[Milsurplus] What is a C-400A/APW-11?

[Mike Morrow]

Michael wrote:

> Found this in the garage; forgot I had it.  Looks like 1950s ECM or 
> RADAR stuff.

I believe that the AN/APW-11 is a USAF airborne radar beacon used from
the early mid-1950s to the early 1960s.

I've never found much information on the AN/ARW-11.  The only part of
the system that I have is the RT-122B/APW-11.  There is a later model
called the RT-447/APW-11 that I've seen on ebay several times (it never
sells due an unrealistic reserve or minimum the seller always sets).  I've
seen several RT-122s at Dayton (typically for about $5).  It's an interesting
set that will fit in a SCR-274-N FT-234-A single transmitter mount if the
rear connector on the mount is rotated 180 degrees and holes are drilled
to accomodate the RT-122 rear chassis guide pins.  I don't know what
actual mount was used.

The C-400 is a tone coder unit.  The earliest aircraft manuals that I've
seen that reference the AN/APW-11 are those of the B-57 and F-84.  Apparently
this is a S-band radar tracking beacon that communicated to a ground tracking
radar upon interrogation the heading, speed, and altitude of the aircraft using
audio tones (hence the C-400), all intended to help ground control get the
aircraft in the proper location for weapons delivery.  One can find many
references to the AN/APW-11 being installed on manned and unmanned experimental
aircraft and missiles to enhance ground tracking.

I hope someone will join in this exchange who has better understanding of
the details of use and function of the AN/APW-11 than I do, and can correct
inaccuracies.

Mike / KK5F