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<blockquote data-quote="Channel Hopper" data-source="post: 1031754" data-attributes="member: 175144">I was talking about this position only though I had forgotten about the type of bus (Astra 1KR is of similar manufacture but without the Ka band kit installed - allegedly).The active transmissions at 18GHz are provided by two transponders and from memory they are on opposite linear polarities. In order to improve the reception by a margin, one could use a dedicated single polarity LNB and matched rectangular port transfer from the feed, or perhaps a dedicated one piece feed/transfer if one can be constructed. The other option would be to rotate the offset dish by 90 degrees, so that the elipse is better at removing the side lobes in the orbital plane, and possibly aligning the dish at the correct skew angle of the equatorial arc to peak the cross-pol rejection mechanically.Since the orbital slot around 19E is rather crowded, not only with the official commercial satellites, but a couple of classified/military birds, it might be the incoming noise from the thousands of different transmissions are swamping the tuner input, and the filters at the band stops let some of it through.In the second case, increasing the dish size, whilst narrowing the beamwidth, is unlikely to remove the unwanted signals unless you are talking about diameters of above 5m to limit this below 0.5 of a degree or so.</blockquote>

[QUOTE="Channel Hopper, post: 1031754, member: 175144"] I was talking about this position only though I had forgotten about the type of bus (Astra 1KR is of similar manufacture but without the Ka band kit installed - allegedly). The active transmissions at 18GHz are provided by two transponders and from memory they are on opposite linear polarities. In order to improve the reception by a margin, one could use a dedicated single polarity LNB and matched rectangular port transfer from the feed, or perhaps a dedicated one piece feed/transfer if one can be constructed. The other option would be to rotate the offset dish by 90 degrees, so that the elipse is better at removing the side lobes in the orbital plane, and possibly aligning the dish at the correct skew angle of the equatorial arc to peak the cross-pol rejection mechanically. Since the orbital slot around 19E is rather crowded, not only with the official commercial satellites, but a couple of classified/military birds, it might be the incoming noise from the thousands of different transmissions are swamping the tuner input, and the filters at the band stops let some of it through. In the second case, increasing the dish size, whilst narrowing the beamwidth, is unlikely to remove the unwanted signals unless you are talking about diameters of above 5m to limit this below 0.5 of a degree or so. [/QUOTE]

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