Old round DirecTV dish -- salvagable for FTA use? (2 Viewers)

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Inclined Orbit

SatelliteGuys Pro
Jan 2, 2018
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249
Los Angeles
I'm not referring to Directv and Dish, which use high powered transponders. I'm referring to common FTA signals. Most now use 8PSK. I have extensive experience (attempting) to receive common S2 signals on small dishes, and I can tell you for a fact you can't tune a common FTA S2 8PSK signal on a DBS dish at this time. At least not within the past 3 years.
I think the problem here is making the general statement "That was 12 years ago, when everything was modulated as DVB-S. Now, (almost) everything is DVB-S2 or higher. This requires a larger dish."

That by itself has nothing to do with bit rates increasing by 2 or 3X and even with the performance advantages of DVB-S2 over older DVB, you can't close the link with the same size dish no matter what the FEC or modulation type due mainly to the higher bit rates. Nothing to due with DVB vs DVB-S2.
 
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Brct203

SatelliteGuys Pro
Dec 24, 2016
1,237
1,214
Connecticut
In the end, what matters is the combination of protocol, modulation and FEC... a DVB-S2 transponder using QPSK is easier to receive than its equivalent in DVB-S (using same FEC, so that we compare apples to apples). But then if you compare a typical DVB-S transponder like CGTN on 95W (FEC=3/4) that requires 5.5dB of CNR, to a DVB-S2 transponder using 8PSK with a FEC=5/6, so requiring 9.4dB, obviously that DVB-S2 transponder will be a lot more difficult to lock on an undersized dish. But for reference, there are also some DVB-S2 transponders that use QPSK with a FEC=1/2, requiring only 1dB of CNR (for example, AFN on 34.5W C-band, making it a reasonably easy target for mini BUDs)
 

Inclined Orbit

SatelliteGuys Pro
Jan 2, 2018
420
249
Los Angeles
Thanks, I'm aware of this and I appreciate details which point out the reasons why a particular combination of DVB-S2 transponder can't be received on an 18" dish vs an older DVB format with lower bit rates, etc.

BTW, I was at the AFN uplink center at March AFB last year helping with the change in parameters and dialing in the uplinks and measuring downlink performance on a very small C band dish with the old and new parameters.

In the end, what matters is the combination of protocol, modulation and FEC... a DVB-S2 transponder using QPSK is easier to receive than its equivalent in DVB-S (using same FEC, so that we compare apples to apples). But then if you compare a typical DVB-S transponder like CGTN on 95W (FEC=3/4) that requires 5.5dB of CNR, to a DVB-S2 transponder using 8PSK with a FEC=5/6, so requiring 9.4dB, obviously that DVB-S2 transponder will be a lot more difficult to lock on an undersized dish. But for reference, there are also some DVB-S2 transponders that use QPSK with a FEC=1/2, requiring only 1dB of CNR (for example, AFN on 34.5W C-band, making it a reasonably easy target for mini BUDs)
 
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