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Fringe Reception General
Problems getting 53E
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<blockquote data-quote="Channel Hopper" data-source="post: 479618" data-attributes="member: 175144"><p>Of course.</p><p></p><p>The suggestion that all satellite transponder polarisations 'magically' align themselves at a particular location is part and parcel of the myth of selling domestic components (Universal LNBs ) by the trade.</p><p></p><p>For the main part, a fixed satellite installation will be unaffected by the correct alignment of the LNB in one polarisation, owing to the cross polarisation rejection of the LNB. In reality, a lot of satellites are actually transmitting at locations well away from the shortest distance to them (away from the equator and away from the nearest longitude),and therefore the individual transponders are adjusted by the satellite operators to optimise the delivery of signal by adjustment of downlink 'skew' on the satellite.</p><p></p><p>Additionally as the satellite received drops away from the high point in the geostationary arc, the two (and sometimes more than two) polarisations will often be no longer at 90 degrees to each other, in relation to the receiving station, as a result of the signal paths being at a slant to the viewer, and so the opposite polarisation to the one being received may not be filtered out totally by the universal LNB mechanical /electronic design.</p><p></p><p>Mechanical (de)polarisers are still used in the more professional set ups to reject the opposite polarisations directly after the feedhorn, to maximize the incoming signal to noise of a bank of transponders, before they hit the front end of an LNB, negating the compromise of port design in the all port (C120) entry path of universal LNB's. </p><p></p><p>This programme is utilised to set up a fully motorised system using a mechanical polariser on a per satellite basis, but it also shows the individual satellite down path slants when the correct parameters of the receive site are inserted into the fields.</p><p></p><p><a href="http://www.arachnoid.com/satfinderonline/index.php" target="_blank">http://www.arachnoid.com/satfinderonline/index.php</a></p></blockquote><p></p>
[QUOTE="Channel Hopper, post: 479618, member: 175144"] Of course. The suggestion that all satellite transponder polarisations 'magically' align themselves at a particular location is part and parcel of the myth of selling domestic components (Universal LNBs ) by the trade. For the main part, a fixed satellite installation will be unaffected by the correct alignment of the LNB in one polarisation, owing to the cross polarisation rejection of the LNB. In reality, a lot of satellites are actually transmitting at locations well away from the shortest distance to them (away from the equator and away from the nearest longitude),and therefore the individual transponders are adjusted by the satellite operators to optimise the delivery of signal by adjustment of downlink 'skew' on the satellite. Additionally as the satellite received drops away from the high point in the geostationary arc, the two (and sometimes more than two) polarisations will often be no longer at 90 degrees to each other, in relation to the receiving station, as a result of the signal paths being at a slant to the viewer, and so the opposite polarisation to the one being received may not be filtered out totally by the universal LNB mechanical /electronic design. Mechanical (de)polarisers are still used in the more professional set ups to reject the opposite polarisations directly after the feedhorn, to maximize the incoming signal to noise of a bank of transponders, before they hit the front end of an LNB, negating the compromise of port design in the all port (C120) entry path of universal LNB's. This programme is utilised to set up a fully motorised system using a mechanical polariser on a per satellite basis, but it also shows the individual satellite down path slants when the correct parameters of the receive site are inserted into the fields. [url]http://www.arachnoid.com/satfinderonline/index.php[/url] [/QUOTE]
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Fringe Reception General
Problems getting 53E
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