[Milsurplus] Foxhole Radio - conclusion

[J. Forster]

Hi Al,

John Franke sent me some V-I plots off-list. They show very little
difference between a sweet spot on a Galena crystal and a Ge diode.

Best,

-John

===========



> Mike,
>
> Yes, I have.  Overall, this detector is not very sensitive, get
> something going with a germanium diode, so you know you're in the
> ballpark.  One of the tricks is to scratch part way through the bluing
> on the blade.  Some suggest there is selenium, a semiconductor material,
> involved in the coating.  There is, of course, carbon, another
> semiconductor, involved in both the pencil lead and the high-carbon
> steel.  I've had success with the hardened edge of other, non-blue,
> blades.
>
> There's potentially useful info on my site here:
> http://www.skywaves.ar88.net/xtal/xtal.htm
>
> I highly recommend the PGXS circuit if you're going to wind a coil.
>
> Build a crystal set.  It's good for your soul,
>
> Al
>
> On 8/6/2012 11:58 AM, mstangelo at comcast.net wrote:
>> Has anyone ever tried building one of these foxhole radios?
>>
>> I started my journey inot electronics, like may others, by building
>> crystal radios.
>>
>> I got my crystals from a neighbor who was an electronic technician . My
>> first crystal was in a bakelite case. I forget the number but I still
>> have it
>> somewhere. The tapped coil was built on a schellaced toilet paper roll.
>> My headset was a high impedance crystal earpiece.
>>
>> I lived in Queens New York at the time and could easily pick up WCBS
>> 880.
>>
>> I read about the foxhole radio which used a Gillette Blueblade and the
>> pencil graphite as a detector. The graphite was held with a safety pin.
>> I got hold of the blade and graphite and tried it but could never get it
>> to work.
>>
>> Has anyone hasd success with this type of detector? If I could get my
>> hands on a Blueblade I'd try it again.
>>
>> Mike N2MS
>>
>>
>> ----- Original Message -----
>> From: Hue Miller<kargo_cult at msn.com>
>> To: milsurplus at mailman.qth.net, tetrode at googlegroups.com,
>> Wireless-Set-No19 at yahoogroups.com
>> Sent: Sun, 05 Aug 2012 22:54:12 -0000 (UTC)
>> Subject: Re: [Milsurplus] Foxhole Radio - conclusion
>>
>> The opinion was also expressed that soldiers have often have time on
>> their
>>
>> hands, where boredom is an issue: thus, they would relish some activity
>>
>> like the opportunity to build 'foxhole radios'.
>>
>> <snip>
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>
> --
> Al Klase - N3FRQ
> Jersey City, NJ
> http://www.skywaves.ar88.net/
>
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