Reply to thread

Message

<blockquote data-quote="Fisty McB" data-source="post: 929747" data-attributes="member: 389824">Rough capacity calculation - current DVB-S transmissions with SR 27500 &amp; FEC 2/3 gives a net data rate of 33.79 Mbit/s.Retaining the same symbol rate but changing the FEC gives the following capacity...3/4 - 38.02 Mbit/s5/6 - 42.24 Mbit/s7/8 - 44.35 Mbit/sSo changing the FEC to 5/6 will give roughly 8.5 Mbit/s more data, surely more tempting to change to considering signal levels now in the core reception area.Also the current 11224 V transmission (transponder C2L) is DVB-S despite only carrying HD channels and could surely convert over to DVB-S2 in due course as well once it gets bounced on to the Astra fleet. I'll just go through some common/popular values...DVB-S2, SR 29500 (higher symbol rate available, same as used by Sky for 36 MHz transponders between 11.7 - 12.5 GHz)...QPSK 2/3 - 39.01 Mbit/sQPSK 3/4 - 43.88 Mbit/s (used by Sky on some transponders)QPSK 5/6 - 48.81 Mbit/sQPSK 9/10 - 52.76 Mbit/s8PSK 2/3 - 58.43 Mbit/s (used by Sky &amp; BBC on FSS band transponders with a SR 23000)8PSK 3/4 - 65.73 Mbit/s (used by ITV on 11053 H with SR 23000)8PSK 5/6 - 73.18 Mbit/s (tested earlier this year by SES &amp; ITV)So if they changed the 11224 V transponder in the future to DVB-S2 8PSK SR 29500 FEC 3/4, they could nearly double their data rate capacity.</blockquote>

[QUOTE="Fisty McB, post: 929747, member: 389824"] Rough capacity calculation - current DVB-S transmissions with SR 27500 & FEC 2/3 gives a net data rate of 33.79 Mbit/s. Retaining the same symbol rate but changing the FEC gives the following capacity... 3/4 - 38.02 Mbit/s 5/6 - 42.24 Mbit/s 7/8 - 44.35 Mbit/s So changing the FEC to 5/6 will give roughly 8.5 Mbit/s more data, surely more tempting to change to considering signal levels now in the core reception area. Also the current 11224 V transmission (transponder C2L) is DVB-S despite only carrying HD channels and could surely convert over to DVB-S2 in due course as well once it gets bounced on to the Astra fleet. I'll just go through some common/popular values... DVB-S2, SR 29500 (higher symbol rate available, same as used by Sky for 36 MHz transponders between 11.7 - 12.5 GHz)... QPSK 2/3 - 39.01 Mbit/s QPSK 3/4 - 43.88 Mbit/s (used by Sky on some transponders) QPSK 5/6 - 48.81 Mbit/s QPSK 9/10 - 52.76 Mbit/s 8PSK 2/3 - 58.43 Mbit/s (used by Sky & BBC on FSS band transponders with a SR 23000) 8PSK 3/4 - 65.73 Mbit/s (used by ITV on 11053 H with SR 23000) 8PSK 5/6 - 73.18 Mbit/s (tested earlier this year by SES & ITV) So if they changed the 11224 V transponder in the future to DVB-S2 8PSK SR 29500 FEC 3/4, they could nearly double their data rate capacity. [/QUOTE]

Verification