[R-390] R-1247 Nasa Receiver info

Thu Feb 25 20:44:41 EST 2010

I have one of these synthesizers with a Hallicrafters name tag. I have 
to check my storage but I seem to recall that it is the 1 MHz synthesizer.

I mentioned this unit a couple years ago on the Hallicrafters reflector 
and nobody was able to tell me anything about it.

If anybody needs it please drop me a line.

vy 73 de Heinz DH2FA, KM5VT

Meir WF2U schrieb:
> The  R-1247/GRC-129 receiver is the nomenclature for the R-390A receiver
> modified by Manson Labs.
> 
> The GRC-129 system was a high-stability diversity system used by NASA which
> had two R-1247/GRC-129 receivers.  These modified R-390A’s had other
> associated equipment manufactured by Manson Labs. The receiver was modified
> to accept inputs from the external frequency synthesizers which generated
> all the necessary LO frequencies.
> 
> The receivers can be switched over from internal to external LO operation
> and for this purpose had small relay boxes and LO in/out cables/plugs. 
> The IF output was utilized through an SSB converter (2 channel) which
> provided the demodulated audio output (the BFO signal was supplied
> externally from one of the synthesizers).
> 
> The CV-1693 is the 1 MHz step synthesizer and the O-1203 is the 1 KHz step
> synthesizer locked to the same frequency standard. With the 2 synthesizers
> the receiver is tunable within its normal frequency range in 1 KHz steps.
> The frequency still has to be dialed in the receiver, because the RF stages
> and mixers have to be peaked up at the frequency of operation. The receiver
> can be operated normally, too.
> 
> I used to have the synthesizers for the GRC-129 system and I still have the
> R-1247 receiver which works normally by itself - it has 2 tags: the system
> tag "R-1247/GRC-129 Receiver, Manson Labs S/N 48, contract #
> AF30(635)30962"; and the original R-390A tag: "R-390A/URR, S/N 1832,
> Motorola, contract 14-PH-56".
> 
>  Hallicrafters also made some of the synthesizers under contract, for
> Manson.
> 
> I also had another part of the same system, the O-1555/URC which is a
> synthesizer to set the frequency of a modified T-368 transmitter whose
> GRC-129 nomenclature eludes me. The component I never had is the SSB
> generator that was added to the transmitter instead of the original
> modulator deck. I also had some documentation on the synthesizers.
> 
> I sold all the accessories mentioned above maybe 10 years ago, with whatever
> technical documentation I had, except I kept the R-1247 receiver which I
> still have. It's usable as a normal R-390A without all the accessories.
> 
> I hope this clarified some questions. 
> 
> 
> 73, Meir WF2U
> Landrum, SC
> 
> -----Original Message-----
> From: r-390-bounces at mailman.qth.net [mailto:r-390-bounces at mailman.qth.net]
> On Behalf Of Mack Rogers
> Sent: Thursday, February 25, 2010 5:52 PM
> To: r-390 at mailman.qth.net
> Subject: Re: [R-390] R-1247 Nasa Receiver info
> 
> I recall seeing some surplus dealers and even a few individuals that had the
> complete AN/GRC-26D shelters with all the radio gear still intact but only
> the shelters and gear, not still on the truck.
> 
> Which brings up the interesting question of exactly why something that was
> supposedly for NASA use only would show up on the mil lists as being a
> standard military piece of gear? AN/GRC-129 shows to be a standard
> AN/GRC-26D with modifications? <big grin>
> 
> Could we be seeing one of those deals where NASA needed it but didn't want
> to pay the price tag themselves? I used to see train loads of brand new
> military heavy construction equipment, bulldozers and etc., going into one
> of our TVA nuclear plant construction sites. A few days later that brand new
> military construction equipment would roll out of the TVA shop repainted and
> renumbered as TVA property!? <grin, wink>
> 
> 73s
> N4VGB
> Mack Rogers
> 
>  
> 
> 
> 
> --- On Thu, 2/25/10, rbethman <rbethman at comcast.net> wrote:
> 
>> From: rbethman <rbethman at comcast.net>
>> Subject: Re: [R-390] R-1247 Nasa Receiver info
>> To: r-390 at mailman.qth.net
>> Cc: "Mack Rogers" <n4vgb at yahoo.com>, "James M. Walker"
> <chejmw at acsu.buffalo.edu>
>> Date: Thursday, February 25, 2010, 5:34 PM
>> Those 2 1/2 ton trucks set up as
>> GRC-26Ds, were "pre-positioned" in 
>> Europe.  A very large number in Germany around 30+
>> years ago.
>>
>> Send a message to WB2FCN! <James M. Walker> <chejmw at acsu.buffalo.edu>
>>
>> He's whom saw them in big numbers.  Don't know about
>> the AN/GRC-129.
>>
>> Bob - N0DGN
>>
>> On 2/25/2010 5:18 PM, Mack Rogers wrote:
>>> Strange as it may be, the AN/GRC-129 shows up on the
>> mil lists as being a modified version of AN/GRC-26D! Wonder
>> where NASA parked those deuce and a half trucks!? (big grin
>> and scratching head)
>>> SSB adapter for a T-368!? We could all go for one of
>> those!
>>> 73s
>>> N4VGB
>>> Mack Rogers
>>
> 
> 
>       
> 
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