[R-390] R-1981

[Tisha Hayes]

Quote:
"The R-1981 was a R-390A modified to bring out the 17 MHz, HFO and VFO
signals to the rear panel andto insert an error correction signal for
high-stability operation.  It was a part of the TSC-25communications system.
 The modifications were done using a kit of parts from The Technical
MaterialCorporation (TMC) under contract number 14385-PC-58. The
manufacturer of the R-1981 receiver isunknown.  If anyone posesses one or
knows of its history, send mail to the FAQ-Meister so we can share the
information.

When I get it in the lab, I'll take pics and post them on my web page. I am
fortunate that this example is in very good shape, possibly an 8 on the 10
point scale.
Any other info would be greatly appreciated."

Maybe some of this was for a DF setup or potentially some sort of doppler
correction scheme of the Air Force or NASA for satellite reception.

As we know, our beloved mechanical filter setup does not lend itself well to
certain DF applications (interferometry).

As has been mentioned, maybe the high stability option (17 MHz osc) was part
of a requirement for high speed data reception. Locking the receiver to a
NIST traceable or disciplined oscillator or some type. It seems that the
inherent instability of the other crystals might make that a challenge.
(when we are counting ppm's)

-- 
Ms. Tisha Hayes/ AA4HA
----------------
"I'll be a diode, cathode, electrode
Overload, generator, oscillator
Make a circuit with me." -- The Polecats