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SECTION 5
ANTENNA ALIGNMENT AND TUNING
5.1
ELEVATION ADJUSTMENT
1.
Prior to setting the rough elevation angle, make sure that the threaded portion of
the elevation rod is centered in the elevation block. Place an inclinometer on the
hub as shown in figure 12.
2.
The rough elevation angle is set by raising up on the lower edge of the reflector
and removing the 1/2" bolt through the two struts of the elevation adjustment rod.
Continue lifting up on the reflector until the desired angle is read on the
inclinometer. Place the 1/2" bolt through the hole in the strut that is closest to this
angle. Adjust the 3/4" nuts at the elevation block until the exact angle is read on
the inclinometer.
5.2
AZIMUTH ADJUSTMENT
1.
Make sure that all the 1/2" bolts in the canister are loose. Sweep the antenna in
the azimuth until the desired signal is found. If the desired signal is not found, it
may be necessary to alter the elevation angle slightly. Rotate in azimuth slowly
until loss of signal is observed . Rotate the antenna in the opposite direction until
the signal strengthens, and then weakens again. Set the azimuth between these
two points and snug the canister.
5.3
FINE TUNING
1.
After setting the azimuth, return to the elevation adjustment and fine tune in the
same way, splitting the difference between the two points where loss of signal is
first observed. Check the azimuth adjustment once more, then tighten all canister
and elevation rod hardware.
5.4
REFLECTOR FINE ADJUSTMENT
1.
As discussed in section 2, a level surface is necessary for assembly of the reflec-
tor. If a level surface is not available, the reflector may be checked for accuracy
by use of strings across the aperture.
2.
Use thin cord across the reflector diameter from rim to rim, at four places. One
end of each string should be taped to the rim just to one side of the seam
between two petals. The other end should be fastened 180 degrees opposite. All
four strings should lightly touch where they cross at the center. The distance from
center of the reflector (hub to plate) to the strings should be 23.22" for the 3.4M
and 24" for the 3.7M.
3.4M & 3.7M Az/El TRUSS MOUNT
30
4096-225
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