[Milsurplus] Another Estate

[C Whitaker]

de WB2CPN                  Ol' AACS/AFCS man

Not to rankle any any one, but I spent a USAF career around
nav aids.  Here it is:  The first Ground Controlled Approach (GCA)
was the Gillfillian AN/MPN-1.  It consisted of two trailers, one was
the operating equipment, the other was the air conditioning and misc
power equipment.  A large truck, (prime mover), contained the AC
generators (diesel).  Classification up until 1946 was Confidential.

The MPN-1 was replaced by the AN/CPN-4, which could be carried in
the largest USAF transport aircraft.   It was more modern, and used a
lot of 6AK5 size tubes.  The first CPN-4 I ever saw was at Templehof
during the Berlin Airlift.  One positive change was that the CPN-4 final
controller had both Az-El scans on the same scope, and they were read
directly off the face of the tube.  The PPI (search) antenna for MPN-1
and CPN-4 went through a number of improvements, all of which looked
different.

In order for aircraft to land in either direction, (when justifiable), 
the CPN-4
could be placed on a "turntable" which was fabricated locally.  It took 
about
45 minutes to push the whole thing 180 degrees around, and to line up the
scopes.  Some rich kids had separate CPN-4's at each end of the runway.

The AN/FPN-16 was a trimmed down transistorized clone of the CPN-4,
except its scopes were remoted to a Radar Approach Control (RAPCON),
and it didn't have a PPI (Search) feature.  Ergo, it was a lot smaller.  
The
AN/CPN-18, or the AN/CPS-5, was used for the search radar function, and
was usually located on a nearby hill or tall building.  Everything being 
remoted
into a  RAPCON facility, the AN/FSA-4 communication consoles tied everything
together.

The FPN-16 sat about 5' high on a metal framework.  The Standard Facility
Equipment List (SFEL) for the FPN-16 included an optional turntable.  That
turntable wasn't built locally, and usually worked. 

End of Trivia     73      Clete      (Sorry 'bout rambling on.)