Nera SatLink 1000, Руководство пользователя

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Nera SatLink Terminal User Guide – Revision P
96
G.3.2 Polarisation alignment
Rotate the complete feed-system (horn, LNB and
transmitter) very slowly and carefully in one
direction away from the coarse polarisation
alignment. Monitor the spectrum-analyser and
observe the carriers on the opposite polarisation.
Correctly adjusted, the carriers should disappear
or have a much lower level than the carriers with
the correct polarisation. Rotate in the opposite
direction if you do not observe disappearing
carriers.
The polarisation alignment must be performed with a high degree of accuracy. Note that the cross-
polar discrimination (XPD) requirement on transmitted signal may vary depending on the satellite
operator. During line-up, the control centre of the satellite operator will check if the terminal’s
XPD is sufficient and eventually ask the ODU installer to proceed with fine adjustment until the
XPD requirement is achieved.
Spectrum before polarisation
fine adjustment.