[opendtv] Re: How About Portable ATSC Receivers?
- From: "Manfredi, Albert E" <albert.e.manfredi@xxxxxxxxxx>
- To: "OpenDTV (E-mail)" <opendtv@xxxxxxxxxxxxx>
- Date: Thu, 31 Mar 2005 17:31:58 -0500
John Shutt wrote:
> Play with an ATSC STB, then you can lecture me on the
> ease of reception afforded by ATSC vs. NTSC.
How does this change Jay's brother's experience, exactly?
Or Mark's with the prototype box? Why would a test
with your 2nd gen box convince me of anything?
> P.S. If the United States were 90% wired (and/or DBS),
> and Australia were 0% wired, that would still make a
> market of 10 million US TVHHs, and only 7 million AU
> TVHHs.
>
> Where is your logic?
It's simple. US OTA users, just like those in Berlin, are
and were satisfied with their analog channels. They had
some 12 channels of analog available in Berlin before the
switch, and that was sufficient for most Berliner OTA
users. I'd say the Berlin market was smaller than
Australia, yet when the date was set, boxes appeared at
prices that dropped rapidly. But not until then.
Here in the US, especially as long as broadcasters don't
develop attractive multicast offerings, OTA users have no
particular motivation to go DTT. Added cost, no extra
choice. And never mind hassle with iffy receivers.
> Mine says every manufacturer that has tried to make an
> ATSC box has found out they are difficult and expensive
> to make, don't work very well, and there is too high of
> a return rate.
That's because your mind was made up 6 years ago, and
facts don't make any difference. The LG prototype was
small in size, not especially costly to produce according
to them, and seemed to work extremely well indoors. The
cost issues mentioned by XXXX didn't even have anything
to do with modulation type. Yet, your mind is made up.
And returns of 2nd or 3rd generation boxes would not
apply any longer, just as ATSC-COFDM comparisons from
1999 wouldn't apply any longer, if known state of the
art techniques were use in production.
> If there is no demand for ATSC, then let's switch to
> DVB-T and create some demand.
Will Jay's brother continue to be able to receive
stations 45 and 52 miles distant, with rabbit ears
indoors? Let's do some SWAG numbers.
The Berlin coverage contour for Channel 44 was 12 to
14 miles with indoor antenna, with a two-tower 170 KW
ERP per tower SFN, using 16-QAM and 2/3 FEC
(2.1 b/s/Hz).
Let's say 14 miles, and let's use the most benign losses
with distance, i.e. free space loss only.
The difference between 14 and 52 miles in free space is
11.5 dB of extra loss, at 600 MHz.
So to scale up the Berlin Channel 44 transmitter to
reach 52 miles, you'd have to go from 170 KW ERP to
about 2.4 MW ERP. And yet, at 3.3 b/s/Hz, Jay's brother
is receiving 1 MW ERP stations.
Doesn't that intrigue you at all? That's what keeps me
interested.
Bert
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