The first time I tried this, it didn’t work. It was frustrating, but I just went through my materials, blued the razor blade and it worked. The second time I tried to get it to work, I couldn’t get a station, I just got buzz. I played with everything and finally figured out that the ground connection wasn’t very good. When I fixed that, I was able to hear sports talk radio! One of the interesting things is that it works better or worse depending on where you put the pencil lead on the razor blade. If it doesn’t work the first time, don’t give up! Every project you work on can have 100% success as long as you don’t mind mistakes and redoing things!
Download the PDF to get the full instructions! – PDF Link
42 thoughts on “Make a Foxhole Radio – Weekend Project PDFcast”
Comments are closed.
A ‘regular’ low impedance earphone will not work in this circuit. Find a high impedance [ 2000 ohm] or a crystal earphone . see link:
http://www.midnightscience.com/catalog5.html
To change the station, or tune it you’ll need a variable resistor. Here’s a way I found to make one from a sheet of paper, pencil and 2 paperclips. The black rectangle needs to be very dark.
http://img187.imageshack.us/my.php?image=0915014211gs2.jpg
^– taken with my phone.. so bear with the quality.
Move the paperclip to tune the radio.
arvash, I’m pretty sure you mean a variable capacitor
thats what most radios use for tuning
@mikiex ahhh I see.. if that’s true than my variable resistor shouldn’t work >>… You can make a variable capacitor by using a book and 2 sheets of aluminum foil. Seperate the two sheets of aluminum foil by a page or so. Press the book together for higher capacitance, release a bit for lower capacitance. I think I get why you can’t use a variable resistor here.
must some telepathy going on. I was just thinking about the razor blade radio I made 45 years ago. You could buy blued razor blades then. it worked quite well considering
texbrandt
We used to do something like this in 1960’s.Worth doing this again to show the kids with iPod!
Hi, I want to try to make it but can I use a razor like this one
http://www.sxc.hu/pic/m/b/br/brokenarts/435178_razor_blade.jpg
and thanx
Much easier to wind the magnetic wire with hand drill. Mount a dowel on the bit and toilet tube on the dowel and wind away. A lot less tedious and no wild windings like with that drill press in the video. If you can’t heat up a razor to blue it you can always try a rusty razor,(just don’t nick yourself with it… lock-jaw and all that) if I’m not mistaken its the oxidation of the metal that allows the process to work.
ggfffffffffff
I get very interested with this project but i’m not really sure about how to make the ground connected well.Could you explain about this to me?Thank you.
Is it possible to blue the razor using a stove top?
don’t give up! Every project you work on can have 100% success as long as you don’t mind mistakes and redoing things!http://www.astrabeds.com/adjustable-beds.html
don’t give up! Every project you work on can have 100% success as long as you don’t mind mistakes and redoing
http://www.astrabeds.com/adjustable-beds.html
Hi guys,
A friend who is a blind ham showed me this video on YouTube. Unfortunately you got is wrong. The razer blade is supposed to be a sharp point similar to the cats whisker used on the original crystal sets on the galena crystal. The sharp edge is touched to the graphite, not the way shown in the video. The color of the blade is unimportant and the heating is unnecessary. With a close (strong) AM station, you don’t even need the coil. Since it isn’t resonated with external capacitance, or with some kind of a tuning arrangement like a sliding contact to vary the inductance, you will hear everything close to you, AM that is.
Regards, noskosteve at Yahoo
I also don’t understand why you take time to show errlrs (winding)
pls i am trying to fix this kind of radio and it is not working , i dont know that kind of razor you are talking about , can you pls send me a pic of the kind of razor that is and the best way to put up this kind of radio, and if there is a possiblilty to put up one that can get fm stations, matobidyke@gmail.com
this Mathias Jnr, writing from Nigeria.
…thanks
The bluing on the original blade was a thin form of oxidation used to keep it from immediately rusting. It’s the same principal used on most firearms to slow rusting. Heating the thin steel razor blade oxidizes it. If the oxide is too thick it won’t work. The pencil should be fairly sharp and won’t scratch through the oxide.
The farther away the nearest radio tower, the higher the antenna needs to be. Any thin wire will work. A good ground can be metal pipes buried in the ground, water pipes usually work. Just stay away from the mains!!!
It is very important that all connections be good. Metal to metal.
As mentioned above the earphone is critical and should be high impedance. See the site below for alternative earphone suggestions.
If you can’t get the razor blade to work, another option is using a small germanium diode found in almost all
radios and TVs. Get one from a TV/radio repair shop. Use it in place
of the razor and pencil. It only works in one direction so play with
hooking it up. Or, ask the repairman for help.
This site has a lot of information on crystal radios:
http://sci-toys.com/scitoys/scitoys/radio/homemade_radio.html
Good luck and have fun
pls i am trying to fix this kind of radio and it is not working , i dont know that kind of razor you are talking about , can you pls send me a pic of the kind of razor that is and the best way to put up this kind of radio, and if there is a possiblilty to put up one that can get fm stations, matobidyke@gmail.com
this Mathias Jnr, writing from Nigeria.
…thanks
Where I have to fix the “Antenna”?
It is the bluing, oxidation, that makes the razor into a crude diode. You need hi-impedance ear phones (2,000 ohm) for them to work well. Xystal radios only pick up AM stations.
As a kid I once made a radio from a germanium diode from a TV repairman, WWII surplus earphone, window screen antenna and old gas pipe for ground. You couldn’t tune it. It played the strongest station in Tulsa so loud I had to put it under my pillow at night.
hi, so i did this project and it does work but i only hear the buzz . i am using my guitar amplifier instead of headphones , and i heated the razor blade at the cooker flame but i think the grounding or the antenna ( or both) are the problem , the antenna is only 3 metres long so is the grounding which i connected to a radiator pipe ( it was cold) . what do you think is the problem ? please help
can i use a rusted blade instead of blued?