[opendtv] Re: Interesting Point
- From: Richard Hollandsworth <holl_ands@xxxxxxxxx>
- To: opendtv@xxxxxxxxxxxxx
- Date: Thu, 27 Oct 2005 13:25:58 -0700 (PDT)
Diversity Receivers for DVB-T abound in Europe.
(And are also readily available for NTSC in automobiles.)
But thus far, none have been offered for use with ATSC....why is that???
A diversity antenna system "fills in" most of the deep multipath signal
dropouts and hence is far more effective than buying bigger antennas...or even
stacked antenna systems.
A Diversity Receiver also facilitates connection of multiple antenna systems
pointed in different directions, ensuring that the result is optimized with a
Maximal Ratio Combining (MRC) algorithm in the signal equalizer.
In San Diego, the major networks are located on three widely separated
mountaintops (one in Mexico) with a fourth UPN-HD planned for a fourth location
in Mexico.
/////////////////////////////////
I believe that SFN is one of important features of DVB-T that can improve
coverage over a wide area, including indoors.
What would be interesting is to compare (upcoming?) service reliability tests
of ATSC Single Frequency Networks to those already in use in Europe for DVB-T.
Then we could see how many OTA STB/HDTVs are impacted, given a much wider echo
delay spread.
I would predict that many who get ATSC today, will find that they will need to
revisit their antenna systems (change directions, upgrade for more
directionality, etc.) and possibly upgrade to a 5th or later generation ATSC
receiver.
<holl_ands>
/////////////////////////////////////////////////////////////////////////
"Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx> wrote:
John Shutt wrote:
> Given today's improved diversity reception DVB-T receivers,
> so would I.
First, anyone can implement diversity reception.
Second, this does not affect the max range coverage. It
improves coverage when obstacles exist.
As far as I'm concerned, tests done when 8-VSB receivers
were still using real-only equalizers and crappy ones at
that are OBE. I'd genuinely be interested in new tests,
including also indoor reception at long range. Simply
because if 8-VSB is not demonstrably better than OFDM at
this, then there's no excuse to keep it. If it is better,
then the real tradeoffs in coverage would be very
interesting to see.
I'd like more truth and less religious evangelism, in short.
Bert
---------------------------------
Yahoo! FareChase - Search multiple travel sites in one click.
----------------------------------------------------------------------
You can UNSUBSCRIBE from the OpenDTV list in two ways:
- Using the UNSUBSCRIBE command in your user configuration settings at
FreeLists.org
- By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word
unsubscribe in the subject line.
Other related posts: