eHam

eHam Forums => Elmers => Topic started by: WALTERB on March 24, 2013, 03:13:55 PM



Title: Crystal / Foxhole Radio / POW earpiece construction?
Post by: WALTERB on March 24, 2013, 03:13:55 PM


I came across this article about Richard Lucas, who was a POW in Vietnam.
He built his own earphones out of wires, nails , candle wax, and clothing.
I can’t find any other documentation online about it other than this link (see below)
I was wondering how you would build an earphone for a foxhole / crystal radio with only material you would have available as a POW as he did?

Thanks.

http://bizarrelabs.com/foxhole.htm



Title: RE: Crystal / Foxhole Radio / POW earpiece construction?
Post by: KB4QAA on March 24, 2013, 03:38:44 PM
I've never read about any of the Vietnam POW's building radios.  My impression is that they were incredibly closely watched by their guards.

Here is the description from Wikipedia on how Lucas made an earphone.  It sounds quite plausible.

Quote
Richard built his earphones by binding four nails together with cloth then winding wire and dripping wax over the turns. After about ten layers of wire he placed it in a piece of bamboo. A tin can lid was placed over the coil of wire. The listener connected the improvised earphone to the foxhole radio and received three radio stations.



Title: RE: Crystal / Foxhole Radio / POW earpiece construction?
Post by: WALTERB on March 24, 2013, 03:45:21 PM
I've never read about any of the Vietnam POW's building radios.  My impression is that they were incredibly closely watched by their guards.

Here is the description from Wikipedia on how Lucas made an earphone.  It sounds quite plausible.

Quote
Richard built his earphones by binding four nails together with cloth then winding wire and dripping wax over the turns. After about ten layers of wire he placed it in a piece of bamboo. A tin can lid was placed over the coil of wire. The listener connected the improvised earphone to the foxhole radio and received three radio stations.



here is the quote from the article.

But what about the earphone?
Richard Lucas, who was a POW in Vietnam, built a radio in camp and was also able to improvise an earphone. He writes:


Four nails were bound together with cloth from our clothes.
Wire was obtained from wire used around the camp which I might add wasn't coated with varnish. It was bare wire, so we wound a layer and, using a candle, we dripped wax over the turns, which were spaced as closed as possible without shorting out (not touching). We repeated this process over and over again until we had about 10 layers of wire, which were insulated from each other layer by a strip of cloth and wax. Then we put this in a piece of bamboo and adjusted it so it was about a 1/32 of an inch from the end.

A tin can lid was positioned over the coil of wire and nails. Then connecting it to our "foxhole radio" (basic design as yours) we could here about three radio stations. Our antenna was the barbwire around the camp and the ground was wire laid along the ground to make up the ground. Best listening was at night and it had to be pretty quiet because the earphone was pretty weak. If we had a magnet to set up a bias on the coil, the volume would have been a lot louder."


And Mike Barnard points out that "the headphones were almost always acquired from a tank crew's radio operator, and often one side of the headphone was cannibalized for wire to wind the tuning coil while the other was used for listening."


Title: RE: Crystal / Foxhole Radio / POW earpiece construction?
Post by: AC5UP on March 24, 2013, 03:50:32 PM
Yeah, but the professor on Gilligan's Island built a maritime homing beacon out of a cocoanut and three shark teeth..........

Which is also how Yaesu built their first CW rig.   :o


Title: RE: Crystal / Foxhole Radio / POW earpiece construction?
Post by: WALTERB on March 24, 2013, 04:01:23 PM
Yeah, but the professor on Gilligan's Island built a maritime homing beacon out of a cocoanut and three shark teeth..........

Which is also how Yaesu built their first CW rig.   :o

don't forget Gilligan got his head turned into a radio..  (sad that I remember that.. )   ;D


Title: RE: Crystal / Foxhole Radio / POW earpiece construction?
Post by: KB4QAA on March 24, 2013, 04:09:36 PM
Yeah, but the professor on Gilligan's Island built a maritime homing beacon out of a cocoanut and three shark teeth..........


The Professor had a lot of lovely inspiration.


Title: RE: Crystal / Foxhole Radio / POW earpiece construction?
Post by: WD4ELG on March 24, 2013, 06:19:11 PM
More like the Professor had a lot of lovely DISTRACTIONS!  I used to DREAM I was on that island.


Title: RE: Crystal / Foxhole Radio / POW earpiece construction?
Post by: WALTERB on March 24, 2013, 06:26:11 PM
More like the Professor had a lot of lovely DISTRACTIONS!  I used to DREAM I was on that island.

When you go to sleep tonight try and dream about making a crystal radio speaker out of one of Mary Ann's coconut cream pie pans or something.  ;D
 


Title: RE: Crystal / Foxhole Radio / POW earpiece construction?
Post by: WX2S on March 25, 2013, 05:52:02 AM


I came across this article about Richard Lucas, who was a POW in Vietnam.
He built his own earphones out of wires, nails , candle wax, and clothing.
I can’t find any other documentation online about it other than this link (see below)
I was wondering how you would build an earphone for a foxhole / crystal radio with only material you would have available as a POW as he did?

Thanks.

http://bizarrelabs.com/foxhole.htm


I could imagine how to do this. Build a little electromagnet out of the wire and a small nail. Wax the cloth and use it for a diaphragm.

Or, you could do it as described:

Quote from: Richard Lucas
Four nails were bound together with cloth from our clothes.

Wire was obtained from wire used around the camp which I might add wasn't coated with varnish. It was bare wire, so we wound a layer and, using a candle, we dripped wax over the turns, which were spaced as closed as possible without shorting out (not touching). We repeated this process over and over again until we had about 10 layers of wire, which were insulated from each other layer by a strip of cloth and wax. Then we put this in a piece of bamboo and adjusted it so it was about a 1/32 of an inch from the end.

A tin can lid was positioned over the coil of wire and nails. Then connecting it to our "foxhole radio" (basic design as yours) we could here about three radio stations. Our antenna was the barbwire around the camp and the ground was wire laid along the ground to make up the ground. Best listening was at night and it had to be pretty quiet because the earphone was pretty weak. If we had a magnet to set up a bias on the coil, the volume would have been a lot louder."


Very clever.

73, -WX2S.