Sea Tel 4009-9 BROADBAND-AT-SEA, Руководство по установке

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Setup –Optimizing Ku-Band Polarity and Cross-Pol Isolation 4009-9 Installation Manual
13-1
13. Setup –Optimizing Ku-Band Polarity and Cross-Pol Isolation
The only way to optimize the polarization of the antenna properly is to peak the polarity angle while the system is in auto-
polarization mode. This automatically adjusts the polarization of the feed by calculating the required polarization angle
for the feed every 2 seconds based on ship's latitude, longitude and the desired satellite longitude.
13.1. Sat Skew setting
The Satellite Skew setting in the Satellite – Tracking Receiver sub-menu (prior to NID) is used to enter the skew of
the satellite to optimize polarity angle.
This feature is used in conjunction with POL OFFSET to optimize polarization of the feed. POL OFFSET will serve
to calibrate the feed itself (mechanical calibration) Before adjusting the SKEW parameter, target a satellite that is
of your same longitudinal position (ie from Concord, CA at 38N and 122W we would target a satellite value of
122W). Drive the reflector to 0 or 5 degrees elevation (this is so you can easily view the feed). And verify that the
feed is a pure vertical. This may be visually verified by placing a level bubble on the LNB itself. During Cross-Pol
isolation tests, enter in the known skew value of the satellite, then as instructed by the NOC to drive the feed
assembly, increase or decrease the SAT SKEW parameter. Each digit represented on this screen represents one
whole degree of feed drive.
13.2. Polarity Angle (POLANG) Parameters
First make sure that the polang parameters are set correctly:
1. POL TYPE – should be set to 0072 (Auto-Pol mode).
2. POL OFFSET – This is initially set to factory default (0040) but will be incremented, or decremented, to
calibrate the feed to the horizon with a level (bubble or digital).
3. POL SCALE – Leave this at the factory default setting of 0090.
4. Go to the TX POLARITY parameter in the Setup menu of the ACU and set this parameter to your
assigned Transmit polarity (2=Horizontal or 4=Vertical).
5. Target your desired satellite (as provided by you airtime provider).
6. Verify the system has acquired the correct satellite, else continue searching until the correct satellite is
acquired, and set your satellite modem (or spectrum analyzer) to view its signal level display.
7. Allow tracking to peak the satellite signal.
8. SAT SKEW – This setting will be incremented, or decremented, to optimize the polarity to peak received
satellite signal, and later to do cross-pol isolation with the airtime provider, network operation center or
satellite provider.