... Beautiful and clear. Thank you.... In the late forties, I was sitting on the ground, leaning against a galvanized Iron Gate. It started receiving a clear radio signal. I think it must have been the zinc crystals in the galvanizing. This event seemed almost like a miracle, to 9 year old me.
I was cultivating with a tractor out in no where and started clearly hearing a station. Nobody else around for miles. I can only figure it was thru my tooth fillings.
1) The radio frequency's too fast to notice even if you were to make it turn a light on and off or make a sound. You can calculate it roughly by measuring or calculating the capacitance of the capacitor and the inductance of the coil and using those in the the formula for the resonant frequency. You'll have to look up the formulas for how to calculate the capacitance of a cylindrical capacitor and the inductance but you can see the rest in my How a Crystal Radio Works video starting at 3:36.
Ahh the Archer magnet wire set. Brings back such good memories. And Science Fair kits... O Radio Shack you will be missed. What they charge for those crystal earphones these days is highway robbery. They were commodity items when I was a wee scientist.
+Gabriels Raitis Kuma No, an LED won't work. The voltage required to start the LED conducting is too high for the radio. And it has to be a germanium diode, not a silicon diode. PS. Your comment doesn't have a Reply button because your Google+ settings are set to not allow "Anyone" to comment on your public posts.
I bought the lowest voltage drop Schottky diode (0.29v @ 5mA) with very small leakage (within nanoamps) but I have not had luck so far. I suspect my crystal earpiece may have been damaged though.
RimstarOrg I can pick up noise around 700KHz, and it sounds exactly the same on a surround sound system on the AM tuner selection. I think it is my PS3 or TV tuner. Even the tuner cannot pick up any strong AM stations, so if this does work, it is not very sensitive. I have had a germanium diode many years ago and that worked, but a HV transient popped it.
The second end of the 90 turns coil is connected to the ground. I thing it’s not really required. The circuit will always gets completed through the tuning wiper.
Yes, only the wire that I showed bought from Radio Shack is magnet wire. But it's all copper wire, though some of it may have a silver colored coating on the copper. Magnet wire is just copper wire with a thin coating of enamel/resin for insulation. It's called "magnet" wire because it's often used for making electromagnets. There's nothing magnetic about the wire itself. The other wires I used either have a thicker plastic or rubber insulation on them. Having said that, you can use the magnet wire for all of it if that's all you have. The reason I used magnet wire specifically for the coil was because it has a thin insulation on it allowing the copper to be closer together. If I'd used plastic insulated wire for the coils then the copper would have been further apart. With the coils, the closer each turn of copper is, without having copper touching copper, the better.
Does creating an antenna coil in addition to the tuning coil require the use of a variable capacitor? In other words, if I don't have a variable capacitor in my circuit, will the tuning coil still benefit from having an adjacent antenna coil, and will this particular circuit still work? Or does this particular circuit REQUIRE the use of a variable capacitor?
This particular circuit doesn't require the variable capacitor, it just makes tuning a little easier. You do need a capacitor though, something around 355 picofarads. The antenna coil is there to help with selectivity i.e. to help with tuning into one radio station and tuning out others. If you don't have it, then you may get overlapping radio stations.
Hi, could you please tell me if the size of the wire used in the coils is important? or is it just the amount of turns? will any wire do for use as coils as long as there is the right number of turns on each?
Mymla Pretty much any size of wire will work, unless you're talking about really big diameter wire like 14 AWG or thicker. The amount of turns is important, but so is the overall length. Look up the formula for inductance of a coil and you'll see what things go into it. But if your wire isn't super thick then the length won't vary enough to matter.
Anyone have any advice? I built one of these but all I can get on it is Shortwave, even though there's some interesting listening there and it pulls in some of these stations reasonably well (especially considering I am getting stations on it as far away as Romania and China coming in clearly) I would like to pull in the local AM stations but no matter what coil or tuning cap I use it's always the same result.
CoolDudeClem Can you describe you coil and cap? Dimensions, number of turns, ... I can plug them into my spread sheet to get resonance frequency range.
RimstarOrg Ok, I'm not sure about the tuning cap I used, it's an old style "open" one I got from out of an old radio, the coil is very much like the one in your video, about 90 turns of magnet wire on a 5cm diameter cardboard tube and about 53 mm long. I don't know what gauge wire I used.
CoolDudeClem Hmmm... Your coil does sound the same as mine, but without knowing the capacitance range of your tuning cap I can't compute resonant frequency range.
Just throwing out an ideal here... couldn't this be built (perhaps on a larger scale) and then bridged to a 12V capacitor, then to a 12V car battery. That could ensure the battery would maintain a consistant charge. Then by hooking up the battery to a Grid-tie inverter (DC to AC) then the power gets shipped back out to the grid. Much the same as how solar panels charge a car battery using the UV radiation, then running the battery (or bank of batteries) through an inverter and sening it back to the grid (or using some/all of the power that is absorbed, resulting in a lower daw fom the power company.
Theoretically, yes, it could be built on a larger scale and produce large amounts of power. Practically, no. The crystal radio's output is largely dependent on the length of the antenna and how close and powerful the radio station is. With a few 100 foot long antenna you could light an LED, so two such antennas would give twice the power but that's still not much.
Well, okay... I was just thinking of something along the lines of Tesla's Radiant Energy Patient, tuning to some local radio station (yeah I know.. I'd have to be careful about violating some unknown US FCC laws though.) Maybe you could use this "tuning" (like a ham radio) and increase the available power source for it by adding amperage that is charged from say... a grounding rod connected to capacitors that could be charged from the earth's magnet pull - like a ground sourced Tesla receiver. Hmmmm , now I'm going to have to try toying with some ideals and scarp steal rods, copper coils, and leftover computer components from an old Commodore 64 computer I had back in the 80s (uhhhh can anyone say 'RETRO'?) LOL!
wilwad if a war came along I'd be on the front line im a decent bloke fairly and I get well Larry wen Apple look at me funny down at the pub. I bounce em round like bunnies I've never broke a law in mi life and if a war came along I'd be on the front.line wig the best of em
That is a very very bad idea. Anyone who activates a transmitter after WWIII, will immediately receive a back up nuclear missile on their head. Radio silence will keep you alive.
A foxhole radio is also a crystal radio. There are many, many variations. A foxhole radio usually uses a razor blade and a pencil for the diode, instead of the semiconductor one I've used here. I show how to do that in my "Make Razor Blade Diode for Crystal Radio/Foxhole Radio" video (see the link in the description below this video.) Basically a foxhole radio uses less off-the-shelf parts since there aren't any in a foxhole.
It is called Radio Trench if the ingredients are truly made by yourself and obtained from the local area (such as razors and pencils), usually called a crystal radio because the crystal radio circuit is obtained from a shop/commercial crystal radio. It's called a foxhole radio because... Was it made in a foxhole during the war, or because its structure resembles a tunnel (tube)?
Very well done, Rimstar! It looks very primitive, but then the idea is to encourage people to try, and I think this is one of the best videos I have seen in that regard. The capacitor for the volume control is a very nice touch! Thanks for the time an effort you took to make this excellent and instructive video!
They are still online, but it's not the same. In the 70's they had most of what you needed and knowledgeable employees. Towards the end of their retail stores, they had nothing, and their employees didn't know the first thing about electronics.
Yes, you can use a variable capacitor. To match the coil in this video the capacitor should be in the range 40 picofarads to 355 picofarads if you want to tune in the whole AM radio frequency range.
The purpose of the short one is to be an inductor. It's inducing current in the longer one. The purpose of the longer one is to resonate with the capacitor at the tuned radio frequency. You might be interested in watching my "How a Crystal Radio Works" video, which goes into all that in great detail and with animations. There's a link to it in the description below this video.
A number of ways. Use a longer antenna. Make sure you have a good ground. Decrease the space between the two coils, though that may cause more interference between radio stations. You could also add an amplifier (e.g. one powered by a battery) but then it would no longer be considered a crystal radio since a crystal radio is one which is powered solely by the incoming radio waves.
There isn't much power here. With a long enough antenna or a strong radio station nearby, you can power a single LED. And you still need a radio station somewhere to use electricity to transmit the radio signal in the first place.
The crystal radio project is great for the younger generation, just I gone to the 1960s period when I was 10 years old I made this project, It was a great Joy to listen, to local radio station broadcast. Now I am 64 years old. Thanks for up loading you and You Tube.Now our younger generation should know how the radio works and be good at fundamentals of electronics.
Reminds me of when I made my first crystal set radio receiver in 1956 in Ontario Canada. Your video brought back some wonderful memories. I went on to build Televisions, HAM radio stations, Signal Direction Finders and eventually Computers. Thank you for sharing.
The name, Crystal radio, is mostly historical. Instead of a modern diode people used to use actual rock crystals, like galena, and touch it with the tip of a bare wire. This was called a cat's whisker in case you want to look it up. Some people still do that but I've haven't tried it yet. And I already have a video explaining how it works. See the description below this video for a link to my very detailed "How a Crystal Radio Works" video or find it on my channel page.
I swear, winding the coil is the most difficult and painstaking part. Especially if you never did that before. Took me a while to find the proper way of winding it and making each turn nicely and the wire ending up sitting close together. So satisfying when it's completely wound and ready to be prepared for the next steps.
A diode is something that allows electrons to flow through it in one direction only. So if your power source is one that make electrons move back and forth in the wire but you have a section of your circuit where you want electrons to go in one direction only, then you'd insert a diode in that section. It's called a "crystal" radio because people used to make the diode by touching a Galena rock crystal with the tip of a wire. Nowadays, a modern semiconductor diode is used instead.
Originally the diode was often a galena crystal and the sharp tip of a wire or metal object pressed was against it until a sound was heard. Electrical contact to this diode was made with the crystal and the wire. Then when modern commercial diodes came along, most people switched to using those instead. Nowadays, a crystal radio is defined as a radio that gets its power from the incoming radio waves.
I have to do that too sometimes. Usually I check all my connections, including my ground connection, and then I don't have to. I suspect two possibilities, that doing so changes the capacitance or grounds the foil.
I can't believe what I see. Just genious. I love how you build all this beautiful things starting from scratch. Well...I should say way less than scratch! I've never seen anybody making a capacitor that way. Could you please answer my question? Please I'm very inquiring: How the hell is the circuit removing the carrier wave from the audio signal wave? I suppose it's impossible to do that on an FM signal using such a simple circuit so I think the input signal you're receiving must be AM. But still, I can't see any LP filter or anything else to remove the carrier wave. How is the circuit doing that? Thank you again for all the knowledge, entertainment and ispiration you give to me.
That's a neat question, because the answer is so sneaky. :) The first obvious thing is that the diode chops off one polarity of the wave. Next, the piezoelectric crystal in the earpiece can't respond fast enough to each peak and zeroing of the carrier wave, so it responds slowly to the peaks only. The result is that the earpiece keeps up only with the audio wave. You can see this illustrated in my "How a Crystal Radio Works" video ruclips.net/video/0-PParSmwtE/видео.html at around 9:27.
I'm sorry, I found the explanation video just after I posted the question, now it's all perfectly clear. Thanks a lot, really. I was looking for a simple RF receiver but I just couldn't find a very basic one to understand, now I did, thank you again :)
You can reduce the size of the coil using a cylindrical ferrite core instead. It's around 1cm or 1/2inch in diameter. You can make a smaller capacitor using double sided copper cladding board. I show on of those capacitors in my "Crystal Radio Troubleshooting and Tips" video (there's a link to the it in the description below this video.) You can also buy smaller commercially made air core variable capacitors. I give a link in the description to midnightscience's website if you want to buy one.
The capacitor and coil are both used for tuning. They form what's called an LC network. L represents the coil (actually the coil's inductance) and C represents the capacitor's capacitance. When the inductance and capacitance are adjusted just right for a particular radio station, then the coil and capacitor resonate with each other, exchanging energy back and forth. The frequency they resonate at is the radio station's frequency. See my "How a Crystal Radio Works" video for more.
Wow ! Relived my childhood. Mine was a simpler one. I used to detach the earpiece of our chunky old telephone. Attach the two ends of a galena crystal to the two electrodes of the earpiece. connect the earth and aerial to each of those electrodes and enjoy the strongest available medium wave. The ground rule was, got to replace the ear piece before Dad gets home
What great memories...I did hours of listening on just a diode and earphone. And on tuned sets I DXed other states at night and even shortwave broadcasts.
Jumpstart Jimbo: Have you uploaded the video about this method? I have a faint memory my elder brother did it in the way you mentioned. We used to listen to the local radio station so clearly. That was 70 years back when I was a small kid. I saw the crystal (so he said, there was no diode or any other thing except the telephone receiver which he bought from the Calcutta second hand market) and with a slider (that is the wiper) we can tune in the radio station. Will you please do a video about this method. I believe many like me will be interested about it and they will be benefitted . Please do it and upload the video if possible. I want tp make like this in memory of my elder brother who is no more in this world. He had curiosity things like this.
I never thought to look in an old smoke alarm. Thanks! They definitely sound like peizo buzzers. And yes, this coil and capacitor are for tuning in 540kHz to 1.6MHz. I'm away from my own computer this week otherwise I could easily calculate what's needed for 198kHz but I'm pretty sure you need more turns.
Cool! Be sure to check out the playlist. ruclips.net/p/PLFsZmHTZL-zlSltC6ELZW9PK4ks7wgPRz I made a bunch of related videos on the topic, including troubleshooting and tips and how-it-works.
Great Vid, short and too the point!!! I made one when I was a kid, my dad knew eletronics, and tried to teach me, at the time my dad had a heath kit 2 m reciever that was soo cool!! I still dont know much about elertonics, and was wondering ???... If you could use a modern day germanium diode, I bought a kit from china for my raspberry pi's to start learning stuff, and it has a lot of germanium diode's... but not 1n34....
If they're germanium diodes then they should work. Are you sure they're germanium diodes though. Most diodes that you see these days are silicon diodes and those require a more power signal from the radio waves, usually meaning an antenna a hundred or more feet or being very close to the radio station so that you get a strong signal..
@@RimstarOrg Thanks for the info, I am not sure of anything!!... ha ha ha.... all I know for sure is the diodes I have look like the one you showed in the video.... but smaller
Thank you. This is brilliant. I am researching for a novel set in a WW2 prisoner of war camp, where I've been told they had a crystal radio, built with smuggled parts. I couldn't quite understand how they could have built it, but now I can see the simplicity of it. This has given me everything I need to know! I also really liked your snappy delivery and the way you had filmed the video. Thank you.
Indeed they did and more: look up Roy Kilminster's site, he was a prisoner in Stalag Luft I and they had a radio built with smuggled tubes. He was the keeper of the radio and has pictures of it and how they hid it in a wall.
I am 73 and have two crystal radios one I made with a razor blade as the tuner in stead of the wiper . I can get three station one is 35 miles away wwva large powered station
Yeah, remember that trick. Glue a razor blade flat on a wooden board, fix the head of a safety pin near it with a nail, touch the sharp point of the pin vertically on the flat surface of the blade. That'll work as a crude diode
I don't know of any way to do it using a transformer, not that that means there isn't one, but I've made two amplifiers by other ways. One amplifies it for the earpiece and the other amplifies it so you can listen using a loudspeaker. See my "How to Make Amplifier for Crystal Radio Earphone" and "How to Make Crystal Radio Amplifier for Speaker" videos. There are links to them in the description below this video.
I don't know if you will manage to make them. If you have 6 months and you start right away, then I don't see why not. Depending on how old you are and how much experience you have building things then you might need a little help from your parents or teacher but 6 months is a long time if you don't wait until the last minute. The cost should be less than $50 US approximately. Feel free to ask questions here too.
Those were the days of learning about radios and how they work and how to build them. So many youngsters of todays generation could learn so much from videos like this, but many won't be interested because of computer rubbish. Thank you for this video.
Typically, no, a silicon diode won't work. For that you either need a very long, straight antenna (over 100 feet) or to be next to a powerful radio station. And yes, you can use less turns. You just may have more overlapping stations since you're compressing them into a smaller length of coil for tuning purposes.
I show another DIY design in my crystal radio tips and tricks video ruclips.net/video/HZZmKZJrIW0/видео.html. I have some links to where you can buy on in the video description.
Sir I'm working on this project and I have two questions 1. can we have any other option for grounding because it may be dangerous and I want to make it portable. 2. Can we use one earphones piece for sound will it be much sensitive to sound. Sir plz help its my project
There is no crystal. In the original crystal radios from the early 1900s they did use a crystal instead of the modern diode and that's where they got the name crystal radio. But these days a crystal radio is any radio that gets its power from the incoming radio waves.
I'm actually working on a video explaining how many turns now, but it won't be out for a week or so. The capacitor and coil form an LC resonant circuit. It doesn't have to do with wavelength the way you seem to be thinking about it though. In the meantime, I have some calculators here rimstar.org/science_electronics_projects/lc_circuit_aka_tank_or_resonant_circuit.htm for working out the right coil. I also talk explain it in my How a Crystal Radio Works video ruclips.net/video/0-PParSmwtE/видео.html.
Did you mean FM transmitter and receiver? rf means Radio Frequency which is from 3kHz to 300GHz. Both AM and FM transmit using frequencies in that radio frequency range. A crystal radio is an AM receiver and I already have a video "How to Make AM Radio Transmitter" (see the link in the description below this video.) FM transmitter and receiver are both high on my todo list but I don't know when I'll get to them. It's a long list.
The only difference between a foxhole radio and an old style crystal radio is that the old style crystal radio used a galena rock crystal and a sharp wire for the diode and a foxhole radio used a razor blade and pencil for the diode. My video "Make Razor Blade Diode for Crystal Radio/Foxhole Radio" is a foxhole radio because it uses a razor blade and pencil. There's a link to it in the description below this video.
Yeah i too did that on the ends of each wire. However i would not recommend doing that instead of sanding off the coating layer for the wiper. You only wanna wear off the upper layer, not the whole coating all around the coil on that spot.
This video is a big motivation and knowledge source. Thank you so much for that. I am teaching a lab course and including this as the final project. So I had tried to make it as simple as possible and actually providing kits for every student. In the process, I have gathered the following thoughts: 1) Coil: I find the sliding option a bit challenging and intimidating, although I did get it to work. My modified design is a total of 65 turns, with a small loop at 40th turn. So there are 2 settings, 65 turns with the loop not touched, and 40 turns with the loop grounded. Between these 2 settings, the frequency range is quite good. After all, you just want to get some channels to show off, but not necessarily all the channels. 2) Capacitor: I tried to “improve” your design, but finally realized how good yours is. Thought of parallel plates that some people use, but bowing near enter is unavoidable, while your tube design has no such problem. I also tried other materials to make it more rigid than aluminum foil. I tried flashing materials (aluminum and galvanized steel) but they are too stiff and leave too much gap between the inner and outer tubes, so probably loosing some capacitance for the same size. I wound up using thicker aluminum foil available. I was also concerned about the contact by taping, but convinced myself that contact to capacitors is not that critical, since there is no DC current. 3) Speaker: This is more critical and difficult than I expected. Piezo earphone did not work for me, and it was a bit expensive ($7) and I returned it. Piezo buzzer (much cheaper) I could hear something but is quite faint, so hard to tune channels. I also tried piezo transducer, and it did not work. The best I used was a guitar amp, but not everybody has one. Next I will try are PC speaker and headphone (both suggested by your viewers). 4) Wish I could show a photo of my final project, but I did not see that option. Again thanks a million. It’s nice to see old school is kept and being pursued. I am retired and always wanted to do it. Well I finally did!
Thanks for sharing all that. I've had the same problem when teaching a class, having to find the cheapest and simplest way that works. So I can relate. I'm glad to hear it worked out.
Thanks. You can buy crystal earpieces online. See the description below this video for links. You can use piezo buzzers that you buy at electronics stores like Radio Shack. You can use disk piezo crystals taken from various things. See my "Make Crystal Earphone/Earpiece for Crystal Radio" video for taking one from a microwave oven. You can use normal earbuds. See my "Use Earbuds/Earphones with Crystal Radio" video for that. Links to the videos are in the description below this video.
No, the crystal radio can't receive FM. And you're right, if the nearest radio station is 100km away then the portable crystal radio won't work, at least I doubt it will. You can make your own AM transmitter. I show how in my recent video "How to Make Crystal Radio Amplifier for Speaker". There's a link to it in the description below this video. Just make sure your transmitter can't transmit very far so that you don't interfere with other radio stations.
How long is your antenna? 1N4148 is a silicon diode. That and the zener and avalanche diodes need more voltage to start conducting than mine with my three parallel 15 foot antennas. I'm guess either you're antenna is pretty long or you're near some powerful radio stations. Let me know so I'll know if I should add them to the list in the description below this video with a caveat.
1N4148 is a silicon diode. You need a germanium diode. I haven't tried it myself, but someone here reported it works if you use 5 silicon diodes in parallel, meaning connect all their striped sides together and all their non-striped sides together. You can't use normal speakers. You can use normal earbuds (like iPod earbuds for example) using the trick in my "Use Earbuds/Earphones with Crystal Radio" video. There's a link to it in the description below this video or see my channel page.
No, a crystal radio doesn't require batteries. It gets its power from the incoming radio waves themselves. That's what makes these so fun to work with. But it also means that unless you have a very long antenna and a good ground connection or a radio station nearby, then you'll either have trouble getting something or it will be very quiet. Plus, you'll usually need earphones to listen to it, not a speaker. Or you could add an amplifier circuit, but that's no longer a crystal radio :).
Two diodes in parallel in the same direction, side-by-side would help. A full wave rectifier wouldn't work. Do you mean as when you put the "phone on speaker" so everyone in the room can hear it? If so, you'll likely need an amplifier circuit. If you mean a piezo speaker in the listening end of a phone then just extract the crystal and use it as in the video. If an electromagnet type speaker then you might be able to use the trick I use in my "Use Earbuds/Earphones with Crystal Radio" video.
I'm glad to hear it worked. Are you sure you have a germanium diode? One reason a germanium diode is important for the particular crystal radio circuit is that germanium diodes are a bit leaky, which is needed for reasons explained in my How a Crystal Radio Works video. I suspect either you have a germanium diode and some current is leaking through the high resistance of your body, helping with the leakage, or you've a silicon diode and your body is providing the needed leakage. Just a guess.
A Schottky diode wouldn't normally work with this circuit. However, I haven't tried it myself but it's been reported below that 5 silicon diodes wired in parallel worked, possibly doing the same with Schottky diodes would work. I wouldn't guarantee it though. Parallel means all the ends with the stripes connected together and all the ends without the strips connected together and use where the diode normally goes.
One end of the antenna wire isn't connected to anything. The other end goes to the end of the 25 turn coil that is farthest from the 90 turn coil. See the diagram in the video at 0:24. Since it's the ground wire you're connecting to, you shouldn't have to switch on the extension box (I don't have an extension box to switch on anyway.) See my video "Crystal Radio Troubleshooting and Tips" for more about grounding. There's a link in the description below this video and on my channel page.
What is the diameter of your ferrite core? For one that's around 1cm in diameter you need only around 30 turns instead of the 90 ACCORDING TO MY CALCULATIONS. I haven't tried a ferrite core myself so I suggest more turns anyway to be safe. Having extra turns doesn't hurt if you have a tuning bar since everything after the tuning bar doesn't count. You might be able to use two coils if the ferrite and the coils are touching. How long is your antenna and what are you using for ground.
I just lay a long length of wire across my floor. Mine isn't very long, only around 3 meters, but I pick up a few nearby radio stations and a few that are a few hundred kilometers away. Most of the time I actually lay out three wires parallel to each other and connect them together at the radio. The diameter of wire (wire gauge) doesn't matter much. Longer is better. And if you have one radio station you always listen to, point the wire at that station if possible.
If you're getting fluctuating pitches and crackles with no external power source than the radio waves, then I suspect you're getting something, even if it's just a jumble of electromagnetic waves. I suspect you may need a better ground too. A butter knife in the ground doesn't give much good electrical contact. You could pour water over that spot to dampen the ground or bury a larger object. Normally a 6 foot rod is used. Google search "ground rod". But try your antenna first.
Ah, a few problems then. An 8 feet antenna isn't very long, unless you have radio stations nearby. I do and with my three parallel 15 foot antennas, the stations come in fairly quiet. Good innovation with your ground, hopefully it's enough in the ground. The wetter the ground the better. But I just checked 1n4148 and it's a silicon diode. With your short antenna, I'm doubting you'd get the voltage needed for the diode to conduct. Maybe try two or three in parallel or find a germanium diode.
I got mine on ebay. Germanium diodes are best. Other germanium diodes are 1N60, 1N91, 1N119, 1N270, 1N277, 1N283. You can also try two or three silicon diodes in parallel (all the striped end connected together and all the non-striped ends connected together.) I also recently uploaded a video showing how to use a razor blade and a pencil to make a diode but it didn't work great (see video link in the description below this video.) And it doesn't have to be magnet wire but it must be insulated.
A 3v piezo buzzer should work. Mine is 4v minimum, so yours requires even less voltage than mine. I'm assuming your buzzer comes in a black case with a hole in one side. Cut a plastic tube, like a pen, around 1 cm (1/2 inch) long and glue it over the hole, then you can better direct the sound into your ear. I find they're not as good as the commercial crystal earpieces, but they work. Maybe your problem is elsewhere? Check all connections. The longer the antenna the better. Us a good ground.
No, if doesn't matter what part the positive and negative terminals are connected. It doesn't matter which side of the capacitor is grounded as long as the circuit remains the same i.e. don't ground the diode. Touching it doesn't provide a good enough ground, although someone below said they had luck that way by wrapping aluminum foil around their finger and then connecting to the foil for ground, thereby contacting more skin surface area. How long is you antenna? The longer the better.
The configurations I know of are stretched out straight pointing at the radio station (if you know where it is) with the crystal radio at one end or with the crystal radio in the middle. Either that of coiled up in a large coil around 2 feet in diameter, with around 15 turns, with the crystal radio connected at one end and with the open end of the coil facing the radio station. For an example of coiled approach see my "Portable Crystal Radio using Loop Antenna and Pizza Box" video.
If you use a metal rod then that changes things a lot. What is the material of the rod? What is the diameter of the rod? Some quick, rough calculations for a steel or iron rod that's 1cm in diameter shows it needs only 30 turns and will be only 1.4 cm long. Your second question is kind of hard to answer since the meaning of reception is vague. One way to get less static is to increase the distance between the two coils but the volume will be less.
The 50km distance could be your problem. If the antenna is a coil like my pizza box portable crystal radio then it's not very powerful. You could try putting you hand on the aluminum foil of the capacitors, making sure to get lots of surface contact. Try it with the outer foil cylinder and then try it separately with the inner foil cylinder. Your hand will act as a ground.
Do you have any radio stations nearby? If yes, try pointing the antenna at them. How long is you antenna? The longer it is the better it'll work. Mine is 15 feet long, with three in parallel and I get only the nearby stations. The antenna should be stretched out in a straight line as much as possible. Do you have a good ground?
I don't know. They look identical to me based on the photos. I bought mine from midnightscience years ago at the same time I bought a bunch of books and one of their radios. They worked great until I broke them, but that was my doing (I opened one up out of curiosity and the other one I cracked by accident.)
I've no experience in sw so I can't give a good answer. I have tuned in 1.8MHz with the radio in this video though, but that still leaves a lot of sw. What you say about using a grounded stiff wire that moves over the coil so you can hear mw sounds right, and in fact isn't needed since the tuning bar in this radio is just that - it's grounded.
No, there isn't enough power to run the coils of an ordinary speaker. Well, unless you have a really long antenna. It's not the best but you can use ordinary earbuds if you add a small transformer. I explain how in my video "Use Earbuds/Earphones with Crystal". There's a link to it in the description below this video and you can find it on my channel page.
Much literature; especially the older pubs suggest using water pipes as a ground. That only works in older homes/buildings where iron pipe was used in the water supply. For many years, PVC has replaced metal pipe in home plumbing, and PVC is an insulator. The only thing in the house that will function as a ground is the ground terminal of an electric plug --- as you have done. Still, I'm afraid to recommend that given the number of people who don't know ground from hot and neutral. :(. I recommend driving a metal pipe a few feet into the ground for ground use.
You could also try a razor blade and pencil diode. I found it very hard to get working but it's another option. See my recent video "Make Razor Blade Diode for Crystal Radio/Foxhole Radio". There's a link to it in the description below this video and on my channel page.
Yes, the other end needs to be grounded. Without it being grounded it won't work as well. The ground provides an easy path for the electrons to take. See my video "How a Crystal Radio Works" at 0:40. There's a link to it in the description below this video or you can find it on my channel page.
Yes, but you'll have to add a transformer. To see the details watch my video "Use Earbuds/Earphones with Crystal Radio". There's a link to it in the description below this video and you can find it on my channel page. (I seem to have a video for everything :)).
If you're talking about the aluminum foil, it doesn't matter which side is up. The only difference between the shiny side of aluminum foil and the dull side is that one is shiny as a side effect of how it's made. There's no coating on either side.
The voltage difference comes from the incoming radio waves. The radio waves themselves are your power source. No battery is needed, unless you want to increase the volume by adding an amplifier. See my video "How a Crystal Radio Works" for more on this.
I don't have any way of measuring the inductance. The best I can do is calculate it and it ranges from 0 to 0.369 millihenries. I measure the capacitance in my "Crystal Radio Troubleshooting and Tips" video and it ranges from 0 to 640 picofarads.
The antenna doesn't need to be hung. I use 3 15 foot wires connected in parallel and run across my floor. Though if your floor is metal then there may be a problem. The higher up you go in the air the better, but mine works fine on my hardwood floor.
One way is to make a radio transmitter and transmit music to it. You can see me do it in my video "How to Make AM Radio Transmitter". There's a link to it in the description below this video.
... Beautiful and clear. Thank you.... In the late forties, I was sitting on the ground, leaning against a galvanized Iron Gate. It started receiving a clear radio signal. I think it must have been the zinc crystals in the galvanizing. This event seemed almost like a miracle, to 9 year old me.
I was cultivating with a tractor out in no where and started clearly hearing a station. Nobody else around for miles. I can only figure it was thru my tooth fillings.
Like in the 1940s? wow
@@martinkennard1669same thing happened to me in school after I got a new tooth filling.
Thank you! I am going to build this with my 12 year old son.
Great video, nicely explained and good to know that the radio can be built using junk materials.
1) The radio frequency's too fast to notice even if you were to make it turn a light on and off or make a sound. You can calculate it roughly by measuring or calculating the capacitance of the capacitor and the inductance of the coil and using those in the the formula for the resonant frequency. You'll have to look up the formulas for how to calculate the capacitance of a cylindrical capacitor and the inductance but you can see the rest in my How a Crystal Radio Works video starting at 3:36.
Yes, you can use a paper clip or anything metal that doesn't have an insulating coating on it.
Very interesting, I use to make heaps of Crystal radios when I was a kid. Haven't made one in ages.
Ahh the Archer magnet wire set. Brings back such good memories. And Science Fair kits... O Radio Shack you will be missed. What they charge for those crystal earphones these days is highway robbery. They were commodity items when I was a wee scientist.
+Gabriels Raitis Kuma No, an LED won't work. The voltage required to start the LED conducting is too high for the radio. And it has to be a germanium diode, not a silicon diode.
PS. Your comment doesn't have a Reply button because your Google+ settings are set to not allow "Anyone" to comment on your public posts.
Will an Schottky diode work also?
Some mentioned in the comments here that a low-barrier Schottky barrier might work. I haven't tried it myself.
I bought the lowest voltage drop Schottky diode (0.29v @ 5mA) with very small leakage (within nanoamps) but I have not had luck so far. I suspect my crystal earpiece may have been damaged though.
Thanks. Let me know if you do get it working. It would be nice to have confirmation.
RimstarOrg I can pick up noise around 700KHz, and it sounds exactly the same on a surround sound system on the AM tuner selection. I think it is my PS3 or TV tuner. Even the tuner cannot pick up any strong AM stations, so if this does work, it is not very sensitive. I have had a germanium diode many years ago and that worked, but a HV transient popped it.
Hi, You can use small PVC pipe and PVC glue to hold coil. It worked perfectly for me specially for coils which have gaps in between loops.
Chanaka Balasuriya Great! Thanks for letting us know.
The second end of the 90 turns coil is connected to the ground. I thing it’s not really required.
The circuit will always gets completed through the tuning wiper.
Hi! You can put a video in which show how to make a galena detector?
very impressive!
cool video thank you.
one question, why didn't you ground to a simple piece of copper pipe or wire.
ah Radio Shack -- the good ol days
I might not have quite catched it but- it is only the wire you bought from radioshack that is magnet wire, and the rest just ordinary copper wire?
Yes, only the wire that I showed bought from Radio Shack is magnet wire.
But it's all copper wire, though some of it may have a silver colored coating on the copper. Magnet wire is just copper wire with a thin coating of enamel/resin for insulation. It's called "magnet" wire because it's often used for making electromagnets. There's nothing magnetic about the wire itself. The other wires I used either have a thicker plastic or rubber insulation on them.
Having said that, you can use the magnet wire for all of it if that's all you have. The reason I used magnet wire specifically for the coil was because it has a thin insulation on it allowing the copper to be closer together. If I'd used plastic insulated wire for the coils then the copper would have been further apart. With the coils, the closer each turn of copper is, without having copper touching copper, the better.
Aaaah, I see!
So I guess I know what I'll have to get now ;) I simply MUST give it a try! It's so... Geeky and awesome :D
that's amazing!
Does creating an antenna coil in addition to the tuning coil require the use of a variable capacitor? In other words, if I don't have a variable capacitor in my circuit, will the tuning coil still benefit from having an adjacent antenna coil, and will this particular circuit still work? Or does this particular circuit REQUIRE the use of a variable capacitor?
This particular circuit doesn't require the variable capacitor, it just makes tuning a little easier. You do need a capacitor though, something around 355 picofarads.
The antenna coil is there to help with selectivity i.e. to help with tuning into one radio station and tuning out others. If you don't have it, then you may get overlapping radio stations.
Thank you. This is very helpful.
Hi, could you please tell me if the size of the wire used in the coils is important? or is it just the amount of turns? will any wire do for use as coils as long as there is the right number of turns on each?
Mymla Pretty much any size of wire will work, unless you're talking about really big diameter wire like 14 AWG or thicker. The amount of turns is important, but so is the overall length. Look up the formula for inductance of a coil and you'll see what things go into it. But if your wire isn't super thick then the length won't vary enough to matter.
Could we use the the 1N34a instead of 1N34 ?
Yes.
Anyone have any advice? I built one of these but all I can get on it is Shortwave, even though there's some interesting listening there and it pulls in some of these stations reasonably well (especially considering I am getting stations on it as far away as Romania and China coming in clearly) I would like to pull in the local AM stations but no matter what coil or tuning cap I use it's always the same result.
CoolDudeClem Can you describe you coil and cap? Dimensions, number of turns, ... I can plug them into my spread sheet to get resonance frequency range.
RimstarOrg
Ok, I'm not sure about the tuning cap I used, it's an old style "open" one I got from out of an old radio, the coil is very much like the one in your video, about 90 turns of magnet wire on a 5cm diameter cardboard tube and about 53 mm long. I don't know what gauge wire I used.
CoolDudeClem Hmmm... Your coil does sound the same as mine, but without knowing the capacitance range of your tuning cap I can't compute resonant frequency range.
Just throwing out an ideal here... couldn't this be built (perhaps on a larger scale) and then bridged to a 12V capacitor, then to a 12V car battery. That could ensure the battery would maintain a consistant charge. Then by hooking up the battery to a Grid-tie inverter (DC to AC) then the power gets shipped back out to the grid. Much the same as how solar panels charge a car battery using the UV radiation, then running the battery (or bank of batteries) through an inverter and sening it back to the grid (or using some/all of the power that is absorbed, resulting in a lower daw fom the power company.
Theoretically, yes, it could be built on a larger scale and produce large amounts of power. Practically, no. The crystal radio's output is largely dependent on the length of the antenna and how close and powerful the radio station is. With a few 100 foot long antenna you could light an LED, so two such antennas would give twice the power but that's still not much.
Well, okay... I was just thinking of something along the lines of Tesla's Radiant Energy Patient, tuning to some local radio station (yeah I know.. I'd have to be careful about violating some unknown US FCC laws though.) Maybe you could use this "tuning" (like a ham radio) and increase the available power source for it by adding amperage that is charged from say... a grounding rod connected to capacitors that could be charged from the earth's magnet pull - like a ground sourced Tesla receiver.
Hmmmm , now I'm going to have to try toying with some ideals and scarp steal rods, copper coils, and leftover computer components from an old Commodore 64 computer I had back in the 80s (uhhhh can anyone say 'RETRO'?) LOL!
Everybody please pay attention, we will be using these again after WW3
wilwad if a war came along I'd be on the front line im a decent bloke fairly and I get well Larry wen Apple look at me funny down at the pub. I bounce em round like bunnies I've never broke a law in mi life and if a war came along I'd be on the front.line wig the best of em
*british* 100
Probably...and since the internet might get destroyed too, those who posses this knowledge will be the new radio stars. :D
That is a very very bad idea. Anyone who activates a transmitter after WWIII, will immediately receive a back up nuclear missile on their head. Radio silence will keep you alive.
@@videolabguy after it ends tho
A foxhole radio is also a crystal radio. There are many, many variations. A foxhole radio usually uses a razor blade and a pencil for the diode, instead of the semiconductor one I've used here. I show how to do that in my "Make Razor Blade Diode for Crystal Radio/Foxhole Radio" video (see the link in the description below this video.) Basically a foxhole radio uses less off-the-shelf parts since there aren't any in a foxhole.
I made a foxhole radio as a kid, much older now.
It is called Radio Trench if the ingredients are truly made by yourself and obtained from the local area (such as razors and pencils),
usually called a crystal radio because the crystal radio circuit is obtained from a shop/commercial crystal radio.
It's called a foxhole radio because... Was it made in a foxhole during the war, or because its structure resembles a tunnel (tube)?
The power source is the incoming radio waves themselves. No battery, no plugging into the wall socket.
exactly, this video is not about a crystal radio.
𝙾𝚔,
𝙽𝚘 𝚘𝚗𝚎 𝚊𝚜𝚔𝚎𝚍 𝚎𝚒𝚗𝚜𝚝𝚎𝚒𝚗
Very well done, Rimstar! It looks very primitive, but then the idea is to encourage people to try, and I think this is one of the best videos I have seen in that regard. The capacitor for the volume control is a very nice touch! Thanks for the time an effort you took to make this excellent and instructive video!
If I had a son/daughter I would watch this with them and build a radio. Builds bonds and teaches them things. Amazing vid, thanks.
I'd do that
Can I be your son/daughter?
Build my first radio, very similar to this, with my dad when I was young, great memory.
honest reaction : Fascinated 😆😃😄✨✨
R.i.p radio shack
Lol
i remember those days.
Absolutely I've got hundreds of old radios for parts
Long live radio shacks.
They are still online, but it's not the same. In the 70's they had most of what you needed and knowledgeable employees. Towards the end of their retail stores, they had nothing, and their employees didn't know the first thing about electronics.
Yes, you can use a variable capacitor. To match the coil in this video the capacitor should be in the range 40 picofarads to 355 picofarads if you want to tune in the whole AM radio frequency range.
Can this pick up Shortwave?
The purpose of the short one is to be an inductor. It's inducing current in the longer one. The purpose of the longer one is to resonate with the capacitor at the tuned radio frequency. You might be interested in watching my "How a Crystal Radio Works" video, which goes into all that in great detail and with animations. There's a link to it in the description below this video.
A number of ways. Use a longer antenna. Make sure you have a good ground. Decrease the space between the two coils, though that may cause more interference between radio stations. You could also add an amplifier (e.g. one powered by a battery) but then it would no longer be considered a crystal radio since a crystal radio is one which is powered solely by the incoming radio waves.
Is it the answer to wireless and free electricity
There isn't much power here. With a long enough antenna or a strong radio station nearby, you can power a single LED. And you still need a radio station somewhere to use electricity to transmit the radio signal in the first place.
cant believe how simple this is, thank you for taking the time to make this video and showing us this cool experiment :D
I built one when I was 10, 62 years ago. I was a little more carful in construction but the same circuit. thanks for the memories.
The crystal radio project is great for the younger generation, just I gone to the 1960s period when I was 10 years old I made this project, It was a great Joy to listen, to local radio station broadcast. Now I am 64 years old. Thanks for up loading you and You Tube.Now our younger generation should know how the radio works and be good at fundamentals of electronics.
Reminds me of when I made my first crystal set radio receiver in 1956 in Ontario Canada. Your video brought back some wonderful memories. I went on to build Televisions, HAM radio stations, Signal Direction Finders and eventually Computers. Thank you for sharing.
I made my first crystal radio, when I was 9 years old, I had a comic book instructed you how to make one. And it worked great at the time.
""Superboy's Workshop" How to Make a Razor-Blade Radio!" Last reprinted in Four Star Spectacular #4, Oct. 1976!
Probably comic book page is :i.pinimg.com/originals/b7/cc/a3/b7cca337dc4a239b60f9aeab203877e8.jpg
The name, Crystal radio, is mostly historical. Instead of a modern diode people used to use actual rock crystals, like galena, and touch it with the tip of a bare wire. This was called a cat's whisker in case you want to look it up. Some people still do that but I've haven't tried it yet.
And I already have a video explaining how it works. See the description below this video for a link to my very detailed "How a Crystal Radio Works" video or find it on my channel page.
I swear, winding the coil is the most difficult and painstaking part. Especially if you never did that before. Took me a while to find the proper way of winding it and making each turn nicely and the wire ending up sitting close together. So satisfying when it's completely wound and ready to be prepared for the next steps.
A diode is something that allows electrons to flow through it in one direction only. So if your power source is one that make electrons move back and forth in the wire but you have a section of your circuit where you want electrons to go in one direction only, then you'd insert a diode in that section. It's called a "crystal" radio because people used to make the diode by touching a Galena rock crystal with the tip of a wire. Nowadays, a modern semiconductor diode is used instead.
You stoopid
𝙱𝚛𝚞𝚑
𝚈𝚎𝚊, 𝚍𝚞𝚑
I have no ground connection in my home what I will do?????please five me answer
@@bhavanabenrathod2706 pretty much all homes have a ground. You can also use exposed copper or gas plumbing for a ground.
I have always enjoyed making crystal radio's ... we used to use a germanium crystal. This is an awesome tutorial ... the best I have seen !!!
Originally the diode was often a galena crystal and the sharp tip of a wire or metal object pressed was against it until a sound was heard. Electrical contact to this diode was made with the crystal and the wire. Then when modern commercial diodes came along, most people switched to using those instead. Nowadays, a crystal radio is defined as a radio that gets its power from the incoming radio waves.
I have to do that too sometimes. Usually I check all my connections, including my ground connection, and then I don't have to. I suspect two possibilities, that doing so changes the capacitance or grounds the foil.
Ah, I see what you mean now. I'll be doing a variometer when I use my ferrite core, I just was familiar with the term. Thanks.
I can't believe what I see. Just genious. I love how you build all this beautiful things starting from scratch. Well...I should say way less than scratch! I've never seen anybody making a capacitor that way.
Could you please answer my question? Please I'm very inquiring: How the hell is the circuit removing the carrier wave from the audio signal wave? I suppose it's impossible to do that on an FM signal using such a simple circuit so I think the input signal you're receiving must be AM. But still, I can't see any LP filter or anything else to remove the carrier wave. How is the circuit doing that?
Thank you again for all the knowledge, entertainment and ispiration you give to me.
That's a neat question, because the answer is so sneaky. :) The first obvious thing is that the diode chops off one polarity of the wave. Next, the piezoelectric crystal in the earpiece can't respond fast enough to each peak and zeroing of the carrier wave, so it responds slowly to the peaks only. The result is that the earpiece keeps up only with the audio wave. You can see this illustrated in my "How a Crystal Radio Works" video ruclips.net/video/0-PParSmwtE/видео.html at around 9:27.
I'm sorry, I found the explanation video just after I posted the question, now it's all perfectly clear. Thanks a lot, really. I was looking for a simple RF receiver but I just couldn't find a very basic one to understand, now I did, thank you again :)
Thanks for the recommendation. I find Crystal Radio: History, Fundamentals, and Design by P.A. Kinzie to be very good too.
You can reduce the size of the coil using a cylindrical ferrite core instead. It's around 1cm or 1/2inch in diameter. You can make a smaller capacitor using double sided copper cladding board. I show on of those capacitors in my "Crystal Radio Troubleshooting and Tips" video (there's a link to the it in the description below this video.) You can also buy smaller commercially made air core variable capacitors. I give a link in the description to midnightscience's website if you want to buy one.
The capacitor and coil are both used for tuning. They form what's called an LC network. L represents the coil (actually the coil's inductance) and C represents the capacitor's capacitance. When the inductance and capacitance are adjusted just right for a particular radio station, then the coil and capacitor resonate with each other, exchanging energy back and forth. The frequency they resonate at is the radio station's frequency. See my "How a Crystal Radio Works" video for more.
I made a crystal radio from a kit when i was in the cub scouts at about age 10. It worked!
Richard Turner know how to make a potato radio that actually works?
It more fun to build stuff out of crap
Wow ! Relived my childhood. Mine was a simpler one. I used to detach the earpiece of our chunky old telephone. Attach the two ends of a galena crystal to the two electrodes of the earpiece. connect the earth and aerial to each of those electrodes and enjoy the strongest available medium wave. The ground rule was, got to replace the ear piece before Dad gets home
Cool! That's definitely about as simple as you can get.
What great memories...I did hours of listening on just a diode and earphone. And on tuned sets I DXed other states at night and even shortwave broadcasts.
Jumpstart Jimbo: Have you uploaded the video about this method? I have a faint memory my elder brother did it in the way you mentioned. We used to listen to the local radio station so clearly. That was 70 years back when I was a small kid. I saw the crystal (so he said, there was no diode or any other thing except the telephone receiver which he bought from the Calcutta second hand market) and with a slider (that is the wiper) we can tune in the radio station. Will you please do a video about this method. I believe many like me will be interested about it and they will be benefitted . Please do it and upload the video if possible. I want tp make like this in memory of my elder brother who is no more in this world. He had curiosity things like this.
This truly is great. The tunable capacitor from foil ! Amazing, high quality video.
Especially as air-variable caps are getting more and more expensive.
I never thought to look in an old smoke alarm. Thanks! They definitely sound like peizo buzzers.
And yes, this coil and capacitor are for tuning in 540kHz to 1.6MHz. I'm away from my own computer this week otherwise I could easily calculate what's needed for 198kHz but I'm pretty sure you need more turns.
Damn I knew this was a old video the second he said Radio Shack
I've been looking for a simple crystal radio for my young grandson to build. This looks like the perfect project! Thanks!
Cool! Be sure to check out the playlist. ruclips.net/p/PLFsZmHTZL-zlSltC6ELZW9PK4ks7wgPRz I made a bunch of related videos on the topic, including troubleshooting and tips and how-it-works.
I've watch several already. You do a great job!
Great Vid, short and too the point!!! I made one when I was a kid, my dad knew eletronics, and tried to teach me, at the time my dad had a heath kit 2 m reciever that was soo cool!!
I still dont know much about elertonics, and was wondering ???...
If you could use a modern day germanium diode, I bought a kit from china for my raspberry pi's to start learning stuff, and it has a lot of germanium diode's... but not 1n34....
If they're germanium diodes then they should work. Are you sure they're germanium diodes though. Most diodes that you see these days are silicon diodes and those require a more power signal from the radio waves, usually meaning an antenna a hundred or more feet or being very close to the radio station so that you get a strong signal..
@@RimstarOrg Thanks for the info, I am not sure of anything!!... ha ha ha.... all I know for sure is the diodes I have look like the one you showed in the video.... but smaller
Thank you. This is brilliant. I am researching for a novel set in a WW2 prisoner of war camp, where I've been told they had a crystal radio, built with smuggled parts. I couldn't quite understand how they could have built it, but now I can see the simplicity of it. This has given me everything I need to know! I also really liked your snappy delivery and the way you had filmed the video. Thank you.
Indeed they did and more: look up Roy Kilminster's site, he was a prisoner in Stalag Luft I and they had a radio built with smuggled tubes. He was the keeper of the radio and has pictures of it and how they hid it in a wall.
I search this after i read a japanese manga call dr. Stone
Can you make a crystal SW radio?
Yes, just make a shorter coil
weirdest meth lab ever
Different strokes for different folks at 1:15 ;D
I am 73 and have two crystal radios one I made with a razor blade as the tuner in stead of the wiper . I can get three station one is 35 miles away wwva large powered station
That's pretty good for a razor blade one. I know I had trouble getting anything with mine. How long is your antenna?
Over 250 ft I am also on the highest point in my county
george330ful
Wow. 250ft is great, I'm envious. Sounds like a great location.
Yeah, remember that trick. Glue a razor blade flat on a wooden board, fix the head of a safety pin near it with a nail, touch the sharp point of the pin vertically on the flat surface of the blade. That'll work as a crude diode
Jumpstart Jimbo I believe they used to call that a cats whisker
I don't know of any way to do it using a transformer, not that that means there isn't one, but I've made two amplifiers by other ways. One amplifies it for the earpiece and the other amplifies it so you can listen using a loudspeaker. See my "How to Make Amplifier for Crystal Radio Earphone" and "How to Make Crystal Radio Amplifier for Speaker" videos. There are links to them in the description below this video.
I don't know if you will manage to make them. If you have 6 months and you start right away, then I don't see why not. Depending on how old you are and how much experience you have building things then you might need a little help from your parents or teacher but 6 months is a long time if you don't wait until the last minute. The cost should be less than $50 US approximately. Feel free to ask questions here too.
Those were the days of learning about radios and how they work and how to build them. So many youngsters of todays generation could learn so much from videos like this, but many won't be interested because of computer rubbish. Thank you for this video.
i like computers and learning how things work dont count me out on wanting to learn about this kind of stuff its very interesting
@@freeze0895That's wonderful! Pity there aren't many like you 😊😊
@@mikebledig7208 yeah I agree all of technology is so interesting pcs radios n64s game boys (game boy colors!) there’s so much yet not enough time
i'm a brazilian younger and learning using a computer...
can we use silicon diode and less no of turns plz cmnt
Typically, no, a silicon diode won't work. For that you either need a very long, straight antenna (over 100 feet) or to be next to a powerful radio station. And yes, you can use less turns. You just may have more overlapping stations since you're compressing them into a smaller length of coil for tuning purposes.
Thank you for valuable reply
RimstarOrg could you tell me any other alternatives of capacitor (trimmer capacitor)
I show another DIY design in my crystal radio tips and tricks video ruclips.net/video/HZZmKZJrIW0/видео.html. I have some links to where you can buy on in the video description.
Sir I'm working on this project and I have two questions
1. can we have any other option for grounding because it may be dangerous and I want to make it portable.
2. Can we use one earphones piece for sound will it be much sensitive to sound.
Sir plz help its my project
1:15 = money shot 🐲
:'D :'D :'D Oh god. :3
SB please tell me, what is this? How do you use this? What is it for? Where is the crystal in it because I missed that. Thank you.
There is no crystal. In the original crystal radios from the early 1900s they did use a crystal instead of the modern diode and that's where they got the name crystal radio. But these days a crystal radio is any radio that gets its power from the incoming radio waves.
8:57 25 turn coil and 90 turn coil ?
I'm actually working on a video explaining how many turns now, but it won't be out for a week or so. The capacitor and coil form an LC resonant circuit. It doesn't have to do with wavelength the way you seem to be thinking about it though. In the meantime, I have some calculators here rimstar.org/science_electronics_projects/lc_circuit_aka_tank_or_resonant_circuit.htm for working out the right coil. I also talk explain it in my How a Crystal Radio Works video ruclips.net/video/0-PParSmwtE/видео.html.
Did you mean FM transmitter and receiver? rf means Radio Frequency which is from 3kHz to 300GHz. Both AM and FM transmit using frequencies in that radio frequency range. A crystal radio is an AM receiver and I already have a video "How to Make AM Radio Transmitter" (see the link in the description below this video.) FM transmitter and receiver are both high on my todo list but I don't know when I'll get to them. It's a long list.
The only difference between a foxhole radio and an old style crystal radio is that the old style crystal radio used a galena rock crystal and a sharp wire for the diode and a foxhole radio used a razor blade and pencil for the diode. My video "Make Razor Blade Diode for Crystal Radio/Foxhole Radio" is a foxhole radio because it uses a razor blade and pencil. There's a link to it in the description below this video.
You can burn the insulation off with a lighter
Yeah i too did that on the ends of each wire. However i would not recommend doing that instead of sanding off the coating layer for the wiper. You only wanna wear off the upper layer, not the whole coating all around the coil on that spot.
u can burn the whole radio with a lighter
This video is a big motivation and knowledge source. Thank you so much for that. I am teaching a lab course and including this as the final project. So I had tried to make it as simple as possible and actually providing kits for every student. In the process, I have gathered the following thoughts:
1) Coil: I find the sliding option a bit challenging and intimidating, although I did get it to work. My modified design is a total of 65 turns, with a small loop at 40th turn. So there are 2 settings, 65 turns with the loop not touched, and 40 turns with the loop grounded. Between these 2 settings, the frequency range is quite good. After all, you just want to get some channels to show off, but not necessarily all the channels.
2) Capacitor: I tried to “improve” your design, but finally realized how good yours is. Thought of parallel plates that some people use, but bowing near enter is unavoidable, while your tube design has no such problem. I also tried other materials to make it more rigid than aluminum foil. I tried flashing materials (aluminum and galvanized steel) but they are too stiff and leave too much gap between the inner and outer tubes, so probably loosing some capacitance for the same size. I wound up using thicker aluminum foil available. I was also concerned about the contact by taping, but convinced myself that contact to capacitors is not that critical, since there is no DC current.
3) Speaker: This is more critical and difficult than I expected. Piezo earphone did not work for me, and it was a bit expensive ($7) and I returned it. Piezo buzzer (much cheaper) I could hear something but is quite faint, so hard to tune channels. I also tried piezo transducer, and it did not work. The best I used was a guitar amp, but not everybody has one. Next I will try are PC speaker and headphone (both suggested by your viewers).
4) Wish I could show a photo of my final project, but I did not see that option.
Again thanks a million. It’s nice to see old school is kept and being pursued. I am retired and always wanted to do it. Well I finally did!
Thanks for sharing all that. I've had the same problem when teaching a class, having to find the cheapest and simplest way that works. So I can relate. I'm glad to hear it worked out.
I want to make one but I don't think I have the patience. 😂
Thanks. You can buy crystal earpieces online. See the description below this video for links. You can use piezo buzzers that you buy at electronics stores like Radio Shack. You can use disk piezo crystals taken from various things. See my "Make Crystal Earphone/Earpiece for Crystal Radio" video for taking one from a microwave oven. You can use normal earbuds. See my "Use Earbuds/Earphones with Crystal Radio" video for that. Links to the videos are in the description below this video.
No, the crystal radio can't receive FM. And you're right, if the nearest radio station is 100km away then the portable crystal radio won't work, at least I doubt it will. You can make your own AM transmitter. I show how in my recent video "How to Make Crystal Radio Amplifier for Speaker". There's a link to it in the description below this video. Just make sure your transmitter can't transmit very far so that you don't interfere with other radio stations.
How long is your antenna? 1N4148 is a silicon diode. That and the zener and avalanche diodes need more voltage to start conducting than mine with my three parallel 15 foot antennas. I'm guess either you're antenna is pretty long or you're near some powerful radio stations. Let me know so I'll know if I should add them to the list in the description below this video with a caveat.
1N4148 is a silicon diode. You need a germanium diode. I haven't tried it myself, but someone here reported it works if you use 5 silicon diodes in parallel, meaning connect all their striped sides together and all their non-striped sides together. You can't use normal speakers. You can use normal earbuds (like iPod earbuds for example) using the trick in my "Use Earbuds/Earphones with Crystal Radio" video. There's a link to it in the description below this video or see my channel page.
No, a crystal radio doesn't require batteries. It gets its power from the incoming radio waves themselves. That's what makes these so fun to work with. But it also means that unless you have a very long antenna and a good ground connection or a radio station nearby, then you'll either have trouble getting something or it will be very quiet. Plus, you'll usually need earphones to listen to it, not a speaker. Or you could add an amplifier circuit, but that's no longer a crystal radio :).
Two diodes in parallel in the same direction, side-by-side would help. A full wave rectifier wouldn't work.
Do you mean as when you put the "phone on speaker" so everyone in the room can hear it? If so, you'll likely need an amplifier circuit. If you mean a piezo speaker in the listening end of a phone then just extract the crystal and use it as in the video. If an electromagnet type speaker then you might be able to use the trick I use in my "Use Earbuds/Earphones with Crystal Radio" video.
I'm glad to hear it worked. Are you sure you have a germanium diode? One reason a germanium diode is important for the particular crystal radio circuit is that germanium diodes are a bit leaky, which is needed for reasons explained in my How a Crystal Radio Works video. I suspect either you have a germanium diode and some current is leaking through the high resistance of your body, helping with the leakage, or you've a silicon diode and your body is providing the needed leakage. Just a guess.
A Schottky diode wouldn't normally work with this circuit. However, I haven't tried it myself but it's been reported below that 5 silicon diodes wired in parallel worked, possibly doing the same with Schottky diodes would work. I wouldn't guarantee it though. Parallel means all the ends with the stripes connected together and all the ends without the strips connected together and use where the diode normally goes.
One end of the antenna wire isn't connected to anything. The other end goes to the end of the 25 turn coil that is farthest from the 90 turn coil. See the diagram in the video at 0:24. Since it's the ground wire you're connecting to, you shouldn't have to switch on the extension box (I don't have an extension box to switch on anyway.) See my video "Crystal Radio Troubleshooting and Tips" for more about grounding. There's a link in the description below this video and on my channel page.
What is the diameter of your ferrite core? For one that's around 1cm in diameter you need only around 30 turns instead of the 90 ACCORDING TO MY CALCULATIONS. I haven't tried a ferrite core myself so I suggest more turns anyway to be safe. Having extra turns doesn't hurt if you have a tuning bar since everything after the tuning bar doesn't count. You might be able to use two coils if the ferrite and the coils are touching. How long is your antenna and what are you using for ground.
I just lay a long length of wire across my floor. Mine isn't very long, only around 3 meters, but I pick up a few nearby radio stations and a few that are a few hundred kilometers away. Most of the time I actually lay out three wires parallel to each other and connect them together at the radio. The diameter of wire (wire gauge) doesn't matter much. Longer is better. And if you have one radio station you always listen to, point the wire at that station if possible.
If you're getting fluctuating pitches and crackles with no external power source than the radio waves, then I suspect you're getting something, even if it's just a jumble of electromagnetic waves. I suspect you may need a better ground too. A butter knife in the ground doesn't give much good electrical contact. You could pour water over that spot to dampen the ground or bury a larger object. Normally a 6 foot rod is used. Google search "ground rod". But try your antenna first.
Ah, a few problems then. An 8 feet antenna isn't very long, unless you have radio stations nearby. I do and with my three parallel 15 foot antennas, the stations come in fairly quiet. Good innovation with your ground, hopefully it's enough in the ground. The wetter the ground the better. But I just checked 1n4148 and it's a silicon diode. With your short antenna, I'm doubting you'd get the voltage needed for the diode to conduct. Maybe try two or three in parallel or find a germanium diode.
I got mine on ebay. Germanium diodes are best. Other germanium diodes are 1N60, 1N91, 1N119, 1N270, 1N277, 1N283. You can also try two or three silicon diodes in parallel (all the striped end connected together and all the non-striped ends connected together.) I also recently uploaded a video showing how to use a razor blade and a pencil to make a diode but it didn't work great (see video link in the description below this video.) And it doesn't have to be magnet wire but it must be insulated.
A 3v piezo buzzer should work. Mine is 4v minimum, so yours requires even less voltage than mine. I'm assuming your buzzer comes in a black case with a hole in one side. Cut a plastic tube, like a pen, around 1 cm (1/2 inch) long and glue it over the hole, then you can better direct the sound into your ear. I find they're not as good as the commercial crystal earpieces, but they work. Maybe your problem is elsewhere? Check all connections. The longer the antenna the better. Us a good ground.
No, if doesn't matter what part the positive and negative terminals are connected. It doesn't matter which side of the capacitor is grounded as long as the circuit remains the same i.e. don't ground the diode. Touching it doesn't provide a good enough ground, although someone below said they had luck that way by wrapping aluminum foil around their finger and then connecting to the foil for ground, thereby contacting more skin surface area. How long is you antenna? The longer the better.
The configurations I know of are stretched out straight pointing at the radio station (if you know where it is) with the crystal radio at one end or with the crystal radio in the middle. Either that of coiled up in a large coil around 2 feet in diameter, with around 15 turns, with the crystal radio connected at one end and with the open end of the coil facing the radio station. For an example of coiled approach see my "Portable Crystal Radio using Loop Antenna and Pizza Box" video.
If you use a metal rod then that changes things a lot. What is the material of the rod? What is the diameter of the rod? Some quick, rough calculations for a steel or iron rod that's 1cm in diameter shows it needs only 30 turns and will be only 1.4 cm long. Your second question is kind of hard to answer since the meaning of reception is vague. One way to get less static is to increase the distance between the two coils but the volume will be less.
The 50km distance could be your problem. If the antenna is a coil like my pizza box portable crystal radio then it's not very powerful. You could try putting you hand on the aluminum foil of the capacitors, making sure to get lots of surface contact. Try it with the outer foil cylinder and then try it separately with the inner foil cylinder. Your hand will act as a ground.
Do you have any radio stations nearby? If yes, try pointing the antenna at them. How long is you antenna? The longer it is the better it'll work. Mine is 15 feet long, with three in parallel and I get only the nearby stations. The antenna should be stretched out in a straight line as much as possible. Do you have a good ground?
I don't know. They look identical to me based on the photos. I bought mine from midnightscience years ago at the same time I bought a bunch of books and one of their radios. They worked great until I broke them, but that was my doing (I opened one up out of curiosity and the other one I cracked by accident.)
I've no experience in sw so I can't give a good answer. I have tuned in 1.8MHz with the radio in this video though, but that still leaves a lot of sw. What you say about using a grounded stiff wire that moves over the coil so you can hear mw sounds right, and in fact isn't needed since the tuning bar in this radio is just that - it's grounded.
No, there isn't enough power to run the coils of an ordinary speaker. Well, unless you have a really long antenna. It's not the best but you can use ordinary earbuds if you add a small transformer. I explain how in my video "Use Earbuds/Earphones with Crystal". There's a link to it in the description below this video and you can find it on my channel page.
Much literature; especially the older pubs suggest using water pipes as a ground. That only works in older homes/buildings where iron pipe was used in the water supply. For many years, PVC has replaced metal pipe in home plumbing, and PVC is an insulator. The only thing in the house that will function as a ground is the ground terminal of an electric plug --- as you have done. Still, I'm afraid to recommend that given the number of people who don't know ground from hot and neutral. :(. I recommend driving a metal pipe a few feet into the ground for ground use.
You could also try a razor blade and pencil diode. I found it very hard to get working but it's another option. See my recent video "Make Razor Blade Diode for Crystal Radio/Foxhole Radio". There's a link to it in the description below this video and on my channel page.
Yes, the other end needs to be grounded. Without it being grounded it won't work as well. The ground provides an easy path for the electrons to take. See my video "How a Crystal Radio Works" at 0:40. There's a link to it in the description below this video or you can find it on my channel page.
Yes, but you'll have to add a transformer. To see the details watch my video "Use Earbuds/Earphones with Crystal Radio". There's a link to it in the description below this video and you can find it on my channel page. (I seem to have a video for everything :)).
If you're talking about the aluminum foil, it doesn't matter which side is up. The only difference between the shiny side of aluminum foil and the dull side is that one is shiny as a side effect of how it's made. There's no coating on either side.
The voltage difference comes from the incoming radio waves. The radio waves themselves are your power source. No battery is needed, unless you want to increase the volume by adding an amplifier. See my video "How a Crystal Radio Works" for more on this.
I don't have any way of measuring the inductance. The best I can do is calculate it and it ranges from 0 to 0.369 millihenries. I measure the capacitance in my "Crystal Radio Troubleshooting and Tips" video and it ranges from 0 to 640 picofarads.
The antenna doesn't need to be hung. I use 3 15 foot wires connected in parallel and run across my floor. Though if your floor is metal then there may be a problem. The higher up you go in the air the better, but mine works fine on my hardwood floor.
One way is to make a radio transmitter and transmit music to it. You can see me do it in my video "How to Make AM Radio Transmitter". There's a link to it in the description below this video.