[R-390] Frequency Synthesis on the R-390/A

[Steve Toth]

Tisha
I would also be interested in a copy of the docs you found and pay for the copying and postage.
 
I have what is possibly an R-1981.  It's an early Collins with the front panel that takes a long Collins tag instead of the Manson Labs tag, and it has the 17Mhz input / output mods installed.  The previous owner picked it up at an estate sale in Florida of a ham that worked for NASA and claimed it was formerly used in Vietnam.  It's either a NASA R-1247 with a changed out front panel (most likely - although it has no Manson labs markings on any of the modules), or an R-1981 - I'm just not sure which.
 
Per the R-390A FAQ page - The R-1981.
"The R-1981 was a R-390A modified to bring out the 17 MHz, HFO and VFO signals to the rear panel and to insert an error correction signal for high-stability operation. It was a part of the TSC-25 communications system. The modifications were done using a kit of parts from The Technical Material Corporation (TMC) under contract number 14385-PC-58."
 
And from a past email I received off list a while ago from Tom, NU4G (thanks Tom!):
 
"I also have the two synthesizer decks for your R-1247 - I was supposed to also get an R-1247, but it never materialized.**

**(Which is just as well.  Imagine dialing up a freq on the receiver, then cranking on TWO boxes - one for MC and one for KC, to tune to a freq.  The GRC-129 system was an interesting contraption that used two of your receivers controlled by the synth - the pair was set up in diversity mode. The transmitter was a highly Manson-modified T-368 that was redesigned for SSB only.  "Contraption" is a good system description, as is "haywire."  There were better things in production at the time, who knows how the contract for that system was ever approved. heehee Nonetheless, it's still interesting.)

 
-- Steve 






Woodinville, WA
In any hobby there is no such thing as "over kill" - just budget limitations.


--- On Fri, 8/14/09, Richard Green <k7yoo at yahoo.com> wrote:


From: Richard Green <k7yoo at yahoo.com>
Subject: Re: [R-390] R-390 Digest, Vol 64, Issue 21
To: r-390 at mailman.qth.net
Date: Friday, August 14, 2009, 10:28 AM


I thought that version of the R390A was called the R 1247. I have one that was done by Manson Labs and it has the most linear PTO of ANY Collins radio I have ever owned. I would like a copy of the docs on this version and certainly would pay for copying and postage.