Uplink depolarization control implementation in satellite broadcasting feeder earth stations

In a TV-broadcast feeder earth station using a translated version of the WARC-77 downlink frequency plan it is possible to employ a single open-loop two-parameter control sub-system to adaptively reduce the uplink depolarization interference from all five national allocated carriers. It is shown that from the implementation standpoint, the most suitable depolarization control method for high power broadcasting earth stations is the 'auxiliary path' method. This relies on the generation of the control signal in a separate lower power path branched from the main signal path. A detailed error analysis is presented for the 'auxiliary path' control method based on the reception of a 12 GHz downlink beacon signal to provide the required atmospheric depolarization data, which is then frequency scaled to the uplink frequency. The results indicate that this is a viable method for forward atmospheric depolarization control in feeder links. There need be no constraints on feeder earth station location within the coverage area provided simple provisions are included in the control sub-system.