April 1960 Popular Electronics
Table
of Contents
Wax nostalgic about and learn from the history of early electronics. See articles
from
Popular Electronics,
published October 1954 - April 1985. All copyrights are hereby acknowledged.
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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
 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)
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
 B&W photo of PAR display showing Elevation display at
top and Azimuth display on bottom. Yes, it is in dire need of alignment.
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.
See all articles from
Popular Electronics.

Posted September 25,2012
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