[Milsurplus] [MMRCG] AN/URT-23D The 10 milliwatt monster transmitter?

Francesco Ledda frledda at att.net
Sun Sep 25 15:08:32 EDT 2022 

Jim, 

Thank you for sharing your insight. Years ago, I did acquire some loose parts from the synthesizer six pack rom an SC-901. At that time, I did know that belonged to an SC-901. It looked like an early R-1051 and assumed it was. Most of the crystals and other components ended up in an R-1051B six pack in need of multiple transplants.

Best, Francesco K5URG

 

Sent from my iPad

> On Sep 25, 2022, at 13:46, Jim Whartenby via Milsurplus <milsurplus at mailman.qth.net> wrote:
> 
> 
> Nick
> 
> 
> I have an SC-901X preliminary manual that I cannot find a single date on any page.  Even the schematics have no indication of a date or revision number.  A few of the schematics appear to be one level above hand drawn, they are that crude.  Chapter 5, "Replicable Parts" is blank with the note that a list will be provided at a later date.  IMHO, this is an early manual that was packed with the initial equipment issue.
> 
> 
> Initial manuals supplied with the early shipments do not seem to have any publication date.  I have acquired several of these manuals over the years and have not found any date on any page.  If the ARC-21 can serve as an example, it first entered inventory in Feb, 1953.  The Preliminary Manual I have has no official military designation but was referred to by it's official replacement as AN 16-30ARC-21-1 and was dated as 10 February 1953 which agrees with the initial equipment shipment date.  
> 
> 
> The replacement manual to the above is know as T.O. 12R2-2ARC21-1 and is dated 15 May 1956.  This itself was revised on 15 November 1956.  I also have the "Charts & Diagrams" schematic manual used to teach students the ins and outs of the ARC-21.  It's initial issue date is 7 June 1954 with a change date of 14 March 1956 for changes 6 & 7.  
> 
> 
> It took three years and three months to go from the preliminary to official manual.  Granted that the ARC-21 had it's teething problems and was under a lot of scrutiny but the point is that it is more then possible that the time from the initial "Preliminary" to official "Military" manual can be a year or more as problems are identified and corrected.
> 
> 
> A side note, the SC-901X radios and the R-1051 receiver and it's extended family have a resemblance but the modules are not interchangeable, AFAIK.  I would assume that the only way to answer Nick's question is by looking at component date codes.  A difficult task only for the most dedicated researcher.
> 
> 
> Jim
> 
> 
> 
> Logic: Method used to arrive at the wrong conclusion, with confidence.  Murphy
> 
> 
> -----Original Message-----
> From: Nick England <navy.radio at gmail.com>
> To: Jim Whartenby <old_radio at aol.com>
> Cc: mrcg at mailman.qth.net <mrcg at mailman.qth.net>; milsurplus at mailman.qth.net <milsurplus at mailman.qth.net>
> Sent: Sun, Sep 25, 2022 9:40 am
> Subject: Re: [Milsurplus] [MMRCG] AN/URT-23D The 10 milliwatt monster transmitter?
> 
> It hasn't been clear to me which came first, the R-1051 chicken or SC-901 egg, 
> The SC-901X and SC-910A (100w amp) manuals are copyright June 1961 
> 
> but I just found the note below on Ed's page - It is from Fred Chapman W4CHT, original NAVELEX Project Engineer on the subject equipment.
> Fred was also responsible for the first Navy SSB tests with modified 75A-4 and KWS-1, later procurement of interim RCA SSB-1 transceivers, and then procuring the standard shipboard SSB transceiver, AN/URC-32. I corresponded some with Fred back when I was first getting interested in Navy radio history, but he has since passed away. Oh, how I wish I had a time machine....
> 
> Fred wrote to Ed - 
> ---------------
> The exciter was originally developed in 1961 by the U.S. Navy for the Radio
> Sets AN/WRC-1, Transmitters AN/URT-23( )  and AN/URT-24 .. it is the
> exciter T-827( ) /URC unit of these equipment's. USAF purchased units
> and renomenclatured them and in some silos they were painted black for
> some reason. Developed and originally produced by General Dynamics,
> Rochester NY.
> The AN/URT-23( ) is still in use today!!!!
> Fred Chapman W4CHT
> Original NAVELEX Project Engineer for the above equipments)
> -------------------------------
> 
> 
> Nick England K4NYW
> www.navy-radio.com
> 
> 
> On Sun, Sep 25, 2022 at 10:08 AM Jim Whartenby via Milsurplus <milsurplus at mailman.qth.net> wrote:
> General Dynamics bought Stromberg-Carlson in 1955 so S-C was a subsidiary of GD when the SC-900 series was developed, if I understand the history correctly.
> 
> Here is an email I saved years ago:
> [R-1051] SC-901
> 
> Geoff Fors geoff at wb6nvh.com 
> Mon Feb 1 19:51:58 EST 2010
> SC-901 and the 900 series as a whole were the prototypes designed around1961 by Stromberg Carlson.  
> They were typically installed in ICBM silos and you will see them in some of the photo collections on the web.  
> For example, that silo south of Tucson, Arizona, now a museum, still has them in place. 
> Presumably SC- means Stromberg Carlson.
> Geoff
> 
> 
> Not to be a troublemaker, but going back up a ways on the previous page, Collins was not involved in the R-1051. It was a Stromberg Carlson design made initially for ICBM missile silos and carried SC-900 and SC-901 designations. Later, General Dynamics took over and the R-1051's are theirs, built usually by Bendix as a contractor. There are some NATO ones built by Elmer in Italy. 
> 
> The 1051 was not made to replace the R-390A, which was still in production almost 20 years after the 1051 was introduced, although the Navy stuck them in a bunch of positions at Skaggs Island where 390A's had been. The decade frequency dial-up system sure isn't a band cruiser but it's a great SSB receiver for fixed channel point-to-point use. Which is what the military used it for. They are fixed mainly by module swapping on board ship, but at the depot level, repairs to modules are somewhat of a nightmare. And they weigh almost 100 pounds.
> WB6NVH 
> 
> Jim
> 
> Logic: Method used to arrive at the wrong conclusion, with confidence.  Murphy
> 
> 
> -----Original Message-----
> From: Francesco Ledda <frledda at att.net>
> To: MMRCG at groups.io
> Cc: mrcg at mailman.qth.net; milsurplus at mailman.qth.net
> Sent: Sun, Sep 25, 2022 8:44 am
> Subject: Re: [Milsurplus] [MMRCG] AN/URT-23D The 10 milliwatt monster transmitter?
> 
> Fair radio does have a couple of SC-901s. The last time I was there (last may), they appeared clean, but without their 8295s.
> 
> How did the SC-501 become the R-1051?
> 
> Best, Francesco K5URG
> 
> Sent from my iPad
> 
>> On Sep 25, 2022, at 08:07, Nick K4NYW <navy.radio at gmail.com> wrote:
>> 
>> 
>> Correct - the AN/URT-23 series was US Navy equipment.
>> Ed is confusing it with the USAF's General Dynamics (Stromberg-Carlson) SC-908 amp that went with his SC-901 receiver-exciter. These SC units were evidently predecessors to the R-1051, T-827, RT-618, URT-23, family
>> 
>> I have just begun a page on the SC-series at
>> https://www.navy-radio.com/xmtrs/sc-radio.htm
>> 
>> Nick England K4NYW
>> www.navy-radio.com
>> 
>> 
>> On Sun, Sep 25, 2022 at 8:50 AM Francesco Ledda <frledda at att.net> wrote:
>> The silo south of Tucson does not and did not have an URT-23. 
>> 
>> 
>>> On Sep 24, 2022, at 21:40, ED SHARPE via Milsurplus <milsurplus at mailman.qth.net> wrote:
>>> 
>>> I think we have RX/exciter Nick.... a rig was used in Titan silos for hf
>>> .have RX/exciter would love to have rest for or display at SMECC MUSEUM PROJECT in AZ...
>>> THERE IS A WHOLE USAF USED VERSION OF THIS TYPE OF GEAR IG I AM NOT MISTAKEN IN TNE TITAN SILO SOUTH OF TUCSON AZ
>>> HELP....
>>> ANY IDEAS
>>> NICK???? ( and others with ideas chip in too! Please!)
>>> 
>>> Ed#           SMECC MUSEUM 
>>> 
>>> Sent from the all new AOL app for Android
>>> 
>>> On Sat, Sep 24, 2022 at 2:45 PM, Nick England
>>> <navy.radio at gmail.com> wrote:
>>> Look at the ability of the URT-23D and later models to transmit at only 0,01 watt up to 1KW. 
>>> https://www.navy-radio.com/xmtr-shiphtm#urt23 
>>> 
>>> I presume this is for "Limited Range Intercept (LRI)" but I don't know how this works in operation? Manually or Automagically?
>>> ===========
>>> Link-11 - HF is used to establish a net when the range between units in the net is from 25 to 300 nm. For ranges of less than 25 nm, HF Limited Range Intercept (LRI) can be used
>>> ===========
>>> Nick England K4NYW
>>> www.navy-radio.com
>>> 
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