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1010/ap

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http://www.solarbotics.net/library/circuits/misc_sound_tgray.html 20:46 (tech_notes#148)

for a home-made transistor: 20:40 (2006.07.12:6 research#21 tech_notes#147)

Instead of bothering with tiny wires, Brattain attached a single strip of gold foil over the point of a plastic triangle. With a razor blade, he sliced through the gold right at the tip of the triangle. Voila: two gold contacts just a hair-width apart.

The whole triangle was then held over a crystal of germanium on a spring, so that the contacts lightly touched the surface. The germanium itself sat on a metal plate attached to a voltage source. This contraption was the very first semiconductor amplifier, because when a bit of current came through one of the gold contacts, another even stronger current came out the other contact.

from:

http://www.pbs.org/transistor/science/events/pointctrans.html

software radio using below bt878 16:08 (2006.07.12:5 tech_notes#146 research#20)

http://www.domenech.org/homebrew-sdr/receiver-1.htm

also back to bt878 at 896000 samples per second (442 KHz usable bandwidth) 16:06 (2006.07.12:4 tech_notes#145 research#19)

http://www.domenech.org/bt878a-adc/index-decimator-e.htm

for baudline use and CPU noise analysis 16:01 (research#18)

http://www.wisdom.weizmann.ac.il/~tromer/acoustic/

minimal antenna: 14:41 (research#17)

http://www.vlf.it/minimal/minimal.htm

started experiments with baudline and stasi radio antenna 13:46 (research#16)

50 Hz power lines mirrored at 100 and 150 Hz

see also:

http://www.techlib.com/electronics/VLFwhistle.htm

and from http://www.vlf.it/kurt/elf.html

a number of obviously artificial signals seem to be sended out by some unknown sources permanently, created by electric currents flowing through the surface of the ground and only visible and hearable by using a sound card as a kind of "time microscope".

in context of ripper radio reception