Setup - Satellite Configuration; Searching Patterns; Default "Spiral" (Box) Search Pattern; Inclined Orbit Search Pattern - Sea Tel 4012 GX KU-BAND Technical Manual

Setup – Satellite Configuration
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.
13.1.1.
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.
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 Increment to the right (parallel to
the satellite arc), 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 MXP will retarget the antenna to the calculated Azimuth and Elevation
point.
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Default "Spiral" (Box) Search Pattern

Inclined Orbit Search Pattern

4012 GX Dealer Technical Manual
Document. No. 136879 Revision B
13-1