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<blockquote data-quote="Channel Hopper" data-source="post: 996533" data-attributes="member: 175144">Apologies, I missed this post.The usual method of reducing cross polarity effect at source is to do exactly what you have achieved, by tilting the whole antenna reflector on the boresight. This only goes some way towards a cure since deficiencies within the system remain, owing to the reflector and feed design.Changing to a highly elliptical shaped antenna<a href="http://www.satellite-bandwidth.net/NewEra-2015/equipment-manuals/Prodelin/ds-ku-0.95-1950-1951.pdf" target="_blank">http://www.satellite-bandwidth.net/NewEra-2015/equipment-manuals/Prodelin/ds-ku-0.95-1950-1951.pdf</a>(and suitably matched feed as per the following) will remove more of the unwanted polarity signal,<img src="http://patentimages.storage.googleapis.com/pages/US5552797-5.png" alt="" class="fr-fic fr-dii fr-draggable " style="" />however there is further improvement by use of a dedicated one polarity waveguide and WR75 (at Ku band) matching feed adapter, preferably tuned to around 250MHz of the frequency that is being received.There are further design changes that can be made, though this does involve highly specialised waveguide tuning, and dual reflector technology, in the next post if you are still awake.</blockquote>

[QUOTE="Channel Hopper, post: 996533, member: 175144"] Apologies, I missed this post. The usual method of reducing cross polarity effect at source is to do exactly what you have achieved, by tilting the whole antenna reflector on the boresight. This only goes some way towards a cure since deficiencies within the system remain, owing to the reflector and feed design. Changing to a highly elliptical shaped antenna [URL]http://www.satellite-bandwidth.net/NewEra-2015/equipment-manuals/Prodelin/ds-ku-0.95-1950-1951.pdf[/URL] (and suitably matched feed as per the following) will remove more of the unwanted polarity signal, [IMG]http://patentimages.storage.googleapis.com/pages/US5552797-5.png[/IMG] however there is further improvement by use of a dedicated one polarity waveguide and WR75 (at Ku band) matching feed adapter, preferably tuned to around 250MHz of the frequency that is being received. There are further design changes that can be made, though this does involve highly specialised waveguide tuning, and dual reflector technology, in the next post if you are still awake. [/QUOTE]

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