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The Loop Canyon Antenna Test Ranges are located
on top of mountain peaks for isolated
point-to-point antenna settings. With 1000 ft
drop-off in between different test sites, test
range purity is >-55 dB with dynamic ranges of
>-60 dB (dependent on frequency). There are
currently 7 multi-purpose test ranges located
around the main complex using road access,
buildings and parking areas from a
decommissioned US Army "Missile site." These
ranges vary from 2900 to 4900 ft including a
separate 1 KM range and are capable of
frequencies from 900 MHz to 18 GHz with existing
test equipment and fixtures for flexible setups
to meet various applications. An additional
longer range (10.2-mile) is available from the
Van Nuys plant using a positioner mounted on the
center tower. The ranges are surveyed for
angular and range accuracy to detect any
noticeable ground shift in order to maintain
alignment and beam angle integrity.
Nonmetallic control buildings, structures and
revetment walls are installed around the test
towers.
With 1000 ft deep valleys and multi-path RF
fences, the range has been designed to minimize
any reflections from the ground or surrounding
area. The combination of tower rigidity and low
reflection levels results in a very clean
antenna range capable of low sidelobe
measurements, accurate cross-polarization and
measuring antennas with narrow beamwidths. Both
mid and long range sites have 4th axis brackets
and positioners for additional testing and
elimination of ground based pattern errors.
The LC-1 tower uses the Scientific-Atlanta model
#55850 Positioner which can handle antenna loads
up to 30,000 lbs and is controlled with the
Scientific-Atlanta model #4180A remote control
unit. MI3000 1797 Receiver Test Station is used
to generate antenna azimuth and elevation
amplitude and phase testing.
The LC-4 tower positioner is a
Scientific-Atlanta model #55450. This positioner
can accommodate similar antennas as the 55850
located at the LC-1 test site. This positioner
is also controlled with Scientific-Atlanta
model #4180A remote control unit and MI3000 1797
Receiver Test Station.
Also available on each tower are single boom
equipment cranes to lift up to 1000 lbs at a 75
degree tilt from the drop off and assembly areas
to the topmost antenna positioners. Both LC-1
and LC-4 are installed with Condor hydraulic man
lifts. LC-1 has a 60 ft man lift and LC-4 has a
46 ft man lift to assist in the final assembly,
alignment and testing. The 4th axis additional
L-bracket at LC-1 uses a 51300A series
positioner which has an 18" and 28": bolt hole
patterns. The 4th axis L-bracket at the LC-4
site has 12" and 22" bolt hole patterns for
mounting adapters and antenna bases |
