[R-390] External product detector

[Gordon Hayward]

I built an external product detector with 2 MC1496 mixers. The crystal BFOs are for USB, LSB and one exactly at 455 kHz for zero beating AM stations. The BFOs are fed to the two detectors in quadrature (90 degrees apart) which are fed to right and left channels. The stereo effect on the noise is remarkable.


I also added a PLL FM detector and a precision diode detector for AM just because I could. I don't use them much. The box also includes a logarithmic voltmeter as a second S-meter for low signals.


A third addition was a CL-90 thermistor to slow start the 390A.


Cheers, Gord VE3EOS