Almighty Crystal Radio

A Triple-Ganged Crazy Crystal Radio
copyright © 2006 by Larry J Solomon

This circuit, of my own design, is my current winner for sensitivity and selectivity. Performance is truly astonshing. When used as a receiver connected to a fine sound system it outperforms several commercial AM radios that I have tested for sound quality.

Pay especial attention to the polarity of the coils when building this set. They are wound clockwise from top to bottom looking down on the coil. All the wire is 24 AWG.

It is also important to use 500pF variables to tune the entire broadcast band. The more common 365pF units will work but will not tune the entire band. Note that the rotor sides of the caps go to ground (green clip in prototype). The stators are the ones with lugs attached (white, red, and yellow alligator clips in prototype picture).

 I added a level control to audio output because the output was too loud on most stations using the low level mag input on a receiver, causing distortion. The pot can adjust the level for best fidelity and pulls in almost any local station. An alternative is to use a high level input on the receiver. In that case, omit the pot and P2.


Here is the prototype. The coil was wound with my coil winder, of course.

Now some photos: