[Milsurplus] Off topic, missing pages

[Jack Antonio]

On 7/26/2018 1:48 AM, Jim Whartenby wrote:
>
>
> It seems that all 618S main chassis contain connectors and wiring that 
> mate with the SMO and a 500 kc oscillator module needed to make the 
> SMO function.  All of this is hidden under the 144 crystal L.O. module 
> and is the basis of the Navy ARC-38.

Also needed would be a servo amplifier module, to drive the frequency 
correction trimmer on the SMO assembly.
It is slightly different from the servo amp module used for the tuner 
table and PA.

I stripped a naked 618S chassis for the connectors to make test 
harnesses for my ARC-38, and it certainly
appears that the wiring was there to support the SMO and its associated 
modules.  Also the wiring was
there to support the selection of bandwidth in the IF amplifier module 
for the ARC-38.

(And if anyone needs a completely stripped 618S-1 chassis,  they are 
welcome to it).

However, I am not going to go out on a limb and say that a module swap 
is all that would be needed to
make a 618S into an RT-311/ARC-38. It *might* work, it certainly appears 
it *should* work, but there
may be other considerations.  I  have both an ARC-38 and a 618S-1, but 
don't really feel the need
to test the theory.
>
> I believe that there are only a few members of this fine list who 
> would have an interested in this bit of Cold War Radio History.
> Even fewer when it comes to the earlier ARC-21 by RCA.

If I had the room, time, and a strong back, I'd  tackle an ARC-21 project.

Jack Antonio
WA7DIA