How to Make a Foxhole Radio
ฝัง
- เผยแพร่เมื่อ 26 ก.ย. 2024
- During World War II, GIs in the field built really amazing simple radios to listen too. These were made with materials that they could get their hands on and were small enough to carry around in a big pocket. You can modify this design if you want to set it up so that it's tuneable too! To see all the plans, go to makezine dot com slash podcast!
Find more at the Maker Shed: makershed.com
Make: Electronics, 3rd Edition: www.makershed....
Learn more here:
cdn.makezine.c...
Heating the razor blade creates a dioxide layer on the blade (2 materials) which turns the razor to a detector (diode). I think kind of that layer is also being used at the gate of mosfet transistors.
We did it with my friend when I was 12 years old. Although we cannot get sound from the radio, I am an Electronic engineer candidate right now :)
I bet you could get one to work now.
i made one when i was 8. It is not a big deal.
@@25_26 congrats mate im happy for you
How did it go? Your uni I mean
Just a candidate? Not even an engineer?
This was the very first TH-cam video I ever watched, oh the memory's
Hahahahaha
I watched Me at the zoo. Gives me the willys to know what you watched. Its so interesting. Im going to like this comment and have my followers all like it too so you get money from TH-cam.
@@UpcomingJedi what lol
I actually had to check the upload date. The production value is so high!
Did you watch it while you had the movie “Hart’s War” on pause…. Like I do now? 😂😂
Props for showing the entire learning curve, failures and all. It helps us understand the diagnosis process better. Thanks.
The problem you had with the Razor blade was the rust resistant coating that comes on modern metal to make it last longer. you can burn it off or scratch off the coating with sand paper
jesus i watched this video in 2007 once..... remembered it.... and found it again 14 years later
What does JESUS have to do with this?
@@sallycarroll6329a lot of
@@sallycarroll6329wow you're truly a very intelligent individual
@@sallycarroll6329 Alright Sally, time for arts and crafts...
This video is over 9 years old, becoming a great classic crystal set project video.
13 now 😂
@@dixiegracebrown SIXTEEN NOW 💯🔥
@@agostinodublino138722 now! 😅😳
I made one just like this over 50 years ago. Fun to see it resurrected! The reason the 'blued' blades work better is because they have a selenium coating. You can put the point of the safety pin directly on the blade with those... no pencil required. Thanks for this vid!
Great Brie, Another project to do with my great grandson. Thanks so much.
pierre from New Mexico
I like how clear and easy to understand your vid was with a bit of history thrown in.
They did this in Masters of the Air! Awesome video.
This is exactly the kind of plan I was looking for. Years ago I found plans in a real old boy scout manual that used the cardboard tube and cats whisker, but it used a galena crystal. I think it also used varnish coated wire and the varnish was removed from an arc that the tuning arm traveled.
the razor blade and the cat-whisker or in this case the pencil "rectifies" the signal that is received. You can use an old Diode that just about anything electronic has a number of. The part usually has a symbol on like this →⊢
I love the emergency siren in the back ground wile your heating the rasor
I tried to make one of these a while back with a kit and couldn't get it to work. Really tough for some reason.
Bre I'm glad that you actually showed some "failures" along the way on this one. Keeping it real and showing that electronics aren't always a perfect science :)
HERE HERE, WELL SAID.
All you need are these.... Later in the video.. and these and these and these and these and these and these.
Cubejam And in your case... You'll need a brain.
Cubejam LMFAO
You MUST have a CRYSTAL earpiece/ headphones! This is crucial to the functioning of the foxhole radio!!!!
No, the high impedance headphones for other stuff works OK on this.
I made one of these once when I was in grade school. I bought a kit and put it all together. I was super proud of myself!
Just wonderful
Learned to make them in the scouts back in the 70's.
2:33 they found you, bree...
Great Job. Your dad, McGyver,would be proud. I really like the fact that you actually go through some mistakes and show people it's not a one shot deal. Thanks for sharing. Great Post.
Haha sound like mike francesa when he played the radio station!
This was one of the best videos on a diy radio to date!
I made this 14 years ago when i was a child. It really works.
I used slightly different things but the principle is the same. Its fun and sometimes usefull in certain situations
Like a MacGyver! AWESOME!!!
My brother did this when I was a little kid ,and it worked! 5-yr old learned electronics! Gotta love big brothers (even when they hit you for touching their stuff).
XD trying calling in and say "I'M USING A RADIO DONE BY GI'S IN WWII!" "Who is this guy?" "I CAN'T HEAR YOU,THIS RADIO IS SOFT!"
"...-,-"
This is extremely well made for 2007.
better product than the makerbots
Yes the number of coils will affect the tuning frequency.
Using a ground maximizes the potential difference between the radio wave and ground. In other words it makes the signal bigger.
Heard the toilet paper companies are getting rid of the tubes. Then what?
buy a radio
Easy, measure up an existing tube while you can, and make a replica tube out of printer/copier paper. Or, there is nothing to say you can't use plastic waste pipe, or even a small medicine or drink bottle. The tube doesn't even have to be of any specific material. You could even get more adventurous and dispense with the paper tube altogether and build a simple frame antenna, but I digress.
Him lighting the torch with sirens in the background is absolute comedy gold
Page not listed or has been moved?!?!?!
Learn nothing there!
late,but:cdn.makezine.com/make/wp_foxholeradio.pdf
Hey, we love your video! My son and I enjoyed it very much and the best part, it worked! Keep up the fun stuff. Many thanks!
Warning: This may turn out to be a Fox Talk Radio :)
That's still a FOX Hole radio... Not to be confused with an Ass Hole radio...
I and my father did it when I was young, in the sixties. Very nice to see it again.
You can use pipe for tap water, you can use a gas pipe, you can dig a whole in your garden and dig in a big metal plate to which you connect the ground lead wire.
AWESOME! It works good! It's neat how the heated blade makes it work as a diode.
it is the rust spots that make the good connections.. different size rust spots get different stations. you can get blue blades from crystal radio parts supply.
I built that today and it worked ! Thanks for posting
Thank you really, I finally understand the simple radio structure.
This is so high quality for 2007 damn
@fifthStitch The ground wire is for preventing you from getting shocked from static electricity. You COULD run it without one but it you could get electrocuted or at the very least zapped when the electric components built up enough electricity.
You could just attach the ground wire to anything metal that will absorb the electricity.
@lukasm14 this device shown is an AM radio. 102.6 MHZ is in the comercial FM band, where transmissions are in a different format. That Format is Frequency Modulation. Amplitude Modulation is "detected" by the diode action of the "cat's whisker" or, razor blade/pencil tip combination. Frequency Modulation, is deteted by a more complex method, and requires more complex equipment.
The razor blades had to be rusty or corroded so the contact point ( a bent wire or safety pin) becomes a diode. A very good diode was a green penny or other corroded coin. I finally did it with a galena crystal which is like the tiny crystal in a 1n34 diode. Which works very well.
Rofl the Cat6 wire
On a serious note, bluing is a process by which carbon steel (non-stainless steel) is coated with a specific iron oxide that inhibits rust slightly, but even more importantly, allows the metal to hold oil better to further prevent rust. The result is an item with the strength/etc. of carbon steel and the ability to not rust easily like stainless steel. Another widely used option in guns, but less so in blades, is Parkerization, which is similar but grayish and phosphate-based.
The pencil lead / razor blade combo is a basic diode, allowing the current to flow in only one direction.
@yasowhatup it is the air capacitance of the air coil. it is very low, however, the inductance of the open air coil is also very very low. thanks for you question
I live in Africa so I didn't really expect to hear anything as there were few radio stations: what I heard was electric sparks in the earphones though. Thanks to you, I will redo the experiment.
"Blue" razor blades had a silicon coating so they wouldn't rust. This was in the days before stainless steel was cheap enough for blades. You can still find a few in antique shops and on-line.
Nicely done! By the way, the talk radio is Mike Francesa of WFAN in NYC. One of the smartest sports reporters ever. He's syndicated, so not sure what station it was.
Sounds suprisingly good.
500 degrees is the temperature steel turns blue.
If you heat steel to red (called super heat) and let it slowly cool, the metal will be softened.
if you heat steel to red and quickly quench in water, the steel becomes very hard but brittle.
(crystalizes).
So, to get optimal strength, steel is first crystalized then shined up with abrasive and then reheated till blue. Blue is the strongest.
The quickest way is to quench in oil, which cools down to 500 and turns the object blue.
bluing is a process of heating and cooling that not only strengthens the metal but also does something to the internal electron configuration.
Yes u were correct about the type of Metal Treatment. I think its called "negative resistance". The coil is the antenna. The razor blade is the oscillator.
Cool project. Easy to make tunable. Just move the paper clip on the right to the center of the coil and stretch out the paper clip so that it rests on the coil with spring like tension. Make the coil almost twice as long. Use the edge of a metal file and remove about an 1/8" strip of enamel coating from the magnet wire. Tune by moving the paper clip across the coil to tap the coil in different places. :)
Nice! Glad to see you had a fire extinguisher on hand.
One safe way to heat the blade is on an electric stove. Lay the blade on one of the elements, turn in on high, wait until everything is glowing nice and amber / orange, then turn the element off.
This might not get the blade quite hot enough to temper / oxidise - but its worth a shot.
nice yesterday i started making this, my dad had some old world war 2 german razor blades so i took one. I made my coil with 300 turns, and used my washing line as an antenna and it works GREAT!
cool video,my uncle who passed away a few years ago like making this kind of stuff
would wire straight from an electric motor work?
how did you tune the coil? did you remove varnish or add taps?? I don't understand
If you can't get hold of a high impedance ear piece like the guy uses in the project you can also use an old cord phone as a speaker. Just take the cord out of the phone where you would dial, leaving you with the hand held part and cord coming out of the other end. Strip the wires and match them up. (There'll be four wires, so you can either use trial and error to find the right two or google it (: )
10 years later, we may be needing to make these ourselves
i like how, as you were getting ready to fire up the torch to heat up the razor blade, the sirens got closer.
My father made this radio in WW2 in the Netherlands. The Germans forbade people to have radio's. This one did not need power and he could use the line that his smother used to dry clothes with as a antenna. There were broadcasts from England especially for people in Holland to help them keep up the spirits and remember that help was on the way.
BTW, Bre, The station you received was WFAN on 660 kHz. Happy Listening
i remember over 10 years ago when I watched this, there was a lot i didn't understand from this video
Totally awesome and simple. Beginner hams would totally dig this. Perhaps a safer substitute for the burned razorblade, but otherwise, I totally dig it.
btw also if you use an audio jack and connect to + and - terminals you can use your computer speakers. Which is way more convenient as you can adjust the volume and you dont have to use the earphone
I'm a radio collector, thanks! I'll try this. Cool stuff.
I Googled this a lot and discovered this radio lacks a bar across the wound wire to tune in different stations.
To make a speaker for this google this exact term with quotes :
"Making High Impedance Headphones With less than 5 bucks"
Also check this out for making radios, google this exact term with quotes :
"Building a simple crystal radio." That shoudl bring you to Sci-Toys website, many pages about building different radios.
The drill press will work really well, just reduce the speed. You don't show the entire press, but it looks like the type that has an adjustable drive belt. If it is, just move the belt to a lower speed (a speed you would typically use when drilling metal).
Real cool! I watched it twice and that looks like a real cool weekend project.
you don't need too much heat to blue the steel. A simple pocket lighter will ussually do the trick.
I used to build these as a kid. They are an excellent way to learn about how radio signals can power devices.
@Tcosp Assuming the AM station is transmiting in stereo, if two of these devices where made, each with its own antenna, razorblade/pencil lead combo..etc, with earpieces....and one was tuned slightly above the frequency chanel in question, and one slightly below, then yes....stereo effect could be achieved! It would have poor stereo seperation specs due to the poor selectivity of this design, however, it would technically work.
Heat treatment to blue changes the metal from hard and brittle to springy. The color is a product of oxides.
@LUVITALL9 Razor blades are excellent in crystalline structure."Bluing" or oxidizing them in extreme heat, interferes with that structure.The interface point of this surface, and the semi-conductor characteristics of carbon, in this case, graphite in the pencil makes for a diode effect, which detects, or demodulates the am signal to an audio signal. make your antenna as long as possible. At least 50 feet for best results!
what a nice project, i will try this sometime.
The magnet wire has a coating on it that will prevent it from making the connection. If you still want to use the wire to connect the paper clips, take a lighter and hold the end of the wire over the flame until you see the coating burn away. It only takes a few seconds.
great video, reminds me of my younger days and just getting started. you also wear you shirt the way i did then...and well now.
@gomenaros One; safety, built up static electricy, two, its part of the antenna that uses ground radio frequencies (RF) to improve your signal.
Similar principle, they would wind wire on nails dipping the nail in wax after each set of turns then they would put the nails in a can and lightly cover the open end of the can with foil they usually got from candy wrappers. There's also a way to make a small speaker with charcoal and a small metal cup they would make on a hot stove.
That is soooooo kool!
I built a superheterodyne radio in high school and that took days in class to solder up.
I didn't know that this was possible though!
Oh well back to my 3d printing duties
you can hear the fire trucks and police on standby at 2:33 waiting for you to blow the place up. But you have certainly inspired a new weekend project!
@oneofy
Any metal object that's long enough has current induced in it from the radio waves traveling through the air. You could make a radio just by attaching a very sensitive earphone to an antenna of some kind, but then you wouldn't be able to select frequencies. It would only work if you were very near the transmitter of a large radio station. The coil and the crystal oscillate at a certain frequency and that allows you to select one specific station.It's called a tuned circuit.Look it up. :)
you are the man! a "macgyver" radio...that it!i finally found my jota-joti project topic!
thanks!
@kargocult I have eight uncles who were in WWII, they all had made foxhole radios and they showed me how to make one in the sixties. They could adjust frequencies and listen to many stations on the other side of the world, especially at night. They used 6 volt jeep batteries.
TH-cam algorithm, you fool! I found this video not in my recommendation, but in the results i searched.
The wire that is connected between the paper clips and the razor blade--is that also the magnet wire or a different kind of wire?
Great! The world desperately needs people like you.
if you have a fire place use something to hold it in the flames, BBQ, or a stove should be able to do it to if you hold it on the burner at a high enough temp.
PDF is Portable Document File its basically an extension used as .pdf along with the file name for example documen.pdf. Its viewed with Adobe reader. You can find tonnes of books on internet using the same format.
Cool rainy day project to give a kid ...
No! They would eiher cut them selves or get shocked. Really, what kid would want this when they get cell phones and internet?
@SolgerLemp acutally....moving the pencil has little effect of changing the channel....changing the length of the wound coil/wire changes the channel...However, this primitive radio does not have an ability to focus its ability to listen to a single channel very well, it is said to have "poor selectivity". It basically listens to whatever channel happens to be nearby, that has the most energy signal.
so you don't need like a germanium diode like in a crystal radio???? This is amazing.....no, it's more than amazing....it's MYSTICAL
i remember a project like this when i was a kid in the boy scouts. very educational
The advent of stainless razor blades was actually a big deal, made possible by metal technology that allowed the stainless steel to actually hold a decent edge. Usually (afaik) bluing is actually done with chemical aid, but apparently heating it like crazy can oxidize it too?
So where did the GIs get earpieces? And what did they usually wrap the wire around? Just curious. Thanks for the video!
Nice! I made one of those for my History of Broadcasting class back in college.
When WWIII lands home, I'll be glad I learned how to make one of these!
01100110 01110101 01110010 so true