[opendtv] Re: Which Modulation Would You Choose on a really bad day?
- From: "Donald Koeleman" <donald.koeleman@xxxxxxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Mon, 18 Sep 2006 19:19:59 +0200
They tend to not like this when I say this, as this 'Portable B' network is
their pride and joy and they have been promoting and promising indoor and
portable reception since the second half of the nineties, but from personal
experience (and those of others) I can tell you that indoor reception leaves
a LOT! to be desired, even on a so-called DVB-T Portable B network. I can
see the reasons for this such as limited transmission power, but the issue
remains.
A few years ago there were the usual complints about the coverage of the
radiostations that have a task in emergy warning, guess what one of the
responsible cabinet members said, whell we can always send sent soundtrucks,
vans with a megaphone on the rooftop, so guess what infrastructure is in
place with respect to the Digital Terrestrial Broadcasting service...
I.e. even COFDM might not be the answer.
d.
----- Original Message -----
From: "Stephen W. Long" <longsw@xxxxxxxxxxxxxx>
To: <opendtv@xxxxxxxxxxxxx>
Sent: Monday, September 18, 2006 2:27 AM
Subject: [opendtv] Which Modulation Would You Choose on a really bad day?
> It might be useful to restate why, in my official capacity, I ever even
> cared about DTV Modulation. For me and my organization it was simple -
when
> you need to get data bits to the American public in times of crisis, which
> modulation system would yield the best balance of signal receivability,
> commercial product viability, and data rate. The largest reason I became
a
> supporter of the DVB version of COFDM was the fact that all receivers had
> the ability to accept all defined transmission modes. So for routine
daily
> business, markets could maximize data rate to deliver HDTV and one or two
> sub channels. When the community (or Nation) was having a bad day, the
> transmitter sites could seamlessly switch into the lower data rate, but
very
> robust transmission mode, allowing signals to punch through, even in the
> face of poor reception conditions (like major weather events). This
ability
> to have a robust mode, to support mobile and emergency communications
needs,
> was never even considered by the 8VSB crowd.
>
> So my question remains today, as it did nearly nine years ago now - will
> 8VSB support the communications needs of our citizens when they need it
> most. If I can not receive 8VSB today, with a newest generation not so
> miracle chip, when I live only 20 miles from the transmitters, what will
> happen on a worst possible day, when people are hiding in their basements?
> I had to hide in my basement when a tornado passed within 1 mile of my
> house, and my wife and I watched the progress of the tornado on my local
> news station, seeing the radar, using a battery capable TV set, using its
> built in whip antenna. We got an acceptable analog picture, even in the
> basement.
>
> 8VSB does NOT replicate the receivability of NTSC. Until it does, it
> remains the wrong choice for the NTSC replacement. The only question
> remaining in my mind is, who is going to have to clean up the mess after
the
> analog switch over, when everyone starts discovering the hard way that
8VSB
> can not be received by simple indoor antennas in challenging but realistic
> echo environments. God help the poor soles working on the TV station
> switchboards in the days after switchover. I got started in the TV
business
> 34 years ago when I manned the night switchboard at my home town NBC
> affiliate station. If we went off the air, my evening was a living hell.
> We actually would lock the doors at night because we had had irate viewers
> drive by the station to cuss out out.
>
> Here is the true best question to ask all of those on this list - if their
> families lives depended on receiving information (or having their fire
> department receive information) using DTV transmission facilities, which
> modulation would you pick - 8VSB which works poorly when it works at all,
or
> a flexible modulation standard that can be tuned to punch through the
worst
> conditions to be received my moving vehicles moving at speed on a Las
Vegas
> highway (any of you remember that NAB experience)?
>
> Enough for now. Justice will out when analog is cut off. Let's see who
is
> standing at the end of the game, not just in the middle of the game.
>
> Stephen
>
> -----Original Message-----
> From: opendtv-bounce@xxxxxxxxxxxxx
> [mailto:opendtv-bounce@xxxxxxxxxxxxx]On Behalf Of Frank Eory
> Sent: Sunday, September 17, 2006 4:04 PM
> To: opendtv@xxxxxxxxxxxxx
> Subject: [opendtv] Re: 20060912 Twang's Tuesday Tribune (Mark's Monday
> Memo)
>
>
> >
> >
> >I have been quiet a long time on this list, but have to add a comment
here.
> >I just bought an integrated 32 LCDTV, HDTV, ATSC receiver. The digital
> >reception at my house is AWFUL - I have tried using three different
indoor
> >antennas and I can only receive ONE digital TV channel. I live 20 miles
> LOS
> >from the transmitters in DC. I can reliably receive multiple analog
> signals
> >(no low band VHF, but the high band and UHF are fine). I have a roof
> >mounted antenna, which significantly improves my analog reception, but
does
> >nothing to improve digital reception - the reflections kill effective
> >digital reception. The new TV has power meters which helps one point the
> >indoor antenna to get a signal. I can get reasonable (green) signal
> >strength, but the tuner will not lock up the signal - too much echo for
> this
> >newest generation receiver chip to handle. This has been the case with
> >EVERY 8VSB receiver tried in my house.
> >
> >8VSB remains crap. It has become clearer to me over the years that 8VSB
> was
> >chosen to let OTA TV die - the FCC wants people to move over to satellite
> >and cable so that the OTA frequencies can be sold or used for ground
mobile
> >applications.
> >
> >It will be delicious to watch the powers that be melt down in the days
> after
> >the cut off of analog.
> >
> >We had a chance to do something right (select COFDM) for the nation, and
> >vested interests blew it for the rest of us.
> >
> >When it all melts down and people start having hearings on what went
wrong,
> >I plan to be on the witness list, I will volunteer to head the committee
> >that drafts a new set of specifications for advanced television for our
> >nation.
> >
> >Stephen Long
> >
>
> By the time it all melts down it won't matter. OTA broadcasting gets
> more marginalized every day, and as new forms of distribution gain
> acceptance, OTA becomes increasingly irrelevant -- whether the
> modulation works or not. "Wireless TV" will be something intended only
> for portable devices. It won't be transmitted or received on the FCC's
> allocated DTV frequencies and the modulation won't be 8-VSB. Of course,
> it won't be free either.
>
> -- Frank
>
>
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