This is cool. I saw a U.S.
Air Force recruitment advertisement in a 1960 edition of Popular Electronics pitching careers as radar operators (air traffic control)
and technicians (maintenance). The picture has the dual-display glide path and elevation sweeps from the MPN/13/14
radar system that I worked on in the late 1970s - early 1980s. A photo I took circa 1980 of our unit based at Robins
AFB, Georgia, is shown below. The precision approach radar (PAR) operated at x-band (10 GHz) with an operational
range of 10 nautical miles. The
of Contents]People old and young enjoy waxing nostalgic about and learning some of the history of early electronics.
Popular Electronics was published from October 1954 through April 1985. As time permits, I will be glad to scan articles
for you. All copyrights (if any) are hereby acknowledged.
azimuth and elevation antennas were mechanically swept with motors that changed the geometry of a waveguide having
dipole stubs along its length. The entire PAR system was built with vacuum tubes and chassis using point-to-point
wiring. Sweep patterns on the CRT were aligned using an iterative procedure to adjust
Equipment Trailer nearest in photo, Maintenance trailer inline and connected to the rear, RAPCON separate and to
the right. ASR & IFF antennas toward center of trailer, PAR Elevation antenna nearest. (circa 1979-82)
linearity, x-y position, outline, size, course line and glide slope centerlines, etc. It could be quite frustrating
until you got the hang of it. Unlike the airport surveillance radar (ASR) portion of the system which was used for
flight path vectoring and aircraft separation while at cruising and transition altitudes, the PAR was used to guide
aircraft down nearly to the ground in "blind landings." Air traffic controllers were in constant contact with the
pilots giving them corrections as needed to stay centered on the line. I don't recall the decision height for USAF
airplanes, but for civilian aviation in Instrument Flight Rules (IFR), it can be as low as 50 feet - that is not much
time to stop a landing approach and transition to a missed approach maneuver.
B&W photo of PAR display showing Elevation display at top and Azimuth display on bottom. Yes, it is in dire
need of alignment.
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