[Milsurplus] Collins automatic antenna coupler / tuner

[Mike Morrow]

>It is pretty much the same unit. It seems to be part of a set up to replace
>the original pieces of the ARC-38A with the 618T.

The AN/ARC-94 seems to have been the USN's replacement for their AN/ARC-38A.
The AN/ARC-94 is in fact a USN version of the 618T-2, but early installations
used the CU-991/AR which is identical to the old 180L-2, and only covered up
to 25 MHz.  The CU-1669/AR was the first 490T type of coupler (490T-1A) that
allowed operation to the 30 MHz limit of the AN/ARC-94.

The web site http://tsc-60.cellmail.com/tsc-60/other/174/index.html has some
sparse info on several variants of the 490T, excerpted below: 

--------------start excerpt------------
Antenna Couplers
 490T-1
 490T-1A  Used with the 618 series. AKA CU-1669A system. Supports 630 Watts
          and requires 115 VAC, 400 hz
 490T-2   Used with high power systems
 490T-2A
 490T-3   Used with high power systems such as the 718U-2 series
	   Rated at 1.2 KW average or peak. Required single phase 400 Hz 115 VAC
 490T-4	   Rated 1.2 KW Average or peak. Used as a line flattner
 490T-9   Used mostly with the 618T-2 series, Part number 522-4994-001,
          115 VAC/400 HZ power requirement
--------------end excerpt--------------

That mentions "high power systems" for some models (used with 718U, AN/ARC-174),
so maybe Jim's 490T-9 is rated for the 1.2 KW PEP mentioned for some other 490T
versions (even though there are no 618T models rated above 400 watts PEP, AFAIK).

Mike / KK5F