[Milsurplus] SCS-51

[Mike Morrow]

Michael wrote:

>the SCS-51 didn't come into service under that designation until 1945.

The SCS-51, AFAIK, refers to the complete ILS system, both the stuff on
the ground and the stuff flying.

>From what I've read, it was called the RC-103

The RC-103-A was *only* the VHF localizer receiver, and it was deployed before
the glide-slope system was available.  I have an early RC-103 manual that
simply shows the BC-733 receiver output being sent only to the horizontal
travel needle on the I-101 indicator.  The vertical travel needle is 
shown as disconnected and for later use.  The BC-732 control box controlled
only the BC-733, which was a six-channel set.

Before war's end, the R-89/ARN-5A three-channel UHF glide slope receiver
was available to input to the vertical travel needle on the I-101.  The
existing BC-732 control was now used to select the which of the three
glide slope channels to use, in addition to which of the six localizer
channels to use.

Except for channel assignments, it's the same ILS used today.  Amazing!
The SCS-51 is a far better ILS than the one that the USN tried to use, the
old pre-war model ZA and ZA-1 (Air-Track) ILS.  I believe the USN abandoned
the ZA well before war's end.  Good thing!

Mike / KK5F