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| Joined: | Nov 21st, 2009 |
| Location: | United Kingdom |
| Posts: | 182 |
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Hello everyone.
As some may know I have been working with various Germanium diode based detectors for a little while.
From my own perspective with very limited success.
The circuits both purchased and taken from on-line searches have never felt quite right to me.
The trouble with having a radio background is you tend to get stuck in the mind set of what should and should not work, so I tried to put this to one side and accept that we may not be chasing ‘radio’ signals in this field.
However, it’s grated on my mind all the time.
So today I have adapted a circuit to be both wide open to RF energy and to be functionally more correct.
This new circuit includes capacitors.
These basically are able to store electrical energy and release it.
The idea of the capacitors is to store energy as the AM radio sign wave goes from + peak to – .
Left to right: Antenna, short wire with loop, 1n capacitor, loaded to ground at 100k ohms, Germanium diode, again loaded to earth at 100k ohms, then a 2n2 capacitor (made up with two caps in my circuit)
Finally the whole device is mounted inside a tin and a wire (white) connects earth to the tin providing a screen.
The tin is then sealed with foil.
I have made a test and found it to be very smooth and sensitive.
http://www.box.net/shared/84ypkrz05r
No voices that I can hear but here is a 7min clip to give you an idea of the sound output.
I will start more intensive tests soon and report back.
Regards from sunny Sussex UK
Last edited on Mar 24th, 2011 05:00 AM by mikesndbs