PDA

View Full Version : Foxhole radio

Gemini
08-February-2009, 01:54 PM
Has anyone here ever built? If so, what did it take you to make it work? Mine just refuses to pick anything up.
tdvance
08-February-2009, 06:41 PM
I tried as a child but it didn't work. The TV repairman (we still had radio tubes in our TVs then) said he built one once, and it worked. He said the secret was putting the pencil lead on exactly the right place on the razor blade--fraction of a millimeter off, and the station goes away.

Also, you need a high-impedance earphone (piezoelectric should work--the kind found in crystal radio kits). He looked at mine and told me mine wasn't enough...it was the magnetic coil kind.

I eventually gave up and bought a crystal radio kit--that one worked. You need a strong AM station close by.
peteshimmon
08-February-2009, 07:35 PM
Ha! Just dug out my Boy's Book of Crystal
Sets by W.J.May. A Bernards Radio Manual.
Dad got the parts for the first design which
worked well in 1961. There is a design using
two diodes giving full wave rectification
which should be louder.

Just a few more years now however, most
stations will just be a digital buzz in
the headphones shortly!
Gemini
08-February-2009, 07:42 PM
I tried as a child but it didn't work. The TV repairman (we still had radio tubes in our TVs then) said he built one once, and it worked. He said the secret was putting the pencil lead on exactly the right place on the razor blade--fraction of a millimeter off, and the station goes away.

Also, you need a high-impedance earphone (piezoelectric should work--the kind found in crystal radio kits). He looked at mine and told me mine wasn't enough...it was the magnetic coil kind.

I eventually gave up and bought a crystal radio kit--that one worked. You need a strong AM station close by.


If you're not in that "sweet spot" will you hear anything at all?
Veeger
08-February-2009, 07:43 PM
I'm not sure which design is a foxhole radio, but I did successfully build the pencil lead, razor blade radio as a kid. I was amazed how simple it was. It picked up one local radio station.
Gemini
08-February-2009, 09:23 PM
I'm not sure which design is a foxhole radio, but I did successfully build the pencil lead, razor blade radio as a kid. I was amazed how simple it was. It picked up one local radio station.

I still hear nothing at all.
tdvance
08-February-2009, 11:32 PM
If you're not in that "sweet spot" will you hear anything at all?

maybe a hum. I got lots of 60-cycle hums.
BigDon
09-February-2009, 12:49 AM
Anybody have a link to a razor blade radio?
HenrikOlsen
15-February-2009, 01:31 PM
First hit with Google had this link (http://bizarrelabs.com/foxhole.htm) which looks good.

Gemini, are your earphones high impedance or magnetic coil?
Gemini
15-February-2009, 01:53 PM
First hit with Google had this link (http://bizarrelabs.com/foxhole.htm) which looks good.

Gemini, are your earphones high impedance or magnetic coil?
I'm not entirely sure, they 're made by Motorola in the 60's or 70's. That link above was the basic plans I was going off of.