[R-390] Synchronous AM Reception

[Fraser Bonnett]

Having just recently got my R-390A back out of storage, I find myself
interested in MW DX'ing again.  I have re-read two articles on modifying the
R-390A to acheive carrier synchronous demodulation, and was wondering if
anyone has any experience with it, and if it is worth attempting:

An NRC reprint from 1992 uses:
    a coil of wire around the anode of V508
    100K (or 47K) resistor
    a 5-50 pf trimmer grounded to the carrier meter adjust nut
    a 47K (or 22K) resistor in series and connected to pin socket 1 of V505


Once it's set up, how do you use it, what effects do you observe.


Fraser, W3UTD