10/22/05 - I simply must build a working AM receiver.

I wrapped about an inch of the toilet paper tube with magnet wire and then super glued it in place.  After it had dried, I used a dremel to remove the insulation from one small section of the coil.  This will serve as the variable tap for the inductor.

I had figured that I would use this circuit

but when I hooked it up, It just didn't work.  So after a little messing around, I came up with this circuit:
 

and it works!  I have a 30 foot wire hanging out my window for the antenna, and I rigged the whole thing up on a piece of wood and a breadboard.  I can tune in about 2 radio stations, and the stations bleed together alot, but it works.  I am so proud!!! 

I added the extra inductor and the variable capacitor to increase the tuning range.  The scope is providing a "ground".  At this point I am listening to NPR. :)   here is some audio of the radio in operation. I tune it around so that you can hear some different stations with this super super simple circuit.

AM radio.mp3