[R-390] 390A test jigs

[Steve Toth]

My understanding about the Manson labs receivers (I'm doing this of the top of my head, so help me out group if need be), was that Manson Labs produced and converted R390A's for NASA starting with the Apollo space program.  They also produced an in-field conversion kit so the conversion could be done on-site.  The conversion enabled the R390A to be used with external precision oscillators for precise frequency control and stability.  
After the conversion the R390A became an R-1247.  The only physical appearance difference was three additional BNC interface jacks for the external equipment mounted on a plate mounted on the rear panel below the standard IF output jack and above the terminal strip and possibly no nameplate designating it as an R390A (I happen to have unintentionally acquired one of these receivers).
So maybe this is one of the in-field conversion kits? - Steve  W7SJT"Always look for a positive solution then Improvise, Adapt, and Overcome"- adaptation of the U.S. Marine Corps motto
"Every day is an opportunity to challenge the achievement of your dreams"
"Success is not final, failure is not fatal.  It is the courage to continue that counts."- Winston Churchill


 

      From: Tom Chirhart via R-390 <r-390 at mailman.qth.net>
 To: W4QG <w4qg at cfl.rr.com> 
Cc: R-390 at mailman.qth.net
 Sent: Thursday, February 15, 2018 6:36 PM
 Subject: Re: [R-390] 390A test jigs
   
These are mods made by Manson Labs to the R-390/A..
73
Tom
K4NCG

Sent from my iPad

> On Feb 14, 2018, at 5:58 PM, W4QG <w4qg at cfl.rr.com> wrote:
> 
> All,
> 
> I acquired a set of 4 devices which appear to be test fixtures/jigs. They appear to be commercially made.
> They have markings similar to what would be found 390(A) modules.
> Stamped on them is "R390A" "CODE 26916" and the part numbers 150-017274, 150-017275, 150-017276, 150-017277
> I've looked through my meager documentation and can't find any reference to these.
> Can someone give me some info on them?  (pictures available if anyone is interested)
> 
> Thanks,
> Paul W4QG
> 
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