Help - I need a schematic for an early Atwater Kent Model 3975 breadboard. Any schematic for an early set with variometer tuning would probably do. I particularly need to know how the second variometer was wired to make the set regenerative.

Thanks in advance, Frank.

You probably would be connecting the second variometer as an "antenna tuner", or "matching inductor". In other words, it should be approximately conencted in parallel to your first variometer. If the radio has a fixed condensor, the second variometer does your tuning selection.

I have included a few crystal radio pages that have enough design theory in them to allow you to connect the second variometer into the circuit effectively, as there are more than one way to connect a crystal set. There are also a few items that will allow some changes to the circuit if needed.

http://www.antique-radio.org/class/class.html
http://www.connix.com/~harry/drcrystl.htm
http://www.midnightscience.com/

This last one has an excellent collection of circuit books that will give you other ideas. One even has a plan for a "Crystal FM" radio

While not exactly the specificity you wanted, there should be enough good information to allow you to experiment for best results.

: Help - I need a schematic for an early Atwater Kent Model 3975 breadboard. Any schematic for an early set with variometer tuning would probably do. I particularly need to know how the second variometer was wired to make the set regenerative.

: Thanks in advance, Frank.

:Help - I need a schematic for an early Atwater Kent Model 3975 breadboard. Any schematic for an early set with variometer tuning would probably do. I particularly need to know how the second variometer was wired to make the set regenerative.
:
:Thanks in advance, Frank.