[R-390] re cost reduction ect ect

[AI2Q]

Hi Bernie:

For your reference, you can see my R-390A product detector circuit at this 
URL:

http://users.adelphia.net/~alexmm/Prod_det/detector.htm

Vy 73, AI2Q, Alex in Maine
http://users.adelphia.net/~alexmm/ai2q.htm