[MRCA] Calibration book

[Mike Morrow]

William C Taylor wrote:

> I'm trying to find a calibration book for my transmitter. It's a
> T-47/ART-13 with O-16 Oscillator and 8Q-1 MCW-CFI unit.>>   

Jeep wrote:

>Looks like there's one on Ebay, now.


Well...no, there's not one for the transmitter described.

The auction at:  

http://cgi.ebay.com/ART-13-transmitter-CALIBRATION-BOOK-/220663938167

is the cal book for an AN/ART-13A (T-47A/ART-13 and O-17/ART-13A).
These use the 8Q-2 MCW-CFI.

This calibration book will differ from the correct cal book as
follows:

(1) This book is more than twice the thickness of the cal book for
the AN/ART-13 (T-47/ART-13, not T-47A), because it has cal data at
1 KC intervals throughout the tuning range.  This is because the
vernier scale above VFO dial B on the T-47A allows greater precision
in setting the VFO than does dial B on the T-47.  The T-47 cal
book present cal data intervals ONLY at 5 KC in the lower bands, and
10 KC in the upper bands.
(2) The cal book present cal data for the O-17/ART-13A LF/MF oscillator,
which is 200 to 600 KC.  It will not have cal data for the full range
of the O-16/ART-13 (200 to 1500 KC).
(3) All T-47A units normally have the 8Q-2 MCW-CFI sub-assembly.  Thus,
calibration points shown for the T-47A will generally NOT agree with
cal points appropriate to a unit with the earlier 8Q-1 MCW-CFI unit.

The auction cal book is interesting since it is a US Navy issue book.
Most such transmitters used by the USN were T-47 units.  This does
indicate there was enough use of the USAAF's improved T-47A model in
the USN by the late 1940s for a specific cal book to be issued by naval
authorities.  I knew the USN later used the CU-32/ART-13A LF/MF external
tank coil, and DY-17 and DY-17A/ART-13A dynamotors, so this book verifies
that the T-47A also saw later Navy use, in addition to their T-47.

The $60 auction start price for a poor condition cal book is, IMHO,
a little high.  It's in Australia.

Mike / KK5F