How to Make a Foxhole Radio
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- Опубликовано: 29 июн 2024
- I had to make a video project for college showing how to make something and one of the videos i watched a few days before getting the project was this • How to Make a Foxhole ... so I decided to make a radio!
PDF: cdn.makezine.com/make/wp_foxho... 
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These old videos are genuinely GOLD. No bullshit, unnecessary music, horrible intros nothing. Legendary
Thanks, Shane, I've been making crystal radios and tinkering with electronics, repairing many small devices just because I want to do that, all for 55 years. Where is jack for amp connected to the board? At Razor blade and pencil? Besides razor blade, you can use rusty nail/corroded penny and SHARP safety pin. For advanced guys, use a flame--alcohol(?) on razor blue stainless blade and sharp pin but not touching, only close, very close to each other. You can make a tuner across the coil top, drag across top of coil with sharp tool or knife to remove some insulation just on top of coil wire but not touching one wire to another or the coil will be grounded, option when winding coil is to twist the wire every 10 windings and remove some insulation of each tap, remove one side of coil wire and drag across top of coil or touch each tap to tune local stations. I use a lot of alligator and Fahnestock clips. A stronger tube will be necessary for strength, PVC pipe or similar shape for the coil and a coating of glue will make it permanent. A good earphone is from the old style carbon ear phone from dial telephones as most are obsolete. At 70 yrs old, I have a lot of junk parts from phones and variable tuning capacitors, V-Caps, from old radios, if unknown capacitance, just try them, will tune a crystal set and either with or without the coil. One night without the coil, no tuner, using powered speakers, I picked up Radio Havana on 6.0 MHz and some religious stations just under 6.0 MHz, no tuner, 30 ft antenna wire out the window or on the wall up high and ground was a long nail into the dirt outside the window, ground wire to the radio. Another antenna and ground can be had with old wire bed springs found in old Army cots, one for antenna and another for ground. Antenna and ground with air between them is a capacitor, same with antenna wire and ground picking up lightning, AC and RF radio signals, AM radio, even SW and CB radio, all kinds of fun.
Bill McGraw, KF5FJZ, NRA Life
"Somewhere South of Chicago"
Greenville, Mississippi
General license for only 3 years as a ham, 70 yrs old fart
All these devices replace what was once called a cats whisker, small bit of crystal held in a holder with a fine wire used to find the sweet spot where you would get a signal.
@@jimnoyb1209 I used a safety pin with a nail into a piece of wood for a base, a piece of lead wired to the point of the pin. You then moved it about the razor blade till you found the spot. A tuning capacitor enabled it to be tuned, received two or three stations. This was about 1962 or so.
Good question! The power source is the radio wave themselves. That's why you need so many turns on the coil.
Must have been a Spanish pencil !
lol
OMG!!!
The softest lead is the best, it is almost pure graphite, no clay particles
I sense someones gonna get wooshed
@@koppo5657 yup, that's me...
I don't get it
So happy I found this , I heard of this 40 years ago , but I couldn't find prove .
Congratulations 💐💐 Shane
Completed.. 1k subscribers ....
I found your video the best so far in demonstrating the assembly of a fox-hole radio. You'd make a good teacher or scientist. Very methodically presented.
I knew an old Ham, K4IVK, who built one. He gathered all of his needed components from "out in the wild", roadside and other areas. Except for the crystal. He was a genius. I remember the Quaker Oats box... Rest In Peace, Vic.
thank you for a very good video!! this is the best one I have seen on you tube thus far but may I make just a small suggestion some house wiring in many old homes can be bad or faulty it would be much safer to stay away from that type of a grounding system. just ground it off on a copper pipe in your house,or just buy a cheap grounding rod. again this is a great video on how to make a foxhole radio, and we "appreciate" all your help, but we want all the little ones and us big ones to be safe.
Wonderful video! Better than any other! I thank you for all this help! (This is my project for the science exhibition)
I used to have a R/C car as a kid that I dropped once and after that I could get a radio station with it. As a kid I was blown away, now I'm 41 and I finally understand why it happened....still cool to me though. Great vid!!
Good job!-Am amazed that it worked at all with tape instead of solder! Bravo!:)-John in Texas
yeah,you really can't have bad contacts or resistance here,won't work...
Pretty awesome. Ive always meant to learn how to make those at home, never got around to doing it.
From what I understand the radio waves send electricity back and forth through the coil. So the more turns you have the more power/signal strength you will get.
The razor and pencil "lead" is a semi-conductor, current flowing only in one direction, not sure of polarity from antenna or ground. If it doesn't work, reverse the polarity, might be wrong but I try a lot of combinations.
Great video. I think I'm going to give it a try! Thanks for sharing.
That's pretty cool! I tried this 20 years ago when I was in elementary school with no success because I missed the step of heating up the razor blade. I like how you hooked the radio up to the amplifier! I'm going to have to give this another try!
in the old days you didn't need to heat the blade, trick was you needed a Gillette Blue blade,
I wish I would have known that all those years ago. I got the plans out of a book from the library and they left that vital tidbit of info out. lol
It's the junction between the graphite pencil lead and a tarnished section of the razor blade which forms the diode, which is why the razor blade is heated first. It accelerates the tarnishing process. You have to hunt around on the blade with the pencil lead in order to find the right amount of tarnish to form a diode.
You can also soak the blade in salt water to oxidize it
This is cool as hell! Gonna make one myself just for kicks. I'll make sure to give you credit when people ask me how I learned it, cause I'm gonna show everyone I know lol! Thanks
Pretty cool! Great job here.
Nicely done, thanks for sharing!
Kudos on the winding of the wire, very nice work.
I failed at my first attempt (I was a bit short on copper wire for the coil) but I'll try again. Thanks. At least I can say that I know how to make a radio now!
30 to 40 feet of 24 to 30 gauge enamel or plastic coated solid copper wire should do it
To add what I stated earlier, a semi-conductor can be had in a flame, alcohol, propane, with a stainless double edged razor blade by itself or heated in propane flame until it turns shades of blue, corrosion oxidized, and another dissembler metal, copper, slightly apart in a grain alcohol flame. The rusty nail and corroded penny work well, just difficult fining a hot spot with the sharpened safety pin. Try a piece of hard carbon/graphite and a pin instead of "modern pencil lead, " now a clay mixture, carbon/graphite might work on the razor blade. Two metals, copper/steel close together with a drop of vinegar in between the two metals may work but as a low voltage/amperage battery, it may or may not work. Think semi-conductor as in power signal from the antenna is changed from AC, the RF signal, into DC current to run the earphone.Then find or make a tuner.
The pencil and razor blade are creating a point contact diode.
thank you. eggscllent presentation. clear and concise. no text to speach or graphics that i cant read.
Apparently the layer of oxide that forms (which gives it the blue tint) is needed.
WoW it works great job. 1/24/2022
Nice job on the coil.
Fascinating and thanks very much .
I believe the length of the antenna actually has more to do with signal strength than the coil does. The coil has more to do with tuning, as I understand it.
I don't know so much about the razor blade (and tuning with it), but if you swap it for a 1n34 Germanium diode (properly biased) you would use the coil for tuning. That's how it was with my brother's crystal radio when we were kids. I hope it helps.
Yes, the coil determines the frequency.
A longer antenna should give more volume. The best way to tune is to add a variable capacitor connected from the ground to the antenna. However, this wouldn't be true to the original foxhole radio. You could also make fixed salt water capacitors across the coil. Different values for each station
Way cool. I like how you used the Amp also. What if we substitute parts, like a bigger piece if metal, wire, and caps or diodes??
A razor blade would be your best bet for it to work. You can try to use a piece of metal just make sure its stainless steel its thin and your heat it up like I did the razor blade. Good Luck!
We used a carbon rod, rescued and cleaned up, from a depleted zinc carbon battery cell and it was fastened down to the bread- board for stability. The razor blade was fixed across the carbon rod with springiness of the blade and it was moved to find a sweetspot as a detector. When a good spot was found, it could be left there to keep working whilst you sat and listened.
Our razor blade was not heat treated. Looks like we were missing something there?
A .001µF fixed capacitor, connected from the pencil paper clip to ground would have increased
the received sound BUT without a tuning capacitor, stations can't be selected (tuned).
That would connect from the razor blade paper clip, again to ground.
I reckon unless you are extremely close to an AM transmitter, 15 feet of antenna would probably not get enough signal to work on.
Imagine if you were under-fire in a fox hole, with crap and bullets flying overhead, trying to hold the antenna high enough with one hand and hold the pencil still with the other and then trying to dance to the Mexican Music.
Great project..Good ideas on constructing it but lacking in vital info to make it practical.
120 turns would take you towards the bottom of the medium wave band, getting into the long wave section of the AM band. I'd be inclined to experiment with 80ish turns and a tuning capacitor of 0.005µF which would move you further up in to the Medium Wave section where I reckon there might be more stations operating.
that is a really neat video
cool build dude
I continue to look at the various ways of making radios. This on is unique since I've not seen the paperclips used so, nor heard the exact number of winds (120),.
I usually use 30 to 50 feet of 30 gauge wire for the MW (AM) band
Great video, I really like the simplicity of your radio, however I've never heard of this style radio called a foxhole radio. Typically they're called crystal radio's.
I've made vhf/uhf and cb foxhole antennas for extreme directional control for specific long range uses.
This type of radio was built by our troops during ww2 to receive allied and German radio stations, a powered radio was rightly or wrongly thought to give off rf which enemy forces might be able to home in on. Used in foxholes, thus foxhole radio.
that is fabulous!!!!!
I really appreciate that! Thank you. :)
you can burn the coating off the magnet wire its easy and quick
Cool man I actually looked this up. I saw it on Mail Call.
i would guess that it has something to do with capacitance since now you have a conductor and non conductor layer... if i remember right, the crystal radio i made had a capacitor in it... the other thing was the germanium diode... it may be it's replacement ... . making it necessary for the curren to travel in one direction only and not oscillate in the wire?
Try moving the radio to another end of your house. Or try to adjust the antenna to get a signal. Be sure the coil is wrapped tight so the wire will not cross over on its self. Other than that I wouldn't know what to tell you. I was surprised mine worked on the first go. Good Luck!
Hmm.. Old trick but having found a sweet-spot for a signal, must the operator hold the pencil until the radio programme has finished?
Its a crystal radio where the graphite pencil lead acts as a diode and the razor blade acts as a tuning cap.
No, there's no tuning. The junction between the graphite pencil lead and a tarnished section of the razor blade acts as the diode, not just the pencil lead on its own.
Instead of an oxidated razor blade, a tarnished penny works too.
Yes. I've done that
It's about 45mm. It doesn't need to be exact or anything, its just if the coil was to small (say 15-20mm) I don't think you would get a very good signal from it. But I have never tried it so I could be wrong
Cool thanks. Good explanation.
If you keep the razer aimed upward it will catch the radio waves better.
Sorry I am replying so late. Im not sure if that would work. The power is generated from that coil so if it was to small I don't think there would be enough for it to work.
Thank You ! I love it ,cool ...
Muchas Gracias! Very useful and succesful
Do we have to switch the plug on on which placed the ground wire
Which wires do i connect an audio jack too doe's one wire + for e.g go to the pencil and - go to ground ?
NICE MAN IT WAS GOOD
See how he has connected the ground and pencil wires, each to the two wires inside the audio jack? Instead of connecting them to the two wires in the audio jack, connect them to the two wires in a head phone cable (which will involve cutting it open). To save the headphones, simply wrapping each wire around one piece of the headphone's plug (it should consist of 3 metal parts separated by a plastic barrier, connect a wire to the tip and ring).
What was the thickness of wires you used for the coil?
What A Great Video :) LOVE IT !
What device did you plug in the radio that you designed into the device, but I did it, and the two ends of my coil made two antennas one wire connected to the 10 m long clothesline and one string to the ground. and I don't see any rustle in the headset. Can you explain and help me and guide me.
Thanks Friend.Gotta Check it out.
Bro,i am building a foxhole radio following your example,however,it is unclear how to connect the wires to the pencil and amp.....is there two wires connected to the input wire plugged into your amp,and if so,where does the other one go(besides the one connected to the pencil? Please clarify for dummies like me......thanks,jonboy wilson,cullman,alabama....
The razor Blade just has to be heated once, right? Like, if I heat it once and then use it a week later it wud still work a week later, right?
Yes sure, the heating is just to oxidize the surface of the metal.
long as it don't get rusty, you can get an old blue blade off the web from some of the shaving groups. In fact I have one sitting here on the desk.
Hi, is the other end of the antenna open ended? I used copper wire instead but it didn’t work
WHAT ABOUT THE COIL ? I THOUGHT YOU SCRAPED THE TOP OF THE COIL WITH A METAL PRONG TO FIND THE STATIONS
mw10259 not with foxhole radios
Well done shane, Tip. Heat the razor blade up red hot and let it cool. Use the blued portion as the detector.
Your ground system looks dangerous. If it touches an active pin you will be in trouble.
"IF" is a magic word....
@@julikb Shit happens...
or you can put it to a water pipe
Unfortunately,most rooms don't have copper pipes in them. And newer homes have plastic pipe. A metal pipe or rod about 4 feet long driven into the ground outside ofa window works very well.
Another safe alternative is a counterpoint wire around the baseboards of the room to use instead of a regular ground
One time I used a small garden spade stuck into the ground. It worked OK.
Best vídeo! 👍
how to connect speaker
how about details re adjustments on the coiled wire?
Hello.. I make this radio.. My ground connection and antenna are very good and I collected the wires very good but it's not working... Are all razor blades can work? ..Or any other heating degrees .. I just cant understand why it's not working .. i can't get buzz even ..
it receive AM or FM? I hope you can help me.
I put a link in the description of the video.
What is the reason behind heating up the razor blade? And would a utility knife blade work also?
To oxidize it. You could also soak it in salt water
Great!!
Very cool! What is the purpose of heat-treating the razor blade, AND would it work if the tuner were just a paper clip scraping on the blade without the pencil?
Heating takes off factory applied lacquer so the graphite in the pencil makes good contact directly to the steel. Moving the pencil acts like a variable resistor like the dial on an analog stereo, so if you used a paperclip there would be no resistance and therefore no tuning.
NOOOO. The razor blade with the graphite pencil forms a diode to clip off one half of the AM wave.
The heating forms a super thin oxide layer on the razor blade that together with the graphite (you could also use metal, but it would damage the oxide layer more easily) forms a metal-semiconductor PN junction with the oxide layer being the semiconductor.
i think i can 3d print all of this... hold my beer plz.
using a razeer blade for tuning is quite fidigty.
I don't think they had wall plugs in the foxhole man so how would you do it without a wall plug would you just use a river 9 volt battery or any kind of battery you had and then use some cheap headphones that they would give you
This is amazing !
Though I have a question ?
Could you type the supplies on here please ? It would be nice x
u would need
-toilet paper tube
-magnet wire (normal wire with a non-conductive coating)
-tape
-paperclips
-thumb tags
-rusty or blued razor blade
-broken off pencil head
-regular wire
-cardboard or any wooden board to put it all on
BUILT ONE YESTERDAY AND PICKED UP JACK BENNY
@AndGoProductions I really like your video and pls reply. i have all the necessary components but is there asnything i could use instead of a razor blade? Like can i use a piece of metal?(i dont know much about this kind of stuff but im only a kid)
Many kinds of oxidized steel or copper might work. I used a pocket knife blade one time. An old penny might work
You know for the ground you can just wrap wire around the sink taps
I have been trying this all day and cannot get it to work all i get is static. I have sent it a signal through another coil and its picking it up but so the coil is working 😯.
Probably need a longer antenna or a ground
An excellent video. If you're using a copper pipe as a ground, a cold water pipe eventually goes into the ground. A hot water pipe in a tankless system may be ok, but a pipe that goes to a hot water tank may not be grounded. In Canada, in most cases, there's a grounding clamp on the cold water pipe just after the water meter, which is just after it comes into the house. That's the best ground I can think of besides a 6 foot copper bar in the ground.
Somewhere in the collection of wobbly floobydust that the site uses, there no doubt is a part that will be very surprised by my comment. It may react by suggesting others watch.
how do you change channel. i dont understand bbc wales
np!
can i use some thing small insted of a toilet paper tube...? like a pen or marker...? Thanks a lot.
It's better to use something larger I wouldn't much smaller than a toilet paper tube. Maybe an inch in diameter. The smaller you go, the more turns you'll need to make.
However, anything cardboard, wood, or plastic would work.
Is there any substitute for the wire u used to make the antenna and grounding.. i dont think we get it where i live.. and will any earphone work..or is da piezoelectric headphone necessary
ANSWER ASAP
A magnetic headphones over 1000 ohms will work. And they will last decades longer than most piezo earphones. The newer pink earphones go bad in a few weeks or few days. You have to tap them on the table every 2 minutes to get them to work. The new ones have the contacts glued instead of soldered.
I have a set of headphones that just turned a century old this year
How do I wire the audio output wire to headphones / earbuds?
One end on the detector opposite theend that goes to the antenna. The other end to the ground.
If you're using a magnetic headphone, it has to be more than 1000 ohms. Most newer headphones are 8 to 32 ohms.
excuse me I have problems to make it. stainless steel razor blade it has not being problem?
hmm this razor it is diode or capacitor??
It's a diode
Why do you heat the razor blade?
excuse me, Not regular wire, another wire is it there relations about 'mm'?
i dont have a razor blade but can i use a flat piece of iron or tin foil?
It might work with iron, but it's less likely to work with tin (actually aluminium) foil. What creates the diode is the junction between the pencil lead (graphite) and a tarnished section of the metal. Heating the metal is used to accelerate the formation of tarnish (iron oxide usually).
In short, it might work with any metal which oxidises but all you can do is try it and see.
how to change the wave
Is it SW Radio?
why razor blade is heated?
There is no tuning capacitor. The pencil takes the place or a germanium diode, not the tuning cap.
nice.
What if you don't have an amp?
An old headphone that is 1000 ohms or greater will works