Re: geography nerds?

"mike weber" <fair****tfan@[EMAIL PROTECTED]
> wrote
> On Fri, 22 Feb 2008 16:30:34 +0000 (GMT), dbell@[EMAIL PROTECTED]
> ("David G. Bell") wrote:
>
>>This is, incidentally, how a crystal set works. A very strong radio
>>signal (helped by a long aerial), a diode as detector (the original
>>crystal), and the headphones which only responded to the audio. Oh, an 
>>a
>>tuned circuit so you could listen to a particular transmitter.
>
> Don't even need a tuned circuit; as i recall reading, various spots on
> the crystal can react somewhat differently.
>
> I once read a "scientific things to do for kids" book which included
> making a "crystal radio" out of a blue steel razor blade, a pencil
> lead and a safety pin.
>
> John W Campbell once published a little squib in Analog which claimed
> that US Navy radio operators using crystal sets Way Back When had
> discovered that adding a second "cat whisker" contact wire and feeding
> a low DC voltage to it improved reception - they had no idea why, and
> apparently it was an accidental discovery.
>
> What iw was basically an application of the transistor principle
> thirty or so years before the invention of the transistor.

Woo. As major as thinking up geostationary satellites, but not patenting 
the idea.

Karl Johanson