[Milsurplus] ID this antenna matching unit?

[WA5CAB at cs.com]

Best guess if US is CU-25/ART-13 (200-600 KC).  200-600 KC.  Transmitter 
connector is much smaller than antenna one.

Of the other US liaison transmitters, GO doesn't have an external loading 
unit, one for GP is smaller than an ARA receiver, CU-26 is about the size of 
an ARA, and SCR-183/283 uses BC-306, not even vaguely cube shaped.  There 
was a Canadian set arranged similarly to the GO (three side by side units) but 
I can't recall the nomenclature and don't recall whether it had an external 
MF loading unit.

In a message dated 11/11/2012 20:44:11 PM Central Standard Time, 
ianmwilson73 at gmail.com writes: 
> This is approximately a 1-foot cube. Antenna and transmitter
> connections are on (almost) hemispherical ceramic standoffs.
> 
> Frequency range is up to about 400kc (I forget the lower range
> but I am guessing 200kc - 400kc+).
> 
> Legend says "Use 200 foot trailing wire antenna". No nomenclature
> plate. Another legend says something about tuning for plate
> current. Large meter (RF ammeter??) is missing from panel.
> 
> Internally has a large (8" tall) inductor with numerous taps, and
> a gorgeous variometer variable coupling device (also large).
> 
> It may still be possible to rescue this unit (I didn't adopt it because
> I am seriously running out of space, and the meter is missing).
> Not mine - no financial interest on my part.

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