[Milsurplus] R-388/51J use

[Mike Morrow]

> ...But Collins and SSB won.
>
> Except that for some reason the AF decided to convert their old
> ARC-21 AM radios to SSB rather than buying new SSB ones. The
> result was the ARC-65.

The AM RT-128A/ARC-21 is a RCA product.  RCA made the USB upgrade as
the RT-400/ARC-65 in the very late 1950s/early 1960s.  I don't know of
any USAF Collins HF aircraft set from the 1950s except the AM 618S-1
(never assigned JAN nomenclature) and the AM 18S-4 as the RT-380/AR,
part of AN/ARC-59.  The RCA AN/ARC-65 seems to be the USAF's USB set for
the 1950s, although the first military version of the SSB Collins 618T-2
appeared as the RT-648/ARC-94 in the very late 1950s.  The Collins SSB set
that dominated SAC airborne communications in the 1960s was the 618C,
using the 18Z exciter-receiver.  The JAN nomenclature for this set is
AN/ARC-58.  The USMC adopted a ground version as the AN/TRC-75. 

The USN used the mid-1950s Collins RT-311/ARC-38 instead of the AN/ARC-21.
There is no exact commercial equivalent, though there was some little
similarity to the 618S-1/MC.  RCA, using no doubt expertise they developed
for the USAF's AN/ARC-21 to AN/ARC-65 conversion process, developed the
conversion of that AM Collins RT-311/ARC-38 to the USB RCA/Collins
RT-594/ARC-38A which were performed in the early 1960s.  Soon the Collins
618T-2 as the AN/ARC-94 appears to have been preferred...in many patrol
aircraft there was both an AN/ARC-94 *and* the older AN/ARC-38A.

So...it seems that RCA got the jump on Collins in the late 1950s for
providing the first widely deployed USB sets to both the USAF and the USN,
by the RCA conversion of the USAF RCA AN/ARC-21 to RCA AN/ARC-65 and the
USN Collins AN/ARC-38 to the RCA/Collins AN/ARC-38A.

Mike / KK5F