[ARC5] Is guess this for an RU?

[Mike Morrow]

Wayne wrote:

>Reference item 230628177737

The auction dose not tell you what frequencies are covered by this dual
coil set, but:
Range Q is 530 to 830 kHz, and
Range F is 2040 to 3000 kHz.

Why the odd band 530 to 830 kHz?  That was to enable the receiver to
switch from the MF/HF communications mode to the ZB/YE homing system mode
without swapping coils.  The output of the ZB homing adapter was in that
range of broadcast band frequencies.

The RU-18 was a liaison receiver that always had a radio operator nearby,
one who wouldn't be normally interested in ZB/YE homing activities.  But
the same coil set was part of the RU-16/GF-11 and RU-17/GF-12 command sets,
where the receiver was remote tuned and normally not accessible to the pilot
for coil swaps.  A dual-band coil set like that shown in the auction, remotely
switched through a spline, allowed the RU-16/17 to provide communications
and homing service.  Of course, there were likely very few RU-16/GF-11
aircraft installations, and not all that many RU-17/GF-12 installations
either.

> Interesting to note that the coil cans look so much like the ones in a 274-N.

I guess we all see different things.  I see almost no similarities between
RU coil sets and those used by ARA, SCR-274-N, and AN/ARC-5 receivers.

Mike / KK5F