COBHAM Sea Tel 9711-56 IMA C Band, Installation Manual

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Sea Tel 9711-56 IMA Setup – Satellite Configuration
13-1
EAR Controlled - ECCN EAR99
13. Setup – Satellite Configuration
The values that these parameters are set to depends on the hardware configuration required for each satellite.
Configure each of the satellites that airtime services will be provided on so that any one of them can be selected,
remotely or by the user onboard. The satellite selection will in turn control the hardware on the antenna pedestal to
select the correct TX & RX hardware and the correct tracking settings.
Sea Tel provides quad-band LNBs as standard on the Ku-Band feed assemblies.
13.1. Searching Patterns
The MXP will initiate an automated search pattern after AGC falls below the current Threshold setting
(indicates that satellite signal has been lost). The SEARCH DELAY parameter sets the amount of delay, in
seconds that the MXP will wait after AGC has fallen below the threshold value before it starts a search. Below
are the choices of patterns that each satellite can be set to.
You configure the dimensions of these patterns MXP to use this pattern by using the Search Increment and
Search Limit parameters on the Satellite Configuration page.
13.1.1. Default “Spiral” (Box) Search Pattern
The factory default search pattern in the MXP is a “Spiral” pattern.
When a search begins;
The antenna will then search up in azimuth one Search
Increment, search up one Search Increment in elevation,
search down two Search Increments 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 MXP will retarget the antenna to the
calculated Azimuth and Elevation position of the desired
satellite (start 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 MXP will terminate search and go into Tracking mode. If the
desired signal is not found the MXP 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.
13.1.2. Inclined Orbit Search Pattern
Some older satellites, in order to save fuel to keep them exactly positioned over the Equator, are in
an inclined geosynchronous orbit. The satellite remains
geosynchronous but is no longer geostationary. From a
fixed observation point on Earth, it would appear to trace
out a figure-eight with lobes oriented north-southward
once every twenty-four hours. The north-south excursions
of the satellite may be too far off the center point for a
default box search pattern to find that satellite at all times
during the 24 hour period.
When a search begins;
Initially the antenna will go to a calculated position that is
half of SWEEP INCR degrees above, and perpendicular to,
the satellite arc (along the same angle as polarization for
the desired satellite). This position is the “Start” of the search pattern in the graphic above. Then the
antenna will drive down along the polarization angle SWEEP INCR degrees, step one Search