[AMRadio] WB4AM product detector answer

[CL in NC]

Well, there is a lot of info on the web on the science and reasons for product detectors, some including more math than you want to deal with.  I believe the plus side to the PD is that with an AM/CW basic design receiver and a simple diode detector,  you will notice that a strong SSB of CW signal may not demodulate properly since you don't have enough BFO signal for the level of the incoming RF.  Most times, the AVC in an AM receiver has to be turned off and the gain controlled by the RF gain pot in order to maintain a balance between the BFO sig and the incoming SSB RF, the same for CW.  The SX101 uses a multigrid  6BY6 as a PD, an in this SX100, the builder used a 6BE6.  The circuits are similar, but the components are greatly different.  Pretty sure he copied the SX101 set up, and tie in points.  Where he came up with this exact circuit is unknown, and his changes to the 6BJ7 circuit in order to tie it all in without the use of an extra wafer on the function switch was pretty ingenious.  It did make it fun to trace out all the wiring to figure out what the builder did though.

Charlie, W4MEC in NC