[opendtv] Re: Which Modulation Would You Choose on a really bad day?
- From: "Hunold, Ken" <KRH@xxxxxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Thu, 21 Sep 2006 09:53:23 -0400
I try not to weigh in on these issues because it is obvious there is no
simple solution.
In an emergency, most people have been conditioned to use an
old-fashioned, common form of modulation. AM. Sometimes called
"ancient modulation." I spent some time in the Midwest (where they have
a LOT of tornados) and everyone has a battery-operated radio for just
such occurrences. And really, it's more than just a modulation choice.
It's just one component of the system. Think about it. Small portable
radios. Good coverage of the local area. The large size of the
transmission antenna helps foster site-diversity among the provider (the
stations) in case one station gets a direct hit from a tornado (I've
seen it happen.)
Battery-operated televisions are rare (probably rarer than ATSC tuners,
but I'm just being sarcastic here.) Current zoning restrictions favor
multiple stations operating from a common antenna, or ones that are very
close to each other. No site diversity in case there is a major
problem. I live in the New York area, and I've seen it happen. Twice.
In both cases, people flocked to listen to portable AM radios (there's
one in just about every car.) Also during blackouts. Radio stations
are usually designed from the ground up (literally) to operate without
public/private utilities to provide news and information to their
audience.
A lot of DTV stations broadcast a weather subchannel. Call me a cynic,
but I can't believe that it is to inform their audience better than the
station down the street. It's just there for competition and marketing,
or worse.
I mentioned that I live in the New York area. I also work in New York
City. This week, the United Nations is in session. We are being
attacked by a plague of black, four-wheeled porcupines with tinted
windows. Hundreds of them. Judging from the size and shape of these
sticks, domes, and discs, I doubt many of them are receiving TV signals.
I'd also bet that many of them ARE using digital modulation techniques,
probably including COFDM. That's great! It works for their purpose.
Just like COFDM works great for "ENG" in television.
I also know that you shouldn't use your own experiences and assume that
it represents the general population. But I'll break that rule and
share my experience with DTV. At my home, I get fair NTSC reception
over the air. After September 11, 2001 I took down my VHF/UHF antenna,
ordered LIL service from my satellite provider. "Transition to Digital"
accomplished in my house. I also put up a UHF-only antenna for
over-the-air digital television. Now that all of the stations are up
using their DTV facilities, I receive most of the OTA digital services
with this antenna. The ones I don't get (actually two) are due to
co-channel NTSC interference from an adjacent market in one case, and
low-power DTV operation in the other. I also have cable (but no longer
have satellite) so I can get the DTV signals that I cannot get over the
air. Net result, I am happy with the way it works. I also have a
portable DTV receiver that I use with my laptop. It is a
"5th-generation" receiver, and it's the only one I've seen that gets all
of the DTV stations at my desk in the office. I don't have to tell you
what NTSC looks like in my office. If other people want good TV service
in my office building, they have to get cable. Heck, that's why it was
put in in the first place!. Again, the net result is that I am happy
with the way it works.
Would other digital modulation schemes work? I assume it would work in
the office, but I doubt it at home. I live far enough away that I might
not get enough signal from a big stick, and I don't know if someone
would be willing to put up a repeater tower closer to me.
I know it's probably just me, but I wouldn't reach for a TV set in an
emergency (like a tornado.) I would use it in a snowstorm, or to watch
the progress of a hurricane, but if a hurricane or tornado hits, it's
going to be radio for me. I guess what it boils down to is: Do I
really need my TV signal to supply my communications needs "when (I)
need it most?" No. I have a way to get information during those events
from several other sources. What I want my TV service to do is reach me
where I live so I can be entertained and informed the other 99.xx% of
the time, too.
Regards,
Ken Hunold
-----Original Message-----
From: opendtv-bounce@xxxxxxxxxxxxx [mailto:opendtv-bounce@xxxxxxxxxxxxx]
On Behalf Of John Shutt
Sent: Wednesday, September 20, 2006 5:11 PM
To: opendtv@xxxxxxxxxxxxx
Subject: [opendtv] Re: Which Modulation Would You Choose on a really bad
day?
----- Original Message -----
From: "Stephen W. Long" <longsw@xxxxxxxxxxxxxx>
> 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.
Let's hope 8-VSB is receivable. The Department of Homeland Security and
FEMA has bet our safety on it.
http://www.apts.org/news/deas.cfm
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