[opendtv] Re: Post on alt.tv.tech.hdtv of interest today
- From: Bob Miller <bob@xxxxxxxxxx>
- To: opendtv@xxxxxxxxxxxxx
- Date: Mon, 04 Apr 2005 22:10:22 -0400
Manfredi, Albert E wrote:
>Bob Miller wrote:
>
>
>
>>BTW I am still having my calls to broadcasters returned.
>>
>>Key interest seems to be the need for MPEG4 and receiver
>>standards which then opens the door to consideration of
>>looking at modulation.
>>
>>
>
>Interesting to see if this leads to anything. My inclination would be to "pick
>your battles," so you don't end up turning everyone off by asking for things
>they cannot give you.
>
>
The hearing priorities are first to address receiver standards and to
see if they would be addressed by any Congressional converter
distribution program. Second would be the issue of MPEG4. If that
becomes a front burner issue then that opens the door to a discussion of
modulation. If we are going to change to MPEG4 we might as well look at
all possible modulations or even a non-compatible version of 8-VSB since
all receivers would be made obsolete by a conversion to MPEG4.
I think from those I have talked to that the receiver issue and
especially MPEG4 are key.
>As to inkyblacks' rant,
>
>1. A US version of COFDM should certainly include the optional inner
>interleaver, to correctly solve the impulse noise problem. No reason to do
>something wrong if you're starting from scratch.
>
>
All modulations currently in use or proposed should be considered
including ISDB-T.
>2. A US version of COFDM should also mandate that all receivers be capable of
>receiving SD, ED, or HD streams, to avoid the simulcast requirement of other
>COFDM countries. And might as well include H.264 while you're at it.
>
>
Obviously all receivers should be capable of 1080P, I don't understand
why France chose to go with MPEG2 for their FTA while allowing MPEG4 on
pay channels at this late date.
>3. The bit about bandwidth required by COFDM vs 8-VSB is perhaps not entirely
>justified. I think Mark Schubin indicated that the FCC aloowed the slightly
>wider COFDM 6 MHz spectrum. Maybe this is because while 8-VSB channels are
>down 50 dB at +/- 1 Mhz of the 0dB level of the spectrum, the dropoff of 8K
>COFDM is steeper. So in essence, COFDM even with 5.71 MHz bandwidth might be no
>wider by the 30 dB point than 8-VSB is with 5.38 MHz of bandwidth. That's what
>the spectra seem to indicate.
>
>Before settling on any new modulation scheme, though, I'd rather see a
>performance spec be written. And a meaningful one, not one obviously loaded to
>give a predetermined answer. My spec would include relatively long range
>indoor reception of full power UHF signals,
>for example, which would *really* make OTA easy for users to set up.
>
>
ajb3000 wrote on digitalspy yesterday...
"At home I'm 36 miles from the transmitter and get all muxes (bar the
sky one) with a 20 year old aerial installation and dodgy wiring, god
bless the Crystal Palace transmitter"
Crystal Palace has 6 20 kW ERP transmitters. ajb3000 receives them all
fine at 36 miles.
Gazza487 wrote 3/30/05....
"Yeah I got my power arc aerial from there. it needs 2 batteries once in
a blue moon (use some good duracells) it lives ontop of my wardrobe and
is very happily picking up all muxes.
I'm abt 30 miles from sutton coldfield"
Sutton Coldfield has six transmitters. 4 at 8 kW and two at 10 kW. His
power arc antenna is an omni. He is picking up all six stations indoors
with a simple antenna at 30 miles.
I think both of these gentlemen would tell you their set up was easy.
Bob Miller
>Bert
>
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