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Old 03-26-2012, 02:18 AM
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jake jake is offline
Senior Member
Join Date: Nov 2007
Posts: 169
next generation crystal radio

So once I felt confortable with a typical crystal radio and could tune most of the stations on the high end of the AM band. I started to put together a Tesla Resonant Transformer. This is part of the crystal initative on the Dollard Thread.

Below are the results of three generations of coil formers. The former you see is stout and will allow you to pull the wire tight while winding. I am still missing the primary, topload, capacitors. BUT

It blows my crystal radio with tuning capacitor away. Attached are some pics. The DSO pic is my night time reception it came down from 1.3v earlier this afternoon with +4v peaks. This got me excited for a while but then I realized that my scope maxes out at 1MHz. Your looking at 1.62MHz rectified
audio. 100us/div and 50mv/div, the yellow line is 500mv.

Do these numbers mean anything or is working out of the range of my scope produce garbage numbrs???

And finally I was able to dimly light an LED in line with the germanium diode.

Any one know how to hook up a joule theif without loading down the circuit??

It looks like there is enought there to run one but doing it without loading down the circuit is eluding me.
Attached Images
File Type: jpg dso pic.jpg (52.2 KB, 25 views)
File Type: jpg TRTnew former coil 004.jpg (31.2 KB, 58 views)

Last edited by jake; 04-29-2012 at 08:05 PM. Reason: smaller pictures
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