[Milsurplus] T-47/ART-13 converted to T-47A (Almost), plus AN/ART-13 Cal Books

[Mike Morrow]

At http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=200405702962
there's a pretty good condition T-47 made by Collins that appears
(judging from the nomenclature plate) to have actually been made as
a T-47 rather than being an old ATC that had just had "T-47/ART-13"
stamped or painted later somewhere near the original ATC plate.

What's more interesting is that the original USN T-47/ART-13 tag has
"T-47A" added.  Looking at the transmitter, though, the conversion
is not complete.

This unit has other T-47A qualities such as the 8Q-2 MCW-CFI unit,
the MT-263/ART-13 mount hardware, and the dynamotor control power
top-lid interlock switch, but it lacks the most important thing that
distinguishes a T-47A from the T-47:  There is NO HF VFO dial B vernier
scale.

It is that scale that allows the T-47A to be set at 1 kHz intervals
throughout its complete tuning range with cal data from the transmitter
calibration book.  The T-47 and ATC lacked this vernier, and their cal
books are much thinner, since their VFO setting data are presented only
for 5 or 10 kHz intervals.

It seems strange to me that a transmitter lacking this important
characteristic would be officially marked as a T-47A.

BTW, there was an AN/ART-13 cal data book recently offered on this list.
These are rare, plus there are at least four different varieties:

(1) USN ATC (or ATC-1) with 8Q-1 MCW-CFI (two tube) unit
(2) USN T-47/ART-13 with 8Q-1 MCW-CFI (two tube) unit
(3) USN T-47/ART-13 with 8Q-2 MCW-CFI (three tube) unit
(4) USAAF/USAF T-47A/ART-13 (Always has 8Q-2, Cal data at 1 kHz intervals)

There may also be books for the Collins 17H-2 (commercial version),
and the ATC (or ATC-1) with 8Q-2.

If you find one, unless you're lucky it likely won't the the book
that goes with your transmitter version.  Fortunately, the cal data are
very close to being the same in all versions, with the major difference
being the interval at which data are provided (T-47 vs. T-47A) and the
interval at which calibration points are provided (8Q-1 vs. 8Q-2).
Even though the cal data for the Soviet version of these transmitters
depart somewhat from the US models, even they are still in the same
ballpark. 

Manuals for the T-412/ART-13B (crystal-controlled option, CDA-T unit)
appear to show the T-412 being based on a USAF T-47A unit (with vernier
scale), but most of the T-412 units that I've seen were built on USN
ATC or T-47 units that had apparently been half converted to a 
pseudo-T-47A like the unit in this auction.

Mike / KK5F