>>> Thanks for the information. I am still totally bemused by all this. I
>>> can remember when BBC television was on Band I and ITA was on Band
>>> III. As far as I can remember, Band I contained channels 1 to 5 and
>>> Band III contained channels 6 to 13. AIUI each TV channel is divided
>>> into four DAB multiplexes. On this basis, Band III has capacity for a
>>> total of 32 multiplexes. As far as I can see, only four are in use in
>>> this area.
>>>
>>> Why can't they just double the number of multiplexes and double all
>>> the bitrates?
>>
>>What would really sort out DAB is if they used 64QAM the same as Radio via
>>Freeview, then all the bitrates could be TRIPLED without allocating any
>>more
>>multplexes.
>>
>>The argument against this was quality of mobile reception, but 64QAM would
>>work just as well as the present DAB if the transmitter powers were
>>increased to the same levels as FM. Currently DAB uses much lower power,
>>10
>>kW where an equivalent national FM transmitter uses 240 kW. 64QAM would
>>need
>>160 kW to match the mobile coverage.
>
> Would this be compatible with the existing radios?
No.
> If not, if new radios are needed, would it not be better to use DAB+
> rather than
> using 16 times more power, which hardly seems consistent with any
> 'green' agenda?
AFAIK DAB+ doesn't have a 64QAM or 16QAM option either. 16 QAM (like they
used to use on Freeview) would be good too, DOUBLING all the bitrates with a
power increase to only 40 kW in the above example.
16 QAM would make switchover to DAB+ much easier by making better use of the
exisiting spectrum.
>>> can remember when BBC television was on Band I and ITA was on Band
>>> III. As far as I can remember, Band I contained channels 1 to 5 and
>>> Band III contained channels 6 to 13. AIUI each TV channel is divided
>>> into four DAB multiplexes. On this basis, Band III has capacity for a
>>> total of 32 multiplexes. As far as I can see, only four are in use in
>>> this area.
>>>
>>> Why can't they just double the number of multiplexes and double all
>>> the bitrates?
>>
>>What would really sort out DAB is if they used 64QAM the same as Radio via
>>Freeview, then all the bitrates could be TRIPLED without allocating any
>>more
>>multplexes.
>>
>>The argument against this was quality of mobile reception, but 64QAM would
>>work just as well as the present DAB if the transmitter powers were
>>increased to the same levels as FM. Currently DAB uses much lower power,
>>10
>>kW where an equivalent national FM transmitter uses 240 kW. 64QAM would
>>need
>>160 kW to match the mobile coverage.
>
> Would this be compatible with the existing radios?
No.
> If not, if new radios are needed, would it not be better to use DAB+
> rather than
> using 16 times more power, which hardly seems consistent with any
> 'green' agenda?
AFAIK DAB+ doesn't have a 64QAM or 16QAM option either. 16 QAM (like they
used to use on Freeview) would be good too, DOUBLING all the bitrates with a
power increase to only 40 kW in the above example.
16 QAM would make switchover to DAB+ much easier by making better use of the
exisiting spectrum.
Source: http://www.homecinemabanter.com/showthread.php?t=73587&goto=newpost
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