[BC] Grand Alliance

[Davis, Jack L. KTXL]

Message: 9
Date: Tue, 18 Oct 2005 11:46:09 -0400
From: Robert Meuser <Robertm at broadcast.net>
Subject: Re: [BC] HD Radio multicasting bandwidth
To: Broadcast Radio Mailing List <broadcast at radiolists.net>
Message-ID: <435518C1.1010207 at broadcast.net>
Content-Type: text/plain; charset=ISO-8859-1; format=flowed



DANA PUOPOLO wrote:

> Look at what the HDTV 'Grand Alliance' did. Because they refused to 
> wait SIX MONTHS, we got saddled with 8 VSB HDTV, which as about a 
> quarter as robust as COFDM, the system the rest of the world adopted.
> 
> Because they couldn't wait, our HDTV system is INTERLACED, instead of 
> being progressive scanned (which would have made it compatible with 
> computer video).
> 

Dana

you are sooo wrong. The 8 vsb problem  is now very well solved on the
receiver 
side. I live in an RF cavern and can receive all local DTV signals with an 
Indoor antenna. My reception far exceeds analog on the same antenna.

  As for interlaced, again you must be smoking something as 720  P and 480 P
are 
part of the spec and are part of what I watch daily.

  As for quality 1080i blows the ass off the competition. We were discussing

this while I was on speaker phone with an ABC tech ( they are 720 P) he over

heard our conversation and added the "yes our video sucks it is only 720P"


Please research your comments before blathering.

R

8VSB while not being perfect was not a bad choice.  COFDM would require much
more transmitter power for equivalent coverage and the only real advantage
was mobile operation.  Also at the time COFDM had never been used in a 6 MHz
wide channel!  The new generation 8VSB decoder chips really make this a moot
point as they decode very well in a multi-path environment.

The progressive and interlaced argument is also very program dependant.  IF
you want to transmit static or slow moving pictures 1080i is a better
choice.  However if you are transmitting scenes with a lot of movement 720p
is a better choice.  Fox ESPN and ABC chose 720p because of the sports
coverage and the lack of interfiled movement.  NBC, PBS and CBS chose 1080i
for cinematic effect.  Who is right?  They both are!  

Here in Sacramento the PBS station has chosen 720p because they do
multicasting and 720p is a bit more efficient for a given bit rate.  I work
at a station where we switched from 480p to 1080i and then to 720p and we
did get calls when we dropped 480p but non when we switched from 1080i to
720p.  

There is now an "enhanced 8VSB" compatible upgrade in progress that will
narrow the gap even more.  I have invited people over to my home to look at
HDTV and the biggest change an average viewer notices is the 16:9 aspect
ratio, not interlaced or progressive scan.  Sure there are those with the
"calibrated" eyeballs that claim one is better than the other but all Joe
Sixpack notices is "hey this looks good"!

The only real shame is that the FCC did not utilize the digital conversion
to modernize the EAS system.  There is plenty of overhead to make EAS work
down to the zip code level and enhance the complete system.  It could even
have been made to turn the TV set or the radio on in the event of an
activation.  Too bad they missed the boat! 

Jack Davis
K6YC & Fox Guy