[ARC5] Nomenclature Taxonomy - AN/ART-13B

[WA5CAB at cs.com]

Mike,

I'm sorry, but the bama copy of T.O. 12R2-2ART13-1 does not agree with my 
file copy (source document).  I acquired the later changes individually (not 
as part of the base AN 08-30ART13-3, AN 16-30ART13-3 or T.O. 12R2-2ART13-1) 
and the 27 August 1952 revision pages were low quality, only slightly better 
than the bama standard.  But the lower photograph on Page 1-2A is captioned 
"Figure 1-2A.  Radio Transmitter T-412/ART-13B -- Front View".  It shows a 
front view of T-412/ART13B including the MF range switch and nameplate.  How 
this came about I don't know, but the quality of the copy is so poor it had 
to have been done at a time when the technology to doctor it didn't yet 
exist.  And I certainly didn't doctor it  The photograph appears to be the same 
as the one on Page 1-4 of T.O. 12R2-2ART13-2 dated 30 March 1956 Revised 28 
June 1958.  Perhaps the Air Force decided to reduce the confusion factor 
and make all transmitters fitted with the CDA-T T-412's match the system 
schematic in the latter manual.   Could be an explanation for the chintzy T-412 
nameplates.  Hurry-up job.  Give me time to sleep on it and I can probably 
remember earlier examples of similar cases.  I know at least one SCR-522/542 
Change package came out in two different versions.

Part of the problem may be that although the large Operator's Manual 
followed one revision path covering all models and variants straight through from 
17 September 1944 to 26 September 1968, the maintenance manuals didn't.  The 
AN/ART-13 Maintenance Manual went from 26 January 1945 up through 15 July 
1954.  The AN/ART-13A manual started new from scratch as AN 16-30ART13-4 08 
March 1949 and was revised up through 15 September 1954.  It was rewritten 
and reissued as T.O. 12R2-2ART13-2 30 March 1956 covering AN/ART-13A and 
AN/ART-13B and revised once, 25 June 1958.

The CDA-T was designed by Pan American Airways Engineering Department in 
1948 and built for them by Gable Engineering probably in 1949 and maybe 1950.  
Judging by engraved front panel plates I've seen, one or two other 
contractors also either built or installed the kits using Gable documentation but I 
can't say whether they were working for PanAm or USAF.  All that I know for 
certain is that I acquired in the early or mid 90's (along with a lot of 
other AN/ART-13 and BC-348 parts) three complete conversion kits from Sid 
Arotsky (Aircraft Radio Industries, Inc.) that included several front panel 
plates, not all the same.  Sid's stuff probably came from USAF, not PanAm.  So it 
wouldn't surprise me if USAF bought some kits in the early 50's using 
contingency funds and installed them and only later formalized the mods as 
T-412/ART-13B and straightened out the paperwork and possibly the hardware.

The Gable documents state that most mods were made to 52286's and T-47's.  
But include instructions for modifying the LOCAL-REMOTE switch supplied in 
the kits for use in T-47A and say that modified switch index plates are also 
available from them..

In a message dated 6/25/2011 3:52:58 PM Central Daylight Time, 
kk5f at earthlink.net writes: 
> http://bama.edebris.com/manuals/military/an-art13/
> 
> The -1 manual there does not have a picture of the T-412, nor any explict
> reference to "T-412".  
> 
> There is a picture of the T-47A with CDA-T and no EXTENDED LOW FREQUENCY
> switch on page 1-2A.  There is text on page 1-1 that defines this as the
> AN/ART-13B.  Operation between 1670 to 2000 kHz is not possible.  These
> pages were revised on 27AUG52 to add these details.  This sets a date of
> not later than 1952 for the first early AN/ART-13B systems.  No new
> nomenclature was applied.
> 

Robert & Susan Downs - Houston
wa5cab dot com (Web Store)
MVPA 9480