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Fringe Reception General
Dish size info for Nilesat 7W in western Europe & the UK
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<blockquote data-quote="Fisty McB" data-source="post: 877386" data-attributes="member: 389824"><p>The best way I get my head around FEC rates is to gather that the published rate shows that from the net data rate for a given transponder, the FEC rate is a fraction showing how much of the net data rate goes towards bitrate capacity, with the remainder being the error correction data. So for example an FEC of 1/2 gives 50% for general capacity and 50% for error correction. 2/3 gives 66.67% for capacity and 33.33% for error correction, right up to (for DVB-S) 7/8 being 87.5% & 12.5% respectively and (for DVB-S2) 9/10 being 90% & 10%.</p><p></p><p>The closer the FEC rate expressed like a fraction gets to 1, the less capacity there is given to error correction. The advantage for the broadcaster using a low (close to 1, though initially you would regard this as higher) FEC rate is a higher bitrate available for data capacity for the same symbol rate, at the expense of the receiver requiring a better signal to noise ratio. For most people this may require a tweaking of their dish set up to make sure their alignment is more accurate than before, or needing a larger dish. Hence as mentioned by another poster, a transponder going from an FEC of 3/4 to 5/6 needed to have their dish alignment tweaked to account for less error correction being transmitted and the higher s/n ratio required.</p></blockquote><p></p>
[QUOTE="Fisty McB, post: 877386, member: 389824"] The best way I get my head around FEC rates is to gather that the published rate shows that from the net data rate for a given transponder, the FEC rate is a fraction showing how much of the net data rate goes towards bitrate capacity, with the remainder being the error correction data. So for example an FEC of 1/2 gives 50% for general capacity and 50% for error correction. 2/3 gives 66.67% for capacity and 33.33% for error correction, right up to (for DVB-S) 7/8 being 87.5% & 12.5% respectively and (for DVB-S2) 9/10 being 90% & 10%. The closer the FEC rate expressed like a fraction gets to 1, the less capacity there is given to error correction. The advantage for the broadcaster using a low (close to 1, though initially you would regard this as higher) FEC rate is a higher bitrate available for data capacity for the same symbol rate, at the expense of the receiver requiring a better signal to noise ratio. For most people this may require a tweaking of their dish set up to make sure their alignment is more accurate than before, or needing a larger dish. Hence as mentioned by another poster, a transponder going from an FEC of 3/4 to 5/6 needed to have their dish alignment tweaked to account for less error correction being transmitted and the higher s/n ratio required. [/QUOTE]
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Fringe Reception General
Dish size info for Nilesat 7W in western Europe & the UK
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