[Milsurplus] Re:ARC 65 and ARC 21 control heads, a rare exception

[antqradio at juno.com]

Don't quote me but I'm under the impression that ARC-21 operates without
400 cycle power, the auto tune servos are DC powered.  The TRC-75 needs
an inverter to provide the required 3 phase 400 cycle power, which kind
of levels the weight issue a bit.  And then, the case of the ARC-21 kind
of makes it bullet proof!

What I like most about the ARC-21 is that I believe it is the first
military radio to use a mechanical filter.  I would like one just for
that reason, heavy beast or not. 8^)  Likewise, the first receiver to use
a mechanical filter is, I believe, the SRR-11, 12, 13 family.  Go RCA!

The updating of the AM only ARC-21 to the USB ARC-65 is still a
modification while the ARC-58 / TRC-75 and all of the other systems that
used the same circuit topology like the KWT-6, 50E-6 URC-32 (and I am
sure there are others) were both AM and ISB compatible units.  That is
most likely the reason the ARC-21 / ARC-65 lost out to the ARC-58.

And then there is the Collins contemporary to the ARC-21, the ARC-38. 
Didn't RCA do the upgrade to ARC-38A?

Regards,
Jim

snip
> The AN/ARC-58 has higher rated PEP output than the 
> AN/ARC-65, and required no separate external power units.  The 
> performance difference must have been in the receivers, as you 
> state.  But the AN/ARC-58 must have been a good enough system 
> overall, since the USMC adapted the design as the AN/TRC-75.
> 
> I'm fascinated most by the RT-128A/ARC-21, but I'll never own one 
> just due to the great weight of the RT unit.
> 
>