[MRCA] Univac Aircraft Antenna Coupler

[scottjohnson1 at cox.net]

Jim Whartenby is the resident expert on these couplers, but it is P/O the ARC-65 SSB transceiver used on the B-52 and KC-135 until they were fitted with the ARC-190.  That transition happened in the 1980s, so it is likely that coupler never saw service after it was serviced. Both Jim and I have ARC-65s and ARC-21s (the AM version which was modified for SSB to become the ARC-65 in the late fifties).

Regards,
Scott W7SVJ

-----Original Message-----
From: mrca-bounces at mailman.qth.net <mrca-bounces at mailman.qth.net> On Behalf Of Michael St. Angelo via MRCA
Sent: Sunday, January 18, 2026 10:53 AM
To: mrca at mailman.qth.net; milsurplus at mailman.qth.net; MMRCG at groups.io
Subject: [MRCA] Univac Aircraft Antenna Coupler

Going through some military stuff on a snowy Sunday and found a couple of aircraft antenna couplers I got surplus years ago. They were designed by ERA and this model was built by Univac. The are an HF Coupler mounted in the vertical stabilizer of a plane such as a KC-135 to tune the probe HF antenna. They were hermetically sealed and basically consist of a rotary inductor and vacuum variable capacitor tuned via a discriminator circuit. 

I've attached a couple of pictures. The discriminator section has the cover removed. They were last services at Warner Robbins in 1965. I was told they require 28 VDC and 100 AC 400 Hz. The RF connection is made via a C connector (my favorite RF connector)

I was going to use the components in a tuner but want to get in operational in their original state. Does anyone have any documentation about the tuner or it's controller box?

Thanks in Advance,

Mike N2MS