station is 1 kW power and around 25 air miles from me.
You likely saw the uH numbers on my coils. I'm sure the radio tunes below the broadcast band, however I don't think it goes as far down as hams have frequency privileges.
Oh, I found out a few days ago that there's people who make their crystal radios modified so they can compete in crystal radio contests. If I remember correctly their rules say they can't be audio amplified. If that's so they're likely your brand of purists.
Great video, thank you for sharing!
Hello! that's a wonderful receiver! thank you for sharing.
it would nice to get one these..already built! Excellent job.
Thank you so much, I am going to try this and get back to you
Nice beautiful model
Very very thanks sir 🤗🤗
It gives me good ideas!
👏👏👏👏👏👏👏👏
This is a nice video!
I'm glad you like it
THATS AWESOME
Please disregard the question I asked earlier today. After thinking about it for a while I used the resonant frequency calculators and answered my own question by using a calculator for coils in parallel along with the capacitance needed to cover the broadcast band.
Actually, at the moment I have the radio working good enough to serve the purpose I hoped it would.
Thankyou
Thanks!
Thank you!
I made a little progress. Oh, and I got the new diodes. I have to amplify.
(I hunted and deleted that comment I asked you to disregard a week ago.)
I finally added the L-Match coil between antenna and ground from your *"My New Favorite Radio" *video. I waited to install that coil because I wanted to experiment with different main tuning coils first.
On my DIY receiver most of the stations are crammed at the higher frequency end of the band and I was trying to find a few semi-local stations down around 0.520 and 0.710 The strong higher frequency stations (1.130 and 1.460) wipe out the weak lower frequency stations. Those lower frequency stations are weak even on my commercial receiver with a 62 ft dipole up about 30 ft..
I made the L-Match coil on a sliding form over the top of the coil form of the main tuning coil. I made it slide - on - top- of - the - main - tuning - coil - form- so I could play with the spacing of the two coils to see if different spacings gives improved selectivity.
At first I played with sliding one coil inside the other coil. It did tune via the capacitance between the two coils, but I'm not tuning stations that way now. Eventually, I'll make a direct contact adjuster to short out coil turns on both those coils.
I'm very pleased at the improvement in selectivity. I can separate strong signals signals at the higher frequency end of the band now and I can even separate a stronger station from a weaker station nearby by just moving the paper towel core capacitor. Your arrangement negates the need for the capacitor. I want to see if the capacitor added helps selectivity.
My coil / capacitor combination now tunes the AM band plus it tunes outside the AM band on both ends. (at least the calculators say it does)
At mid day the strong stations at the top end still override the weak stations on the lower end of the band. Just to see I added a fixed disc capacitor in parallel with the variable capacitor and I still can't get the weak lower end stations at mid day. Maybe at night.
I saw a video that shows / tells how to get better selectivity from a DIY crystal receiver by adding tuned circuits. BUT I'm sure that's more than a purist wants to do.
As is, my DIY receiver will serve my intended purpose, I think.
Again, thank you for your patience and guidance.
Sounds very cool. If you make a video (which I'd like to see) don't forget to limit any commercial content to a couple seconds or youtube will take it down.
@@tsbrownie Thank you.
Right ! I noticed you kept the parts you recorded from your receiver to a really short duration. Isn't every word said on radio stations copyrighted? Can you claim creative commons or say this is for educational reasons or one or another of their accepted offerings that will avoid a take down?
Several years ago I had a copyright strike on a video. Given the chance to defend, comment or whatever it was told I could do - I told them I didn't understand the reason for the strike because there was no music on my video and the only thing recorded was me speaking. I asked them to tell me where in the video was the copyrighted material located, the name of the artist, the recording company, the publishing company the copyright owner etc. I got absolutely zero response from anyone. Even then it took several months until the strike was removed. I didn't lose any sleep over the issue. It's still a little amusing.
Actually my motive for making a crystal receiver is to use it as an indicator that a DIY VFO is working. A VFO is a major device for getting a ham radio, or other types of radios, working. There's a lot of people who are interested in electronics, ham radio etc. Some don't have, for all the various reasons, access to test equipment that could help them know they have a VFO working OR that their circuit isn't working.
Without some sort of detector / indicator then making a VFO is like trying to walk a tight rope while blindfolded and with your hands tied behind your back. An oscilloscope is too expensive for a kid to get. Dedicated small signal RF probe power meters are expensive and not found at the hardware store.
I once had a small analog panel meter (it was a CB radio front panel meter for signal strength and relative output power. When I got into making ham radio projects I wired onto that meter a capacitor and diode and maybe a resistor. I used that to see the relative output of my VFO, buffers, amplifiers etc. For some reason I can't get the same circuit to work now. Maybe the meter I have isn't sensitive enough. I guess I could make a few amplifier stages to drive the meter. I've found circuits that will turn LEDs or a meter movement to pick up small RF signals, but that was before I got enough transistors to try making those circuits. I guess I got too focused on the shortwave radio VFO indicator. Plus the project, IF I can make it work will be interesting as well as entertaining for someone wanting to get into making a VFO and a homemade shortwave receiver..
Another thought is to take apart old discarded electronics and scavenge transistors etc to make the crystal radio and the VFO.
Even after getting my first ham radio it took me a long time to get a VFO circuit to actually work. Back then I didn't know the VFO frequency until after I had a receiver on the ham radio frequencies. That, too is a couple of items not readily available to most kids and even some adults.
Anyway, I was playing around with my VFO one day while listening to my home AM radio and I heard something on the radio that was a little strange. What it was was my VFO signal. It wasn't actually the frequency of the VFO, but it somehow mixed the AM receiver frequency and the VFO frequency. Curious I tuned my AM radio to a quiet place and tuned through the VFO frequencies and I started hearing radio stations I knew weren't in the AM broadcast band. I had accidentally made a pseudo shortwave receiver. And the stations I heard changed when I changed the VFO frequencies.
By now you've guessed that the crystal receiver is my attempt to make an indicator that a VFO is working. It could be an interesting project that gives kids and young adults a way to feed their electronics interests without spending hard to part with resources needed for more important things than for hobby interests.
That's my story and I'm sticking to it. lol
Oh, a video? That was my main motive for this entire excursion.
@@southernexposure123 About the YT takedowns; I'm not a lawyer, so I can't say what's legal, but if I keep it under 2 seconds they leave me alone (some people say 3 seconds). Maybe their software just can't detect it. I had your same experience when a German company started making claims against all my videos and wanted compensation. 99% are just me talking, no background music. I complained loudly to YT that this company was just legally scamming people hoping they'd pay rather than fight. YT actually listened. It took a while and several attempts, but it broke through their wall of silence. (The German company was banned from YT for making false IP claims I hear.)
Your VFO tester is an interesting project. Could you not get results from low cost things like that $20 o-scope or I've seen $15 frequency counters? Sure making your own is more fun, but....
@@tsbrownie I made and edited out most of the video I made. I made explanations you already read in comments and I have too much received audio recorded.
I'll make a do over for when I decide to post to the public. Once I complete the upload I''ll make it an "Unlisted" video so it won't be available to everyone and I'll send you the link on this comment page which you'll click to watch.
Before I can make a public video I'll have to modify my shooting to limit the receiver audio long enough to show the result. It'll take some doing because the detector activates with a heterodyne right on the receive frequency audio.
I can link it to you because you'll be the only person with the link.
It should be uploaded before dark.
We have so many exchanges on enough of your videos I'm having to stretch my memory to get back to the page that's relevant to my comment. lol I guess that's a good thing.
I deleted the linked video, re shot it and posted a public version on my channel. It might have an advertisement added to it soon and won't be public any more on YT.
I want to build one of these with my grandson.
Great idea. Something both of you will remember. Let me know if you have questions.
I like the antenna tuner idea.
I wonder if you could use less coils on the other side and insert a ferrite rod in and out for tuning.
The ferrite rod could be attached to a bolt for fine tuning control.
Shhhhhh. Keep this a secret, but I am (very slowly) working on something similar.
@@tsbrownie how is the progress rn?
Sorry, just saw your comment. It's still in the queue!
Thanks
Welcome
Nice. As for the antenna, you can buy or make a "lightning arrestor". This will make your system safe from potential lightning strikes.
Q: What program are you using that turns your computer into an oscilloscope? And do you use a capacitor inline from the radio to the computer?
Thanks!
A1: I bought a rather cheap USB oscilloscope. It's both hardware and software. They don't make it any more. I hear that Hantek makes some good ones and I'd check those out next time I buy one. However my first choice is a dedicated unit because the laptop always has compatibility issues and it takes up lots of bench top space.
A2: No cap. The probes / scope are high impedance, and don't seem to affect the output.
I really like the antenna tuner concept, it address the impedance matching issue i think. How many stations did you receive across the AM band? How long was the antenna? What was used for ground? I don't understand why there is no need for a capacitor in the resonant circuit. Did the earphone act as a capacitor? Thanks for the neat project.
Thank you. Max stations I can recognize has been 17. The antennas run under the roof line. One is 7 meters and the other about 15 meters. Ground is a rod in the ground. Yes, modern "crystal" earphones are piezoelectric and have capacitance of their own. In fact they need the resistor to drain the excess capacitance or you will get very reduced sounds and lots of static.
I like it and can't wait to try my own version! I assume you used pvc plumbing pipe? We don't have the blue here in Michigan, are you using 2-1/2" which is 2.875" O.D. or 3" which is 3.5" O.D.? Just curious as there is almost a 2" difference in length per turn resulting in 27 feet more wire in the larger coil. Have you considered separating and mounting the coils on another piece of pvc to make the spacing adjustable? I built the K.E. Edwards design but wound the 'primary' on 2" which slides over the 1-1/2" (1.9" O.D.)secondary. I added 1/2" in length to the primary pvc and drilled & tapped in 1/4" threads and use a nylon 1/4" screw to hold the primary at any distance I choose from the secondary. Finger tight holds it in place just fine. This allows me to choose either sensitivity or selectivity at will.
Good questions. Yes, the 3" is actually closer to 3.5 inches OD. In testing I had 2 separate coils but found it made little difference. Bigger separation made for lower signal, which might help to quiet a dominate channel. The pipes must be the same diameter, you can't have one slide inside the other, that's a different design with different specs. I have not looked into the KE Edwards radio, will have to check it out.
Just gathering parts to make my first crystal radio. I've got a piece of 1.5" pvc pipe, 19AWG wire and you had mentioned in another video about 235 turns.. can I add the 30/50 turns for the antenna next to that?? I've enjoyed learning from your videos.. great stuff👍
Not really. The pipe size changes the inductance which changes the frequency range of the radio. Check this out: ruclips.net/video/ejHk5tFeKHk/видео.html
I got distracted and too busy to play very much with the crystal receiver. But, recently I accidentally added a fixed value disc capacitor (103) in parallel with the diode. It increased the volume on weak stations, but on a few strong stations it adds heavy distortion until the main tuning capacitor tunes off the station with the distortion. All the strong stations don't suffer the same distortion.
I didn't yet try smaller value disc capacitors. I'm still time limited, but will get back to that experiment.
Right now I'm trying to make a variometer. We shall see how that goes.
@@tsbrownie I don't recall if I mentioned it before. It's easy to change the broadcast band receiver into a short wave band receiver.
I removed both of the modified boy scout radio coils from the circuit. It's quicker and easier to just use a different diode for the radio.
I have a coil of 11 uH and one of 14 uH. I put each of those separately where the main broadcast band tune coil was. Then I connected the long wire antenna to the diode. There's at least two high power stations around 4 mHz and 6 mHz which are loud. They'll only be heard after dark unless you're physically close to the stations.
Each of those coils will hear each of those stations separately by using a variable capacitor of value up to 190 pF. A paper towel core capacitor will do.
@@southernexposure123 I'll have to try that.
@@tsbrownie My antenna is maybe 75 ft. long and at it's highest about 20 ft. I assume more frequencies can be heard with other coils and different antenna lengths. I should use my store bought receiver to search frequencies at night and make coils to resonate there.
@@tsbrownie I watched your most recently posted build radio with all the upgrades and modifications. Nice.
I also played with different coils for shortwave frequencies and with the disc capacitor paralleled with the diode.
When the band is weak the capacitor (103) increases the volume without changing the tuning frequency. But on strong signals it often distorts the audio and makes the volume too loud. But remember I'm using a LM386-4 chip amplifier.
Using a 7uH or a 14uH coil tunes almost the same shortwave frequencies somewhere between 4mHz and 6mHz. But the volume is lower with the 7uH coil. I can delete the L-Match tuner and the result is about the same. Using a L-Match coil of different uH matters. A 126uH coil works good and (certain) higher inductance coils decrease reception. I have a 860uH coil. For shortwave frequencies it stops reception. For BC band it does help tune frequencies lower than 1mHz.
My variable capacitor is advertised as a 365pF, but it only goes to 220pF IF I connect / jumper 2 of the capacitor leads. When I use that capacitor with it's range from 8pF to 150pF most of the shortwave stations I receive are somewhere in the middle of the tuning range. Above and below that center tuning I hear almost nothing in the shortwave area.
It's no big issue for me to change coils because I made them in a way that I can slide off and change one or both inductances in under a minute.
Haven’t built a crystal radio set for 20 years… before that I was 9 years old when I built my first with my father, early 70’s.
I’m in the process of building your dual wiper, adjustable antenna design. There is an AM station with it’s antennas about a mile from my house. The adjustable antenna will be a necessity for I’m sure the station will bleed over into other AM stations.
What is not clear to me is the exact size of this antenna coil in relationship to the tuning coil.
Is it a ratio or percentage of the tuning coil?
I’m using 22 ga wire and a 2.2” dia tube. Your calculator set at 531 uH yields 139 turns for the tuning coil. How many turns should the antenna coil be?
Many thanks and appreciation in advance. Viewed tons of videos on this and you are by far the best I’ve seen!
Yeah, I kind of glossed over that. The answer really depends on your antenna, but a "too high" number of turns is better, because the tuner wiper is essentially shorting out the unused windings. I think I used 40 on that radio and it works pretty well with my 2 antennas, a 10 meter center tapped and a 15 meter end fed wire.
@@tsbrownie thank you for your prompt reply, these unknown details keep me awake at night… Giving the antenna coil “more turns than it needs” is the solid simple answer I searched high and low for. It makes a lot of sense.
Using your spoke wiper on the tower design as well. Going with stainless steel hardware & felt spring but using the necked half of a brass grommet as spoke eye contact with the fender washer and bushing for the wood screw threads.
Keeping it simple with a quick deployable line antenna for there is lightning about, I live in Florida… also going to give an in door loop antenna a try as well.
I’ll make a video and link it in a couple weeks to let you know how it all went.
Thank you again for your help and all your great videos!
@chrisupdegrave810 Sounds like you've got it nailed. Look forward to your video. The brass gromet should work well. I was going to do that, but none of the 4 hardware stores near me had them, and I wasn't going to wait.
@@tsbrownie got the radio build complete, antenna and ground rod. Works great but it’s swamped pretty much across the entire tuning coil with a local station that is about a mile away. There are only a couple stations besides that one and all rest on the high end of the band
Edited for clarification and spelling typos: his is the first homemade crystal radio I could hear (edit starting here) without the radio having any audio amplification built into the radio.
Oh your audio on your speaking volume is very good. I have a lot of videos I want to watch and their audio is just too low to hear.
No capacitor at all on this crystal radio !
The capacitance in this radio comes from the coil (along with the inductance of course) and the piezoelectric earphone. Adding more capacitance puts the resonance of the circuit out of the AM band.
@@tsbrownie Thank you. I understand. When I get a radio circuit to work I'm going to make the model with the L match..
@@southernexposure123 I think you'll like it. Even though the one in my video is just a crude experiment, it works better than any of my others!
@@tsbrownie Yes. If I remember right you suggest winding more turns on the demodulator coil than you put on the first one you made.. 170 turns on the diode coil and 30 to 55 turns on the grounded coii. As soon as I heard it play I drew that schematic and put it on my desk. I'll get some 14 or 16 GA wire from an old motor. It looks like aluminum wire. I know copper is easier to solder etc.
@@southernexposure123 I wish I could go back and update that. I was not clear that was a SWAG estimate. With a 3" coil, the left side does not need so many turns (ruclips.net/video/ejHk5tFeKHk/видео.html); it would only need 91 turns in theory. I might go with 100 as a starter and remove turns to tune it.
Thanks for explaining. Which oscilloscope did you use ?
I was going to ask the same thing. Great video by the way!!
He is not using an oscilloscope but a program on his computer that allows it to function as an oscilloscope. And I just asked him what program he is using and also about the connection from the radio to the computer.
Thank you!
@@heidobito7924 Thank you.
o boy...I just went to the age of 50 ( o yea) and remember my father always told me when I was a kid ..we gonna build that but it never came. Now my father has past away recentley memories are getting in my head and this is one of them...now I am gonna build that cristal radio. So 1 thing ( sorry..i'm not an electronic man). The first coil starts at the antenna...and it ends to a clip I see on your bord but its not connected to anything? The start of the 100 and ...50 turns or so is also not connected to anything ? I'm gonna have fun with this. Thank you for this perfect video.
In this radio, the 2 coils are NOT connected. The ends have no connection at all. Other radios will have connections on each end, not this one.
Look in the description for details. You should follow the tube and wire sizes carefully. Please let me know if you have questions.
I really like this design, the idea of the antenna match coil excellent.
Would any benefit be gained by adding a capacitor in parallel with radio coil?
I've watched your video on useless designs.
So is the one coil enough?
Those are some really profound questions. I have tried a variable capacitor (0 to 365 pF) in various configurations with this setup (hence all the taps) and never saw any benefit. I think it requires a significantly different design where the coil is just part of (maybe half) of the LC circuit, and that circuit is fed by both a circuit tunable to the antenna, and a filter in between to trap unwanted stations. I'm thinking about that and have taken the first few (baby) steps.
Thank You for your answer.
Have a Great Christmas.
@@johnmckee7937 You're welcome! Merry Christmas & Happy New Year!
If I put the Crystal Ear Piece at the end of a gramophone horn, would the sound 'normally' be strong enough to be audible? I was thinking of making a crystal set in a wooden box, with a wooden horn built into the lid. I have a V (or L) shaped 20M long wire antenna in the attic (attached to the beams through rubber bands) that I have used to pick up a signal before?
Would this setup work, be strong enough to produce sound?
I do have an Oscilloscope for testing for a signal.
That is an interesting idea. I can't say I have thought of it or heard of someone doing it before. In most ear pieces the ear part unscrews, so it would be an easy experiment for your to try. I'd start with a paper cone and see if that works before going on to something more time consuming. Let me know how it goes, I am curious.
Antenna is the first clip, then two more clips below the small coil are connected to wire under that part of the coil ?
The other two clips are "left over" from an earlier design / experiment. One is the end of the antenna coil. The other is the beginning of the radio coil.
I am making up some of the parts for a lesson to the granddaughters later this summer; I have two questions. My coils are 50 turns and 160 turns using 24 AWG magnet wire on a 3" dia form; after winding them I saw the comment on the antenna coil should be about 20 turns - I can easily remove about, say 25 turns - Why is a smaller coil more effective in this application than a larger one? Would you recommend I leave it until we assemble the parts to see if yhe crystal radio
will work?
A simple coil has 3 primary features that work in harmony to define the frequency they operate at: diameter, length, and turns per inch or cms (this is affected by wire thickness). If you change any or all of those much, you can change the tuning of the radio such that it is no longer in the AM band and you won't hear much if anything.
If you want to do your own coil, I made a video on some easy to use free apps.
ruclips.net/video/Fw9eb-aB-XU/видео.html
Or you can just play with these and see how changes to the coil affect the resonant frequency (the frequency the coil will work at).
If you have questions feel free to ask, I'll do my best to answer.
Can you show how you hooked up your Oscilloscope to it? I am just learning how to use one and am not sure how to probe it.
I am showing the voltage across the earphone. One probe is connected to one side, and the other probe is connected to the other side.
This is probably the best design of all. Unfortunately you do not explain how the two coils work. Is the smaller coil connected to the larger one? Or are the two coils separate but use the process of induction to transfer the signal between both coils. It looks like the ground and antenna are connected to the small coil and the diode and resister and ear piece is connected to the larger coil.
This is more about building it, the theory behind how it works is college level advanced analog electronics; most people are not interested in that. The short coil is the antenna coil: the antenna comes in one side and goes to ground at the other. It is "loosely coupled" to the other coil which is part of the tank circuit (resonant part of the circuit that sets the station you hear). In brief, the electromagnetic field created in the antenna coil is "shared" with the other coil (you've probably seen the field lines when someone sprinkles metal power on a piece of paper that's over a magnet. Those lines are shared.) It's basically an RF transformer. It helps create a cleaner impedance match with the antenna.
I once came across a diagram for crystal radio that had transistor boost amplification make it a bit louder and the transistor was supposed to be powered by radio waves so it was still free powered.
I wanted to try a build one to see if it worked any good but lost track of diagram.
If I recall, the channel called "BillyDIY" has a couple such radios. I tried searching "BillyDIY crystal radio transistor" but came up with nothing. I don't think he used the word transistor in the title, more like mosfet or some other.
@@tsbrownie the guy ' glasslinger ' who builds vacuum tubes from scratch had a nice vacuum tube amplified crystal radio in one of his videos.
The radio seemed extremely good at station selection even if it didn't have the amplification and it used a variable capacitor.
@@michaelszczys8316 Capacitivly tuned radios work and work well, but they are fussier and harder to make. I have a video on one style I found in an ancient radio magazine, and it's not as loud, but the sound is very clear and it has good discrimination.
Hello! I came here from your other video on how to make crystal radio. It's amazing how it all works. Darn, wish they would consider it playing in tune. Where do you connect the wires to produce effect?
Again. Thanks for sharing!
What do you mean "playing in tune"? I don't understand.
@@tsbrownie I want to hear more if it's possible, or how the effects begin to play. Why other videos connect it in waterpipe?
RUclips will not allow me to play other people's content including TV and radio for more than a few seconds. They remove my videos if I do.
Hello i don't know if your still building radios or not, But i building one something like this with a antenna coil. when you was explaining the antenna coil., Does it connect to the radio coil? ( what i mean both coil is one? ) but with a space between them?
There are both styles. I have radio videos for each. This radio is 2 individual coils. Yes I am still building, I am working on one right now.
Can we use a piezo speaker for this instead of a earphone?
In theory yes, but I can't say for sure because I have never tried it.
Where did you get the nice blue-colored 2-3/8" O.D. tubing? A plumber gave me a short piece years ago, he thought it was used for sprinkler systems. I've looked all over for it. Makes a pretty coil form.
It's been a long time. I think it's left over from the plumber who did some drain work for the neighbor.
@@tsbrownie I've been using some 2" OD plastic. Only about 1/16"wall thickness. Thinner than sch. 30. Perfect. Cheap where vacuum shops install central vac systems.
@@Jomatsch The wall thickness is not critical, it just makes it stronger. My first radio had a cardboard tube and was crushed by accident. A lot of winding work lost!
@@tsbrownie My first coil in 7th grade was wound on a piece of bamboo with wire from an old washing machine motor.
What is the gauge of the wire? If 1" pvc is used with the same length/or longer, will it work?
How about using a cylindrical magnetic inside the coil "pipe"?
All of the specifications are listed in the description, including pipe and wire sizes. I have a video on how to design your own coil using free software on the internet: ruclips.net/video/Fw9eb-aB-XU/видео.html
@@tsbrownie oh.. Ok thank you sir.
So, what are you grounding to, and you don't need an external antenna anymore since your coil and other wiper replaces that?
I am grounded to the steel in the house. A significant antenna is required, that's where the power is coming from. The coil is part of a resonant circuit.
What is the diameter of blue tube, what is the gauge of coil wire, ,how many turn we need to wound
All the details are listed in the description, from materials to construction. If something is missing or unclear, let me know.
signal so loud from this setup have you tried lighting an led with those outputs?
Yes, I have several videos doing that.
@@tsbrownie ok 10-four copycats proceeding to location...
Would the output lead being at the same end, place adjacent to each other be better or not. On this build they or at opposite ends.
I have a video on one like that, but this one is about a third louder.
@@tsbrownie I'm "coil crazy" and have built many oscillators. Have posted a few experiments. Thanks for the info. wound this one last night.
@@tsbrownie what grit sandpaper is used to expose the coil contact area for the slider.
600 grit?
@@tribulationcoming Any type that is pretty fine and will not damage the copper.
@@tribulationcoming Do you have a link?
What's the maximum frequency you can tune with this radio? Is it possible to get up into any bands above the commercial broadcast band with what you have here?
It only works with AM and pretty strong signals. You can google things like RF spectrum or AM broadcast bands. There are others that ships use, ham radio operators use, etc. but I don't know if the signals would be strong enough. You'd need long antennas, an amplifier on the output, and be within tens of miles of the source to have a good chance of success.
@@tsbrownie Most shortwave radio stations still broadcast in AM, right? I know the signal would have to be pretty strong to induce in the coil, but there are signals strong enough...IF you get enough wire in the air. Oh well, I may just build one of your designs and be happy with regular broadcast.
@@jdschauss FM has become more popular and this will not work with FM. (Some countries have replaced their Am civilian broadcasts with FM.) You have a good strategy, start simple and work to more difficult.
@@tsbrownie Oh, I know it's AM only. Again, I was just wondering specifically about 49 meters, but it looks like it may be too difficult a project and the end result may be disappointing. Thanks anyway.
Where about in the circuit would I place a variable capacitor?
and how many windings do you recommend on the left sided coil?
@@rustyshackleford8286 Around 20. I have too many on this one.
This does not use a cap. That would require a whole different coil and circuit.I have videos on cap types.
@@tsbrownieFor your design I am wondering if a 2 and a half inch postal tube work and if I can replace the Wipers with Taps?
and is your design for a crystal radio a better choice than this one ruclips.net/video/mubvsqFrE88/видео.html ?
I am trying to figure out which one would give the best results.... Very sorry for asking more questions, I'll try to make these the last.
Many thanks for your responses
I just uploaded a video with a link to this video of yours. It'll take maybe a few hours to process to high quality and for me to make it public as I also have a few chores to complete.
My new video won't be up long before it gathers an unwanted advertisement and I'll hide it by marking it a private video.
IF you see any value to the information feel free to make the information available with your own video on the same subject. I don't require being named as the source.
As soon as I make that video private I'll delete this comment.
Thanks for your time and the information you share.
ruclips.net/video/bjYXXlsU52U/видео.html
Thanks for the heads up. That's a very interesting experimentation rig you have there. Lots of flexibility without having to create all new base boards. I will have to look into the short wave thing. Perhaps the variometer's lower inductance will be a natural fit.
@@tsbrownieYou're welcome. Right. The lower inductance coils are the key to shortwave. the same might apply to the L-Match. I haven't yet tried extremely low inductance coils. And with the 14uH coil I didn't verify hearing any frequencies above 6.115 mHz.
I did see a video that heard diy CB radio receiver, but the same tuning heard a lot of the channels all at the same time. It was near 100% cross talk.
Your interpretation of variometer is different than my first thought, but I understand the premise. Good work.
Like my Telefunken Detektor...
I have a bunch of 47K resistors, will these work with this design?
It might. Give it a try. If the sound is too quiet or has pops in it, go with a lower value.
Do I also need to put the taps in?
@chris mead I was experimenting on length of the coil and where the ground and antenna might attach. No they are not necessary for normal operation.
@@tsbrownie I found 2w 30k resistors, will those work?
@@chrismead1464 They will likely work better than the 47k ohm resistors. Give it a try. Crystal radio is a lot about experimenting, seeing what works, and what does not.
The only pipe I can find is 3.5” on the outside… is that ok?
You have to recalculate the coil parameters. There are excellent websites where you can put in the data and get out the parameters. This is a good one: coil32.net/online-calculators/one-layer-coil-calculator.html
I have a video on the app. If I recall, the target inductance is around 520 to 620 microHenry.
@@tsbrownie OK, from that app i'm showing on a 3.5" core, i need 73.277 turns to get 520uH. What happens if there are more turns than that?
@@joel6221 Just found your comment. More turns = more inductance.
What power source do you use?
100% of the power is from the radio signal.
Are there any alternative for a crystal earpiece?
@@sergei8802 Not really good alternatives. I have a video on connecting a battery powered amplifier, but that requires a battery and defeats the purpose of a no-battery radio.
Did it work without diode？
No, they require some type of rectification. A diode, galena crystal, etc.
Sir which diode use in this radio
1n34a. Details are in the description.
Sir pls send photo this diode
Diode is not proper see in video
@@chemistry_with_yash-247 Please watch this video. It uses all the same parts.
ruclips.net/video/mt-s7pf-U5Q/видео.html
The ear piece I made with a crystal out of a microwave. Every microwave has one. It’s a black plastic part, and on one side round, and the other side square. On one side where you see like thin cardboard paper, I glued a 2 inch long 5/8 pvc pipe. You can also use the cover of a crazy glue tube. Make sure to cut the tube, so it’s open on both sides. Just hold the tube to your ear and listen to the sound of a station you’ll find. Simple, easy and it works perfect.!! Enjoy.!!
Before sticking it in your ear, make sure there are no nasty insects in it. I live in the tropics and ants, tiny scorpions, etc etc love to hide in it…ha..yaiks.!!
To hear a station louder, slide a piece of ferrite on a bamboo stick into the pvc pipe with the magnet wire coils around it. Slide it up and down if you find a station.
Greetings from the Dutch ABC Caribbean islands.!!
Hello brownie
I've uploaded more videos
My best dx Oman 1600 Miles away
And of my apartment
Please watch
Interesting. I looked up the radio you are using, the NM0S Discovery. Very nice!
The purchase link on his website is broken. Hope he fixes it.
@@tsbrownie yeah i found on ebay for 65 dollars last one
I sent him email telling him I'd like to buy another
He never replied
Very sensitive and selective!
Read my comments from all videos to see what my antenna is etc
Thanks for watching
BTW i need order the wooden box from hobby lobby for radio
Next time I'm in usa
@@tsbrownie I just sent him another email to i different address
I'll give update if he replies
The parts add up to close to 90 dollars
If purchased separately
So it's a good value for money
@@tsbrownie I got an email from nm0s
He said he will have them in stock in a few weeks
Great radio
He has web site
I can't post here yt will censor
@@baikushex0et682 OK, thanks. Will check.