Bill I did ask this question in another post, but got no takers. I am
buying a Promax Explorer. The basic one is about £1500 but does not do
DVB-S2, the Explorer II does, but is another £750.

I read somewhere you can get a good indication of HDTV signal quality,
by reading a adjacent, standard DVB channels quality. In your opinion
is that about right?

I visualise quite a bit of HDTV upgrade work coming my way, would I be
doing myself a big dis-service by saving the 750 quid?

Mark in Spain

Anti-Spam wrote:
> Bill I did ask this question in another post, but got no takers. I am
> buying a Promax Explorer. The basic one is about £1500 but does not do
> DVB-S2, the Explorer II does, but is another £750.
> 
> I read somewhere you can get a good indication of HDTV signal quality,
> by reading a adjacent, standard DVB channels quality. In your opinion
> is that about right?

HD channels can share the same transport stream as SD channels. For 
instance BBC HD shares the same transponder and therefore stream as BBC 
1 Cambridge, and BBC 1 Channel Islands, both SD channels.

It is the signal strength and quality (aka BER) for the whole 
transponder stream that is important, and AIUI will be exactly the same 
regardless of the nature of the services contained within it.

"Mark Carver" <mark.carver@invalid.invalid> wrote in message 
news:6anjofF38db70U1@mid.individual.net...
> Anti-Spam wrote:
>> Bill I did ask this question in another post, but got no takers. I am
>> buying a Promax Explorer. The basic one is about £1500 but does not do
>> DVB-S2, the Explorer II does, but is another £750.
>>
>> I read somewhere you can get a good indication of HDTV signal quality,
>> by reading a adjacent, standard DVB channels quality. In your opinion
>> is that about right?
>
> HD channels can share the same transport stream as SD channels. For 
> instance BBC HD shares the same transponder and therefore stream as BBC 1 
> Cambridge, and BBC 1 Channel Islands, both SD channels.
>
> It is the signal strength and quality (aka BER) for the whole transponder 
> stream that is important, and AIUI will be exactly the same regardless of 
> the nature of the services contained within it.
>

Will it use the same encoding?  ITV is already worse than BBC on DTT because 
they use QAM 64 with (less error correction?) to cram more in.

R. Mark Clayton wrote:

> 
> Will it use the same encoding?  ITV is already worse than BBC on DTT because 
> they use QAM 64 with (less error correction?) to cram more in. 

Yes, Astra 28 satellite transmissions use QPSK modulation, 16 and 64 QAM 
are only used for DTT.

Remember all services within a satellite transponder (or DTT mux) are 
transmitted in sequential packets.  The more bandwidth (bit rate) an 
individual service requires, the higher percentage of packets it uses. 
HD services require a higher bit rate than SD, therefore more of the 
packets per stream are allocated to them.

Don't get confused with coding methods. SD uses MPEG2, HD MPEG4, that's 
at a totally different digital coding level, and has no effect on 
received signal or BER.