[R-1051] activity

[David Wise]

My R-1051 came to me with a troubled frequency standard module.  It oscillated fine, but the oven was inoperative.  The PTC thermistor was open.  Rather than search for an exact or similar replacement (PTC's are rare today), I modified the circuit to use a cheap and readily available NTC part.  I used a storage scope (Tek 7313) to trace the oven controller output as I tuned the loop gain for fast response while damping out oscillation.  My writeup should be in the group archive.

Best Regards,
Dave Wise
SWL in Hillsboro, Oregon
________________________________________
From: R-1051 <r-1051-bounces at mailman.qth.net> on behalf of Guido Santacana <gsantacanav at gmail.com>
Sent: Tuesday, March 07, 2017 2:34 PM
To: R-1051 Discussion Group
Subject: Re: [R-1051] activity

Well, the R1051 was a hybrid of the 60s and apparently even used in the
first nuclear submarine Nautilus. My son visited the venerable sub and sent
me an image of the radio room showing the R1051. Mine has been in the shack
for 15 years requiring only a minor bridge rectifier repair of the 28VDC
supply. It gets a weekly exercise and works well except for the 28VDC
lamps. Did General Dynamics ever came up with a follow up of this set?

Best 73s

Guido

G. Santacana KP4FAR

On Tue, Mar 7, 2017 at 1:00 PM, Ray Fantini <RAFANTINI at salisbury.edu> wrote:

> Being that no one else is writing anything thought I would take the
> opportunity to use up some bandwidth and talk about the wonder of General
> Dynamics and the whole family of radios that includes the R-1051, RT-618,
> T- 827(URT-23) and there evil ground base cousins the AN/GRC-106 I put all
> these radios in the same class being they all are hybrids,  all of them use
> a couple tubes in the rotating turret and rely on the turret technology to
> provide the necessary image rejection and unwanted spurious products that
> first generation synthesized sets produced. As far as I know that’s the
> majority of 1 MHz rotary turrets sets that I know of. I have seen similar
> ideas in ITT Mackey and Sunair but they are a bit newer being all solid
> state and rely on tons of miniature reed relays to select the 1MHz band
> pass filters and don’t use the turret. The older and more costly turret
> wins out in my mind and for that reason those radios are somewhat special
> to me. Just as a side note let me point out the Harris URC-94 or RF-280
> that’s something like all the Sunair and other stuff but instead of a bunch
> of bandpass filters and relays they have a signal section with a manual
> tuned bandpass filter that takes the place of the turret or the filter
> board with all its relays. Great stuff, think the Big heavy Harris is one
> my favorite sets just because the way they got around this spurious and
> image problem but wonder how many Navy personal were befuddled by the
> process of having to push “TUNE” and peak for maximum reading?
> The sixties, seventies and eighties were truly a peak of engineering
> design and implementation of new and sometimes unique concepts, not like
> that old WW2 crap that was used in the command sets that other reflectors
> keep going on about.
> But enough about all that, is there a point to my email? Well maybe not.
> Let me say something about the 5 MHz reference oscillator assembly for the
> GRC-106 that for some unknown reason I have been seeing them fail a lot.
> For those of you following along at home that’s the 1A3 Frequency Reference
> Module. The crystal oscillator is a simple two transistor circuit but no
> matter what I do it is beyond my capability to repair one of those little
> bastards. Tried changing capacitors, transistors and everything else but
> find that if I can’t get them to oscillate they just won’t osculate no
> matter what I do. Gone so far as to gut the oscillator section and build a
> replacement oscillator or use an sealed 5 MHz time base to replace them.
> The worst thing of all is that I got a 1A3 assembly that was NOS, never
> opened and it had the same failure where the oscillator would occasionally
> not start. That’s the problem is they won’t always start but then if you
> touch the tuning capacitor or just do a reading with a meter the dam things
> start up and run again or you will do some changes and testing the assembly
> outside the radio it will work but when you get it all back together and
> after seeing it work on the bench a week or so later when you go to use the
> radio it won’t oscillate! The weird this is I have seen this on a couple
> RT-662 and RT-834 exciters-receivers but as far as I know have never had an
> issue with the Navy time base in the R-1051.
> Well that’s enough of my rant for now, let’s see if any of you other
> people can write.
>
> Ray F/KA3EKH
>
>
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