[sdiy] Modular Theremin or Heterodyne VCO

[Mrs. Rectangular]

Hello to all other users of sdiy. I have been reading many of the archives and doing a lot of web searches about several ideas, and I just though it was time to ask...could someone point me in the right direction or the ideal method for setting up a theremin type device in a modular format? I would like to use antennas that create control voltage to then plug into a VCA and a VCO that would employ a heterodyning principle.