[R-390] NASA radio

[John Vendely]

Steve.

You're exactly right, the R-1247/GRC -129 receiver was not developed for 
NASA, but for the U.S. Air Force.  Developed under contract AF 
30(635)30962 by Manson Laboratories,  GRC-129 was a frequency 
synthesized, SSB upgrade to the older AN/GRC-26D mobile, truck mounted 
HF "RATT" system used by the Army and Air Force.  The Army seems to 
have  stuck with the outdated but more reliable GRC-26D.  You're also 
correct that NASA did acquire a few R-390As equipped with Manson Labs 
synthesizers, and these were briefly used at the Bermuda Tracking 
Station, and perhaps others.  But, as you said, they were quickly 
removed from service due to problems with the synthesizers.  The "R-1247 
developed for NASA's Project Apollo" myth has been around a while, but 
it really seems to have taken off a few  years back when some character 
was working hard at peddling a set of GRC-129 synthesizers on the 
internet, and played the NASA angle like a cheap drum.  It seems the 
misinformation has been repeated so many times since then, it's simply 
become accepted as fact.  Indeed, the seller himself may not even have 
known he was spreading misinformation.  But misinformation, it was.

The GRC-129 was actually a part of the Air Force's massive effort to 
upgrade to SSB.  Although they started acquiring purpose-built 
synthesized SSB gear for the ground to air network starting around 1956, 
the Air Force had a large inventory of older HF AM systems (by then used 
mainly for teletype), and decided to convert certain eligible equipments 
to SSB.  The GRC-129 was a product of this.  Manson Labs got a lot of 
this business, and on the fixed station side, they developed a related 
system to upgrade the Air Force's AN/FRT-24  transmitters to frequency 
synthesis and SSB, the AN/FRT-24A.  Some fixed station AN/FRR-41s also 
got an upgrade similar to the GRC-129, with a version of the 
CV-1693/GRC-129 which produced a stabilized 555 kc and 100 kc for the 
CV-157s.  These are easily distinguished from the normal CV-1693 by an 
extra indicator on the upper left labeled "CV-157", which indicates the 
157s are in external phase locked mode.  These were all 1 kc step tuning 
systems, but Manson also sold a synthesizer/demodulator upgrade package 
for the R-390A, available commercially, which had an extra loop in the  
2.455-3.455 Mc synthesizer to provide 100 cps steps.

The Technical Materiel Corporation had the contract to produce the 
primary HF SSB comms gear for Project Apollo.  TMC supplied 
four-sideband, autotune versions of both the GPT-10K and GPT-40K 
transmitters (with SBG-3 exciters), and 4-sideband autotune DDR-5 
diversity receivers.  The NASA tracking ships carried six (!) GPT-10K 
10kW transmitters, and the enormous DDR-506 receiver system, essentially 
eight of the 4-sideband DDR-5 variant receivers operating as 4 
dual-diversity pairs.  These systems were installed in 1965.  These 
state of the art radios carried multiple teletype and voice channels, 
plus 1200 baud digital data which served as a backup for the 2400 baud 
satcom link between the tracking ships and Goddard.  The HF link was 
used for this purpose on more than one occasion.  In fact, due to a 
satcom failure, Apollo 11 translunar injection data was transmitted from 
Goddard to the tracking ship USNS Redstone over the 1200 baud HF system, 
which uplinked it via the Unified S-band link to the Apollo 11 spacecraft.

Though the R-1247 was not a NASA item, many stock R-390As were used by 
NASA throughout the ground network, and on the Apollo Tracking Ships 
(which carried three or four R-390As, depending on the ship).  They were 
used as general purpose HF receivers, and especially as tuneable IFs for 
downconverters.  In the latter role, they were the "back end" of the com 
receivers which received voice transmissions from Project Mercury and 
Gemini spacecraft, before the development of the Unified S-Band system 
for Project Apollo.   Project Mercury spacecraft carried a 
single-channel AM HF transceiver, and the R-390A was used to receive 
these as well.

The R-390A had a long history with NASA, and you clearly have an example 
of the genuine article there.  Are there any dates associated with the 
NASA Goddard asset tags which might indicate when it was installed?  
This might be a clue to which project it was used on.

73,

John K9WT


On 2/28/2011 4:45 AM, Steven and Michelle wrote:
> Hi all,
>           I have a standard Motorola R390a receiver, not an R-1274. It has a label above the Motorola badge with the NASA symbol on it, serial no. and property of Goddard space flight centre. It was used at the Canberra tracking station during the Apollo missions. On the top vertical edge of the readout is "Receiver No. 2". On another posting on the net (Thought it was in the Premium-rx arcives but can't find it now.) an ex NASA employee said that the R-1274 was made for the navy and NASA aquired a few but found the Manson Labs mods unreliable so they used only standard R390a's. He also said that they weren't used for tracking or to measure doppler shift. I am no expert on these radios by any means but I seen a few claims on the web that the R-1274 was built for NASA or are NASA radios. If they were, unless removed, should also have the NASA label on them one would think. Not claiming all this is right just curious. Would like to find the posting.
>                                                            Steve. vk7fxxx
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