Help me out here. What sort of a 'balun' or what sort of 'coax' will match
such a device to a 50 to 75 ohm unbalanced output of a usual ARS
transmitter?

Since the Texas TWIT has me blocked, I am addressing this to you Bruce.

Dan/W4NTI

Well I dont know Dan, maybe we could use a Getter to feed it, it might match
it.