Astra 2F at 28.2E: General Discussion

[wallycharlo]

Excuse my ignorance .. But, does this confirm that 2f is banjaxed ?

 

[Lazarus]

No.

No known problem.

All according to plan.

Probably.

The only thing truly banjaxed (great word, BTW) is the speculation that never really correlated with reality.

 

[satesco]

Now I just make a guess, but it's strange that the signal is very strong;and for this reason I think new freq. is on Astra 2F.I think it's a test transponder for Data!

 

[Lazarus]

True FEC also called code rate is the inner coding (convolutional). But there's more redundancy. The outer coding (Reed Solomon) uses 204 byte for each 188 byte ts_packet.
A DVB-S symbol rate of 22MS/s and FEC of 5/6 resulting in a brutto bit rate of 22*2=44Mbit/s with a net bit rate of 44*(188/204)*(5/6)=33,79 Mbit/s

Yes, it's pretty much bread-and-butter stuff for decent Installers and wannabe Comms. buffs (Counting myself in the latter category, albeit on a "Gosh it was a long time ago" basis, having studied Error Detection and Correction at Uni in the dark ages and applied it in the design of SatComms equipment as a young Microwave Systems Engineer).

An interesting Topic that's almost heading for a Thread of its own!

 

[solly]

i got it very low signal i lock it
i hope 2f will be pan europe beam more stronger

 

[davidcmadrid]

Sorry if I missed this but does anybody have an opinion as to why 11023h is the apparently more problematic transmission in border line setups? Is it something to do with fec?

 

[Analoguesat]

Probably as its DVB-S2. That seems to need stronger signals to produce a resilient signal.

 

[C0re]

And don't forget the 8PSK modulation!

 

[Huevos]

Sorry if I missed this but does anybody have an opinion as to why 11023h is the apparently more problematic transmission in border line setups? Is it something to do with fec?

Almost no difference. DVB-S2 8PSK 2/3 = 6.6dB SNR threshold, DVB-S QPSK 5/6 = 6.5dB threshold, according to Lyngsat. Before the BBC changed parameters on the BBC HD transponder that was DVB-S2 QPSK 8/9 = 6.2dB threshold. 10936V is also using this configuration.

 

[Huevos]

1/2 FEC means half the data is error correction. A higher FEC of 7/8 means 1/8 of data is error correction.

Thanks. I got confused. Was thinking is was a ratio, not a vulgar fraction.

 

[timo_w2s]

Almost no difference. DVB-S2 8PSK 2/3 = 6.6dB SNR threshold, DVB-S QPSK 5/6 = 6.5dB threshold, according to Lyngsat. Before the BBC changed parameters on the BBC HD transponder that was DVB-S2 QPSK 8/9 = 6.2dB threshold. 10936V is also using this configuration.

But in reality some receivers do seem more fussy. Could some tuners just be more sensitive to DVB-S or QPSK?

 

[Huevos]

But in reality some receivers do seem more fussy. Could some tuners just be more sensitive to DVB-S or QPSK?

Maybe, but that would be a fault with the receiver, not a feature of the modulation. But anyway some transponders just are stronger than others irrespective of modulation. For example from 1N I receive 10891H at 13.6 dB, and 10936V at 15.7dB. That is probably about a 50% difference in dish size (70cm to 1m).

 

[timo_w2s]

Maybe, but that would be a fault with the receiver, not a feature of the modulation. But anyway some transponders just are stronger than others irrespective of modulation. For example from 1N I receive 10891H at 13.6 dB, and 10936V at 15.7dB. That is probably about a 50% difference in dish size (70cm to 1m).

Yes true, I've noticed that some transponders come in stronger than others and it's probably the case here too. Wouldn't it have been nice if they could light up new satellites for a few days with equal test transmissions on all transponders so we could all check levels...

 

[Juan69]

But is that surprising? - if the skew is set properly for 28.2E then it makes sense that changing it will worsen the signals - if you say the set up was good then the 5 cluster is not weaker because the skew is wrong but because the signal is not as good - or have I missed the point? SQ is very dependent on the correct skew

Take your point. Tomorrow I shall finish harvesting my olives, then it may be worthwhile changing my current LNB for a black Inverto I have in the garage. Its still in its box and may help. Might bring my 5 cluster back. Or maybe not.

 

[ceetee]

At least that puts speculation to bed, guess the 2A or 2B transition to 2F will now take place after Christmas. I assume 2G will eventually cover all of Bands C and D too so as to offer full redundancy to 2E and 2F. I presume therefore 2D is still hanging around as a current backup to 1N (and later next year 2E's) Band D TP's, with it not in use and housekeeping kept to a minimum it will save the craft fuel.

Don't SES Astra/SKY advise what their plans are? If not why not? What is the big deal?
I have family in Spain, along with 1000s of others down there they receive SKY using a viewing card issued to
their UK address. SKY know this - do SKY really want to lose millions of revenues by messing everyone about?
They should publicly announce their plans to migrate from 2A and 2B to 2F or whatever!
Carole

 

[Lazarus]

Why? BSkyB and the UK PSBs exist to Broadcast to an intended audience in the UK. Any Transponder or Satellite moves have no effect on the intended audience.

The fact that there has been (and still will be) overspill is a bonus for those outside the UK and BSkyB and the UK PSBs are not in a position to condone that by effectively acknowledging and advertising the fact - although in BSkyB's case it is certainly true that they welcome Revenue from any source and only seem to clamp down on improper usage when obliged to do so (Retransmission systems; Card sharing; Non-UK "Agencies" etc.)

As for the big deal ................. part of it is the amount paid for (and the conditions attached to) Programme Rights. Part of it is the terms of their own Broadcasting Licenses. There are many factors, including Commercial, Legal, Copyright etc.

You hit upon part of the answer yourself in mentioning Cards issued to a UK address. There is no mechanism or mandate for Cards to be properly issued to anywhere other than a UK (or RoI) address.

 

[ceetee]

Why? BSkyB and the UK PSBs exist to Broadcast to an intended audience in the UK. Any Transponder or Satellite moves have no effect on the intended audience.

The fact that there has been (and still will be) overspill is a bonus for those outside the UK and BSkyB and the UK PSBs are not in a position to condone that by effectively acknowledging and advertising the fact - although in BSkyB's case it is certainly true that they welcome Revenue from any source and only seem to clamp down on improper usage when obliged to do so (Retransmission systems; Card sharing; Non-UK "Agencies" etc.)

As for the big deal ................. part of it is the amount paid for (and the conditions attached to) Programme Rights. Part of it is the terms of their own Broadcasting Licenses. There are many factors, including Commercial, Legal, Copyright etc.

You hit upon part of the answer yourself in mentioning Cards issued to a UK address. There is no mechanism or mandate for Cards to be properly issued to anywhere other than a UK (or RoI) address.

Thanks for that. Why is the Roi OK but not other EU States such as Spain then? Roi is not part of the UK either!
And what happened to the EU Directive that says an EU Citizen moving residence to another EU State should be
permitted to subscribe (= continue to subscribe) to satellite services transmitted from his "home" State?
Carole.

 

[Analoguesat]

Because thats the way the Sky operation was licenced to start with

 

[PaulR]

The RoI is a separate market for $ly. They have the programme rights for there and their service is tailored to suit with RT1, 2 etc replacing the Beeb, ITV, C4 and C5 in channel line up.

Northern Ireland is a special case where, although part of the UK and therefore using the UK line up, because of cultural ties they also have most of the RTE, etc channels.

 

[C0re]

Still no reports for a switch of 2B (or 2A) transponders to the 2F?