[R-390] R-1247 Manson Labs

[Tom Bridgers]

Your  R-390A has been modified by Manson Labs and is now called an R-1247..
The receiver was modified to accept an external frequency synthesizer (there
should be a couple of sealed relays inside the radio where the local
oscillators connect to the mixers and extra connectors on the backplane)

Provided the relays are still there, you don't have to reconnect the
oscillators to the mixers. The default position is internal LO's. Manson
Labs made the synthesizers, and the entire system was a double-diversity
system, even the transmitters
(modified T-368's) were locked into the same time base on the synthesizers.

The above is an edited post from a year or so ago...
-tom