[ARC5] Early Helicopter Radios (and some later ones)

[Mike Morrow]

> At one time, at the Air and Space Museum in downtown DC they had an 
> excellent photo of one of those same helicopters take from head on.
> You could clearly see a single 274-N transmitter and receiver
> behind the pilot, probably the most obvious radio installation 
> I have ever seen.

Immediately post-WWII, many USN primary trainer aircraft had
an MF/HF AN/ARC-5 installation...no VHF stuff.  Commonly:

R-23*/ARC-5  beacon band/tower-to-plane (including 278 kHz)
R-26/ARC-5   plane-to-plane (3105 kHz)
T-19/ARC-5   plane-to-tower, plane-to-plane (3105 kHz)

I have pictures of such an installation, and the antenna relay
is clearly a BC-442-A instead of a RE-2/ARC-5.

Also, each receiver had a pilot-tuned C-125/ARC-5 control panel.
There was no transmitter control box, since a one-transmitter
command set installation needs only the PTT on the mic as its
sole control.

> I'm left wondering where the antenna would have been fitted...

I suspect in that early helo photo, the receiver was simply a
BC-453-B beacon band unit, which wouldn't need too sophisticated
an antenna.  It's hard to identify any transmitting equipment
in the photo. 

Jumping forward only 25 years, the Vietnam-era UH-1D/H models
that carried much of the U.S. Army aviation work load had a
few more radios than what's aboard that early helo, including
on later models:

AN/ARC-51BX     UHF-AM
AN/ARC-102      MF/HF-USB  (Command aircraft only)
AN/ARC-131      VHF-FM
TSEC/KY-28      Voice encryption (NESTOR) for VHF-FM
AN/ARC-134      VHF-AM
AN/ARC-82       VHF-VOR/LOC
AN/ARC-83       LF/MF ADF
AN/APX-72       IFF

That's what develops in only 25 years between the first photo
and a 1970 combat helo.  Pretty impressive.

BTW, the HF antenna on a UH-1 is a zig-zag wire conductor running
along the port side of the tail boom.  It was auto-tuned to the
AN/ARC-102 by a CU-991/AR coupler.

Mike / KK5F