[R-390] R-1247 Nasa Receiver info

Thu Feb 25 17:18:46 EST 2010

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 

--- On Thu, 2/25/10, Steve Toth <stoth47 at yahoo.com> wrote:

> From: Steve Toth <stoth47 at yahoo.com>
> Subject: Re: [R-390] R-1247 Nasa Receiver info
> To: r-390 at mailman.qth.net
> Date: Thursday, February 25, 2010, 5:00 PM
> 
> I have one of these.  It's an R390A with mods for external
> connection to two high stability frequency oscillators, one
> was used for Megahertz and one was used for Kilocycles (not
> included and mostly unobtanium and very expensive IF you can
> find them - although I seem to remember from a previous
> thread that someone here on the list has a set of the
> oscillators).  No changes in internal components from a
> standard R390A except the modified PTO and plug in crystal
> oven crystal can - it still uses the interchangeable power
> supply, IF, RF and audio decks but NOT the standard PTO. 
> Alignment and calibration is the same as a standard R390A.
>  
> FWIW:
> Pro:  It is unique and has a certain amount of "cool"
> factor as being an unusual version of the R390A.  You also
> get bragging rights to owning an R390A "that was modified to
> be used in the Apollo space program".  A genuinie R1247
> will have a couple easily seen mods: the three connector
> plate mounted on the upper rear panel with three jacks
> labeled "J1A, 17Mhz input", "J2A, Synth Input" and "J3A,
> 9-17Mhz" input.  You will also find a mod to the PTO (two
> mini BNC connectors just below Z702 with input cables) and
> Mod 1 labelled on the corner of the audio deck closest to
> the PTO.
>  
> Con (from a strictly practical standpoint only): The mod
> inserts relays into the oscillator signal paths.  It just
> adds one more minor thing (dirty relay contacts over time)
> to go wrong and degrade receiver performance.  It's still
> an R390A and is a great receiver, its uniqueness just adds
> one more minor aspect to its ongoing maintenance.
>  
>  
> More Info:
>  
> R-1247/GRC-129
> 
> The radio receiver R-1247/GRC-129, HF, 500 Kc to 32 Mc, is
> a high stability version of R-390A/URR using external
> ultra-high-stability oscillators. Used by NASA for the
> Apollo program and modified from the R-390A by Manson Labs.
> 
> Contract info: Manson Labs, contract AF30(635)30962 ,Part
> No 224-0A2
> 
> Additional info per Tom, N5OFF:
> " All the Oscillator outputs were in series through sets of
> 2 DPDT relays that
> appeared to allow the R390A to use its own Oscillators,
> Import external oscillator
> signals, or export its internal oscillators to a set of BNC
> jacks on the rear panel.
> 
> By all the oscillators I mean PTO, 17Mcy XTAL, and the 1st
> conversion xtal. These 
> relays required external power via a small connector
> labeled CONTROL.
> 
> The relays were Mil Spec commercial units mounted on well
> machined casts that
> fit into the OSC tube sockets on the PTO and Heterodyne
> osc. and the one for 17mhz xtal plugged into the socket for
> crystal oven. There were 2 small dia. color coded coax 
> cables going to each relay.  The R390a worked normally
> with no connections to any of 
> the connectors."
>  
> Additional info per WF2U Landrum, SC
> This equipment was part of the AN/GRC-129 system which had
> 2 R-1247 receivers for dual diversity.  The 2 receivers had
> the CV-1694/GRC-129 Single Sideband Converter, (Manson Labs)
> connected to them, The CV-1693/GRC-129 is the 1 MHz step
> synthesizer and the O-1203/GRC-129 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. 
>  
> Both synthesizers and the converter were built by Manson
> Labs, but the synthesizers were also made under contract by
> Hallicrafters, in their last throes of death.
>  
> The system transmitter was the modified (for sideband)
> T-368, under the nomenclature T-946/GRC-129, driven by the
> O-1555/URC synthesizer. 
>  
> -- Steve 
> 
> 
> 
> 
> 
> 
> Woodinville, WA
> 
>  
> 
> --- 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 FOR SALE
> To: r-390 at mailman.qth.net
> Date: Thursday, February 25, 2010, 11:34 AM
> 
> 
> Mack,
> 
> It will only go for what someone is willing to pay.
> 
> The add-ons by Manson Labs are useless!  There is no way
> of getting the 
> external equipment that is designed to connect to the
> modifications!  
> (Another BIG Smile!)
> 
> I won't belittle someone's offerings or desired price!
> 
> It belongs to him, he has every right in the world to place
> a price on 
> it that HE feels is proper.
> 
> Folks like you and I won't be making offers.  (ROTFLMAO!)
> 
> Bob - N0DGN
> 
> On 2/25/2010 1:58 PM, Mack Rogers wrote:
> > Unless you own some of the external auxillary gear to
> go along with a R-1247 rcvr, it's just an R-390A with more
> connectors on the back. (big smile)
> >
> > An unusual collectors item, yes, but still just a
> R-390A.
> >
> > N4VGB
> > Mack Rogers
> >
> >    
> >> 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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