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StarBand
®
Field Service & Maintenance Bulletins
15
minimum criteria or is marginal. This procedure can also be used with the cross-pol
procedure, described next, to help correct the antenna alignment of an existing
installation, which has been identified by StarBand
®
as having excessive cross-pol.
Substep 1
Call CVACS while at the antenna, so that adjustments can be made if
needed. Use the CVACS “
Antenna Alignment
” submenu, to confirm the
antenna co-pol and cross-pol alignment criteria have been met. If both the
co- and cross-pol criteria are met, you can proceed with Step 10.
Substep 2
If not, verify the polarizer has the “
H
” or “
V
” (depending on your satellite
assignment) pointed to “
0
” on the polarizer scale.
Substep 3
While listening to the CVACS co-pol readings from the “
Antenna
Alignment
” submenu, make small adjustments first to the elevation angle,
until CVACS reports a peak value. Then make small adjustments to the
azimuth angle, until CVACS reports a peak value.
Substep 4
Again use the CVACS “
Antenna Alignment
” submenu to confirm the
antenna co-pol/cross-pol alignment criteria have been met. If the co-pol
passes but the cross-pol does not, proceed to the
Antenna Cross-pol
Reduction Procedure
, below. If both criteria are met, proceed with Step 10.
Antenna Cross-pol Reduction Procedure:
If the cross-pol signal is still above the specified minimum, take the following action:
While listening to the CVACS cross-pol readings from the “
Antenna Alignment
”
submenu, make small adjustments to the skew angle until CVACS reports a minimum
value. At this point the antenna should be properly aligned and all bolts can be
tightened to the specified torque, but be careful not to make unwanted changes to the
antenna position. If the alignment criteria have been met, proceed with Step 10.
Important
Almost all cross-pol problems can be avoided or resolved if the mast is
plumb, the polarizer points to “H” or “V” according to your satellite assignment, skew
is set to the indicated angle, and the elevation and azimuth angles have been peaked on
the receive signal. This last item is very important! If the elevation and azimuth angles
are not peaked on the receive signal, the cross-pol signal will not be minimized.
Caution
The StarBand® satellite modem must be online and undisturbed for at least
five minutes, before completing the installation as described below.
Step 10
With the antenna peaked and bolts tightened to the specified torque, complete the
commissioning process by calling CVACS to obtain the confirmation number,
using the “
Confirmation Number
” submenu. CVACS measures the co-pol and
cross-pol values again, to verify the antenna is within the specified limits.
StarBand
®
maintains a record of the co-pol and cross-pol measured for each
VSAT. CVACS does not accept a site with out-of-specification co-pol or cross-pol
readings. All properly installed sites will exceed these specifications.
