Field Replacement Procedure
Following legal entities are trading as / doing business as Cobham SATCOM
Thrane and Thrane A/S, Kgs. Lyngby, Denmark
Sea Tel Inc., Concord USA
TracStar Systems Inc., Orlando, USA
Omnipless Manufacturing (Pty) Limited, Cape Town, RSA
www.cobham.com/satcom
SAILOR 100 TV & SAILOR 800, 900A & 900B VSAT – Polarization Motor Module
(PMM) Procedure
Brief Summary:
Troubleshooting document for inspecting and replacing the polarization motor module (S-62-131002)
on the SAILOR 100 (7309A) TV antenna and SAILOR 800 (7008A), 900A (7009A) and 900B (7009B)
VSAT antennas.
Checklist:
Status LEDs
Events List / Error Log. Identify Defective Part
Replace Part
Verify Initialization and Run POST Test
Theory of Operation:
The Polarization Motor Module (PMM) controls the polarity angle of the antenna by aligning the
polarization unit on the back of this dish at the correct angle to match the linear satellite signal from
the vessels GPS location for optimum signal strength. On the SAILOR 800 and 900 VSAT antennas this
will also ensure the transmit signal is correctly aligned to prevent interference with the services on the
opposite polarity.
The PMM drives a stepper motor on the back of the dish to rotate the polarization unit of the VSAT
antennas or the LNB of the TV antenna, based on commands from the Pedestal Control Module (PCM)
to optimise the polarity look angle of the system.
The polarity angle is calculated using the GPS position of the vessel and the look angle to the desired
satellite. Upon initialization the position of the VSAT polarization unit is calibrated using a reference
point (magnet) on the polarization unit and a Hall Effect sensor installed on the Zero Reference
Module (ZRM) on the polarization axis. Whereas the TV antenna drives the polarity stepper motor
from end-stop to end-stop to verify the full range of motion and calibrate its position.
Once calibrated the VSAT antennas use an encoder installed on the polarization unit to count the
increments/decrements of the polarization drive and provides this feedback to the PCM as a reference,
where as the TV antenna counts the steps of the polarization motor to calculate the angle of the LNB.
Cobham SATCOM
Global Customer Service dept.
Document no.: 97-138940-D
Revision: D
Date: April 2013
