DAC-2202 Antenna Control Unit
Operation
2-15
search up along the polarization angle SWEEP INCR degrees, step two Search Increments to the left, search
down, etc expanding out in the search pattern until Search Limit is reached. When the end of the search
pattern is reached, the ACU will retarget the antenna to the calculated Azimuth and Elevation point.
If the desired signal is found (AND network lock is achieved in the satellite modem) at this position, or
anywhere within the search pattern, the ACU will terminate search and go into Tracking mode. If the desired
signal is not found the ACU will wait SEARCH DELAY, then target the antenna to start point shown in the
graphic above and begin the search pattern again. This cycle will repeat until the desired satellite signal is
found or the operator intervenes.
2.1.3.
No Gyro Search Pattern
If the ship does not have a gyro compass to use as a heading input to the Antenna Control Unit, you may
manually key in the actual heading of the vessel and then re-target the desired satellite, every time you need
to re-target a satellite, or configure the ACU to do a “No Gyro Search Pattern”.
You configure the ACU to use this pattern by using the following settings:
SEARCH INC
- set to the default value for the frequency band that your antenna model is currently
being used for (typically 15 counts for Ku-Band antennas and 30 for C-Band antennas)).
SEARCH LIMIT
– leave this set to the default value (typically 100 counts for Ku-Band antennas
and 200 for C-Band antennas).
SEARCH DELAY
– default, or any number of seconds from 1-255 that you would prefer that the
ACU wait before starting an automatic search.
SWEEP INC
– Larger antennas should have slower speeds and smaller antennas should have faster
speeds:
Larger
antennas should have slower speeds set to
0047
(= 5 degrees/second) for
2.4M to
3.6M antenna systems
).
Mid size
antennas can be driven a little faster, set to
0063
(= 8 degrees/second) for
2M
antennas models
).
Smaller
antennas should have faster speeds, set to
0079
(= 18 degrees/second) for
all
0.8M to 1.5M antenna models)
.
GYRO TYPE
–
MUST
be set to
zero
for this search pattern.
SAT REF
mode –
MUST
be
ON
for this search pattern.
Target any satellite longitude value which includes even tenths digit values (ie SAT 101.0 W or SAT 101.2 W).
If the desired satellite longitude includes an odd tenths digit, you must round it up, or down, one tenth to
make the tenths digit EVEN. The Antenna Control Unit calculates the Azimuth, Elevation and Polarization
values it will use to target the antenna. However, without heading input, the ACU cannot target a “true
azimuth” position (relative to true North). It will target the antenna to the calculated elevation and a
repeatable “Start” relative azimuth position. In Series 04 antennas this relative position will be 90 degrees
away from the nearest mechanical stop. In all other antennas it will be 000 degrees relative.
Initially the antenna will go to the “Start” relative azimuth position at the calculated elevation. Then the
antenna will search up 450 degrees in azimuth, search up one Search Increment in elevation, search down
450 degrees in azimuth, search down two Search Increments in elevation, etc until Search Limit is reached.
When the end of the search pattern is reached, the ACU will retarget the antenna back to the start point
shown in the graphic below.
If the desired signal is found (AND network lock is achieved in the satellite modem) at this position, or
anywhere within the search pattern, the ACU will terminate search and go into Tracking mode. If the desired
signal is not found the ACU will wait SEARCH DELAY seconds and then begin the search pattern again. This
cycle will repeat until the desired satellite signal is found or the operator intervenes.
Summary of Contents for DAC-2202
Page 8: ...Introduction DAC 2202 Antenna Control Unit 1 2 THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 32: ...Installation DAC 2202 Antenna Control Unit 4 6 THIS PAGE INTENTIONALLY LEFT BLANK ...
Page 50: ...Functional Testing DAC 2202 Antenna Control Unit 6 4 This Page Intentionally Left Blank ...
Page 106: ...Technical Specifications DAC 2202 Antenna Control Unit 9 6 This Page Intentionally Left Blank ...
Page 108: ...Drawings DAC 2202 Antenna Control Unit 10 2 This Page Intentionally Left Blank ...
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