[opendtv] Re: Which Modulation Would You Choose on a really bad day?
- From: "negrjp" <negrjp@xxxxxxxxxx>
- To: "opendtv" <opendtv@xxxxxxxxxxxxx>
- Date: Mon, 18 Sep 2006 06:44:15 -0300
Dear Friends,
How about quadrature modulation used in dNTSC? I think this method is better
than 8VSB because Moviebeam uses this modulation system with indoor antenna.
TTFN
Jonas
from Brazil
> 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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