[Milsurplus] Signal Corps Info Golden Nuggets.

[Robert W. Downs]

Hue,

The ATC and ATC-1 (2nd contract), which became AN/ART-13 by the simple
expedient of changing (or in some cases installing) nameplates, covered
2,000-18,100 KC with the 10-channel autotune system and 200-1500 KC with
the plug-in LF/MF oscillator (no separate nomenclature in the ATC,-1;
O-17/ART-13 in the AN/ART-13).  The AN/ART-13 system included an
MX-128/ART-13 blanking panel and filament resistor that could replace the=

O-16, but I can't find any such unit in the ATC manual that I have dated =
01
February 1944.  So it would seem to follow that all ATC's and all
(converted) early T-47/ART-13's had the 200-1500 KC capability.  The
AN/ART-13A included the O-17/ART-13A which only cover 200-600 KC.  None o=
f
the various manuals on the AN/ART-13(*) that I have give any clue as to h=
ow
many T-47 or T-47A's were supplied with the LF/MF or LF oscillators. =

However, the last model, AN/ART-13B (T-412/ART-13B) included the CDA-T
crystal oscillator more or less permanently installed in place of the O-1=
6,
O-17 or MX-128.  Besides HF, the CDA-T also cover 300-500 KC (4 channels =
in
3 sockets), with most of the few that I've had coming with a 500 KC cryst=
al
plus some of them had one or two other crystals below 500 KC.  According =
to
documentation that I have, there was also an HF only variant but the 10 o=
r
so that I have seen all had the LF capability.

All of the more or less complete CDA-T conversion kits that I had except
for a few bits and pieces went to three current list members, and I think=

that I included a proportional share of the crystals to each.  So if anyo=
ne
is interested in what those frequencies below 500 KC were, perhaps they
(the three) will post the frequencies here.  =


But keep in mind that the AN/ART-13B didn't appear until after the Korean=

War, at least according to the dates on the T.O. revisions.  The CDA-T
itself was done a little earlier, for Pan American Airways, but still pos=
t
WW-II.  The earliest date that I can make out on the conversion wiring
diagram is 8/20/48.

>My turn to forget, but wasn't this tuner covering LF and MF both.
Didn't the ATC/ ART-13 only tune 1.5-18.5 without it? Maybe i'm wrong.
<

73
Robert Downs
<RWDowns_WA5CAB@compuserve.com>
Houston