[R-390] R-1247 Nasa Receiver FOR SALE
Les Locklear
leslocklear at cableone.net
Fri Feb 26 09:17:54 EST 2010
This gets my vote for the best informational/historical post of the year (so far).
It's great to get the facts from somebody that "was there." As someone that has been digging through the truth and fiction regarding Hammarlund Manufacturing Co., I wish that we had more people that would step forward and clear the air, so to speak.
Thanks,
Les Locklear
Gulfport, Ms.
Dx'ing since '57
http://www.hammarlund.info/
----- Original Message -----
From: John Vendely
To: Richard W. Solomon
Cc: r-390 at mailman.qth.net
Sent: Friday, February 26, 2010 7:54 AM
Subject: Re: [R-390] R-1247 Nasa Receiver FOR SALE
The R-1247 was not developed for the Apollo space program. It was
developed in 1963 as part of the AN/GRC-129, a tactical RATT van used
mainly by the Air Force. The idea was to provide frequency synthesis
facilities for the R-390A in SSB/RATT operation, solving the receiver's
long-term stability problems. Manson Labs modified stock R-390As to
accept two external frequency synthesizers which substituted for the
internal PTO, HF crystal oscillator, and 17 Mc oscillator. The
resulting system was thus phaselocked in 1 kc steps, and had much better
long-term frequency stability than the stock receiver--when it worked.
The synthesizers proved unreliable, and also degraded receiver phase
noise performance. Manson also supplied a SSB converter for the
receiver, and a SSB exciter (CV-1695/GRC-129) for use with the system's
transmitter, a modified T-368 from which the old exciter and modulator
was removed, and to which the SSB exciter and new 1 kW linear amplifier
were added.
The "R-1247 developed for Project Apollo" story appears to have
originated with a guy selling a grossly overpriced partial set of the
synthesizers several years back, and has been circulating ever since.
It's become a kind of urban legend in the surplus radio community. NASA
used many R-390As throughout its ground communications network from the
beginning of Project Mercury onwards for HF reception and as a tuneable
IF. And I can attest to the fact that they did indeed purchase a few
R-1247-style conversions from Manson Labs. However, they were
disappointingly unreliable, and were quickly removed from service.
Conversion of older equipment to SSB and frequency synthesis was a big
deal there for a while, and Manson Labs did a lot of business in this
market. They offered their upgraded R-390 systems on the commercial
market as well, usually featuring a synthesizer system which tuned in
100 cps steps (Manson Laboratories Model 299). However, they weren't
very successful. They also produced a very similar synthesizer/SSB
upgrade for the Collins AN/FRT-24 transmitter. TMC also did an R-390A
synthesizer upgrade using equipment of their design.
In all fairness, the reliability problems this equipment had were
typical of that generation of vacuum-tube frequency synthesizers. All
the synthesized gear of the time, whether purpose-built or modified,
required frequent attention to keep it going. Manson's multiloop serial
injection PLL synthesizers were audacious, state of the art designs for
their time, and by far the most physically compact. They were therefore
tweakier than most. I must say I greatly enjoy working on them though,
perhaps for this very reason, and can recommend them to anyone who's
also nuts enough to want to spend the necessary time at it...
73,
John K9WT
Malabar, FL
Richard W. Solomon wrote:
> I have to ask ...
> What mods were done to it for the Apollo Program ? I doubt
> they flew it !!
>
> 73, Dick, W1KSZ
>
>
> -----Original Message-----
>
>> From: Brian Vietri <bvietri at msn.com>
>> Sent: Feb 24, 2010 10:21 PM
>> To: R390 LIST <r-390 at mailman.qth.net>
>> Subject: [R-390] R-1247 Nasa Receiver FOR SALE
>>
>>
>> This receiver was modified for Apollo Space Program.
>> I have for sale Manson Labs R-1247 s/n 94. This unit is is great condition, works very well, very clean, has some knob paint wear, top and bottom covers and balanced antenna adapter. I have installed 600 volt Orange Caps in IF module, C603 and C606 Rebuilt, Inrush current limiter installed. (Mfg Motorola R390A s/n 1818, Manson Labs s/n 94)
>> Pictures available upon request.
>> This unit is heavy approx 75 lbs, so it will be PACKED,SHIPPED and shipped INSURED by UPS. Plz serious inquiries only.....
>> WILL NOT SHIP OUT OF USA
>>
>> Asking $1350.00 OBO + ship + ins
>>
>> Paypal Preferred
>>
>> Contact Brian bvietri at msn.com
>>
>>
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