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Crystal Sets. [message #25875] Sun, 06 August 2006 06:21 Go to next message
telegraph.hill is currently offline  telegraph.hill
Messages: 75
Registered: May 2009
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Has anyone else ever built a crystal set? I had one when I was a kid, but they were well out of fashion then. The one I had belonged to my Dad.

I wonder if you can still buy them.

Re: Crystal Sets. [message #25876 is a reply to message #25875] Sun, 06 August 2006 10:43 Go to previous messageGo to next message
Wayne Parham is currently offline  Wayne Parham
Messages: 18669
Registered: January 2001
Illuminati (33rd Degree)

Yes, there are crystal radio kits out there. You can also easily build them from scratch.


Re: Crystal Sets. [message #25877 is a reply to message #25876] Sun, 06 August 2006 23:36 Go to previous messageGo to next message
Paul C. is currently offline  Paul C.
Messages: 218
Registered: May 2009
Master
Yes, but I cheated and used germanium diodes instead of a real galena "crystal" and safety pin ("cat's whisker"). Check out the galena crystal and cat's whisker "Philmore Mounted Crystal Detector Stands" on this page:

http://home.earthlink.net/%7Ewb5rex/xtalman/detectors.html

Another thing to use for a detector was an old fashioned double edge razor blade, in particular, the (Gilette?) "blue blade". Touching the tip of the safety pin (or pencil lead) to the blue area, right next to the silver area would supposedly act as a detector. Those old blades no longer exist.

http://www.geocities.com/safetyrazors/blades/DEBladePage.htm

Makes you wonder who first got the idea... "Hey, let's take a razor blade and a pencil lead and..."

You think I jest?

http://bizarrelabs.com/foxhole6.htm (as a kid I had the book on this page "All About Radio and Television")

http://www.bizarrelabs.com/foxhole8.htm

And you had to have an oatmeal box to wind your coil... hah!

Here's the classic Quaker Oats crystal radio.

This site has lots of links, kits, plans, etc:

http://www.midnightscience.com/

http://www.midnightscience.com/catalog5.html

You can literally build this loop antenna, add an earplug and diode across the variable capacitor connections, and make a crystal radio from it:

http://www.mtmscientific.com/loop.html

Here is the correct diode, a 1N34A. You used to be able to buy a bag of these at Radio Shack for a buck or so.

http://www.mtmscientific.com/diodes.html

Just google "crystal radio" and you can find plenty of sites.

This one, Dave Schmarder's site, has both AM loop antennas and crystal radios:

http://www.schmarder.com/radios/misc-stuff/loops.htm

http://www.schmarder.com/radios/crystal/30.htm

Dave's crystal radios are very sophisticated. In fact, they are the most sophisticated crystal sets I have ever seen. Amazing!

http://www.schmarder.com/radios/index.htm



Re: Crystal Sets. [message #25878 is a reply to message #25877] Mon, 07 August 2006 09:21 Go to previous messageGo to next message
telegraph.hill is currently offline  telegraph.hill
Messages: 75
Registered: May 2009
Viscount
Thanks for all this information and links!

Yes - I am tempted to build my own crystal radio from scratch - just for the fun of it.

It's a pity they're not making the germanium crystal diodes any more... I guess they're just too expensive to produce, and there is not the demand.

Amazing that the POW's built crystal radios - I suppose it made perfect sense, then they could find out what was going on.

It's amazing that you can knock a radio together with just a few simple bits and pieces.

Re: Crystal Sets. [message #25879 is a reply to message #25878] Mon, 07 August 2006 11:20 Go to previous messageGo to next message
Paul C. is currently offline  Paul C.
Messages: 218
Registered: May 2009
Master
There was a secret mission, known as Mis-X (There is a book about it) where supplies were shipped into prison camps. Razor blades were magnetized so that when floated on water (you can float a double edge blade on the surface tension of water) the arrow on the blade pointed north.

Playing cards could be split and inside a portion of a map. All 52 plus jokers could be laid out to make a map of Germany.

There were brothers that before the war were HAMs. They had designed a transmitter/receiver that used the same parts for both, just a switch was thrown to alter the circuit from transmit to receive. It used a single miniature tube. They had made up a model name for it.

The brother in the prison camp wrote to his Uncle Samuel in Washington and that his brother be contacted to get him what he needed. Somehow someone in the Post Office caught on to the address, and routed the letter to the War Department, and it eventually ended up at Mis-X. They contacted the brother who knew exactly what was wanted. He showed them how to make up a kit of parts and schematic.

The kits were put in hollow aluminum spheres that screwed together, and top company people at Spaulding stayed after hours and stitched coverings on them to look like baseballs. These were slipped into the prison camp as recreational goods.

And that is how 2-way radio was established with the prison camps.

Re: Crystal Sets. [message #25880 is a reply to message #25879] Tue, 08 August 2006 09:37 Go to previous messageGo to next message
telegraph.hill is currently offline  telegraph.hill
Messages: 75
Registered: May 2009
Viscount
Thanks for this! It makes really interesting reading! It's amazing how resourceful people have been under really difficult circumstances.

Have you done a lot of research into this kind of stuff?

Re: Crystal Sets. [message #25881 is a reply to message #25880] Wed, 09 August 2006 00:33 Go to previous messageGo to next message
Paul C. is currently offline  Paul C.
Messages: 218
Registered: May 2009
Master
No, just building crystal radios (and other electronics) as a kid.

Re: Crystal Sets. [message #25943 is a reply to message #25881] Mon, 04 June 2007 16:43 Go to previous message
randle is currently offline  randle
Messages: 179
Registered: May 2009
Master
I remember getting a kit when I was about 9 or 10. I had a blast putting it together, and my friends and I would play like we were in a POW camp listening for the Underground. Hogan's Heroes was on the TV at that time. (Yeah I have told my age here!)

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