[Milsurplus] ID this antenna matching unit?

[Ian Wilson]

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.

73, ian K3IMW