[opendtv] Re: 20050627 Mark's Monday Memo
- From: "John Willkie" <JohnWillkie@xxxxxxxxxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Fri, 1 Jul 2005 01:11:31 -0700
Frank
I'm suprised about your assertion re far-field. There are members of this
list who routinely send a single ATSC hop -- to serve translators -- that
are several hundreds of miles in length. One is doing this every day in
Arizona, on a station that you routinely watch -- assuming you watch PBS.
There are NTSC hops of more than 225 miles, with the termination point in
Arizona.
Is there a COFDM hop in existence that exceeds 60 miles? I'd be interested
in hearing about those long COFDM hops in Australia. I concede an obvious
advantage with COFDM in close in situations "2 miles without an ENG truck"
is an almost common observation.
But, weren't the Sinclair tests somewhat dispositive of this particular --
far field -- issue?
While were at it, does anybody have contemporaneously captured transport
streams from the Sinclair tests? I'm very interested in testing the MPEG-2
streams for internal consistency and looking into the transmitted metadata.
John Willkie
----- Original Message -----
From: "Eory Frank-p22212" <Frank.Eory@xxxxxxxxxxxxx>
To: <opendtv@xxxxxxxxxxxxx>
Sent: Thursday, June 30, 2005 1:54 AM
Subject: [opendtv] Re: 20050627 Mark's Monday Memo
> Bert wrote:
>
>
> >Nick Kocsis wrote:
>
>
>
> >> But it bothers me that I have read statements on the
>
> >> Schubin tests that even the best of the ATSC 5th
>
> >> generation receivers of today cannot match the
>
> >> performance of DVB-T receivers that were already
>
> >> available in 1999.
>
>
>
> >Bah. I'm not too concerned about that, for these
>
> >reasons:
>
>
>
> >1. Those statements are off the cuff, more emotional
>
> >outburst than carefully tested facts.
>
>
>
> I think you mean that those statements are based on observations &
informal tests, rather than the Zenith/ATSC/FCC specified 30 foot mast
measurements with a properly designed geographic grid and careful
elimination of "problem" test locations within said grid.
>
>
>
>
>
> >2. I find it not only possible but probable that COFDM
>
> >will be better than 8-VSB is some scenarios, now and
>
> >in the future. But the opposite is also going to be
>
> >true, now and in the future, in other instances. The
>
> >two schemes will never perform identically in all
>
> >situations. 8-VSB will do better in long range
>
> >reception, all else being equal, for unarguable
>
> >physical reasons.
>
>
>
> I'm still waiting for a data point - just ONE unbiased data point - that
shows a long range reception advantage of 8-VSB over COFDM. Enough years
have passed, you would think SOMEBODY would have done an honest A/B
comparative test that shows a statistically significant difference in the
far field. I mean a genuinely HONEST test. Not like the ones we saw several
years ago, which weren't worth the paper they were printed on.
>
>
>
> >3. 8-VSB reception can only be improved over time,
>
> >since it depends on clever signal processing. So the
>
> >times it will show an advantage over COFDM can only
>
> >become more frequent rather than less frequent.
>
>
>
> Clever signal processing can be applied to any receiver if cost & power
are don't-cares. Precisely why there will never be a practical portable
8-VSB receiver. Your earlier example of portable Pentium laptops was well on
the mark. Sure we have portable laptops, and some of them even get more than
2 hours of battery life. But they don't compare well in size, power or
battery life with simple transistor radios. The portable DVB-H receiver vs.
portable 8-VSB receiver is exactly THAT kind of comparison - a laptop vs. a
transistor radio.
>
>
>
> >4. Even as far back as 2000, in the Hong Kong tests,
>
> >8-VSB and COFDM both performed equally well in their
>
> >battery of stationary tests. This included indoor and
>
> >outdoor reception (but no mobile testing for 8-VSB).
>
> >So if I were to base all by beliefs on the carefully
>
> >conducted Hong Kong tests, rather than emotional
>
> >outbursts, I would conclude that already 5 years ago
>
> >the system performed just fine.
>
>
>
> Keep drinking the kool aid Bert. If 8-VSB did so well in the Hong Kong
tests, why did that government choose DVB-T?
>
>
>
> >I *realize* that would be hiding my head in the sand.
>
> >I'm just pointing out that one shouldn't consider
>
> >just one data point in such comparisons, especially
>
> >if that data point is unsubstantiated.
>
>
>
> I agree completely. There are now SOOO many data points that repeatedly
demonstrate the overwhelming superiority of one system over the other, that
there is no longer a reason to debate this subject. The profit-minded
sensible business folks have moved on, while the zealots continue to promise
perpetual motion machines and "cold fusion" in the hopes that they can
profit from a government mandated multi-billion dollar rape of American
consumers. Some of those consumers will come to realize that the technology
does not live up to the reliability that is expected from "wireless" these
days. But most will not, because most will never even try to use an antenna
and will never learn just how broken the technology and the network design
really is. They will happily continue watching cable & DBS, and will
eventually get over their grumbling about paying $200 or more for some bs
"feature" that the US government made them pay for when they bought a new TV
set.
>
>
>
> -- Frank
>
>
>
>
>
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