[opendtv] Re: Monitoring Signals With ATSC USB Tuners
- From: "John Shutt" <shuttj@xxxxxxxxx>
- To: <opendtv@xxxxxxxxxxxxx>
- Date: Thu, 30 Sep 2010 10:12:43 -0400
Good points, Ken.
See inline snarks:
----- Original Message -----
From: "Hunold, Ken" <KRH@xxxxxxxxx>
I don't want to get into a discussion of what M/H TV would be (or should
be) used for, but my guess is that it will not be just to replicate the
"main" feed more robustly. Maybe just the audio, but I digress/linger
here.
My guess is the opposite, that the M/H feed will be a simulcast of the main
channel (XX.1) of the station. The additional subchannels may not be
duplicated in the M/H feed, simply because in order to carve out enough bits
out of the main channel to carry that many M/H channels, you've lost the
bits necessary for the multiple channels in the main bitstream.
If we had DVB-T here in the US, I bet I wouldn't have OTA television at
my house (40-50 miles from the New York canyons.) Certainly not from at
least three markets, as I do now with "big stick" ATSC transmission. It
would work at my desk in Midtown (big deal, I don't watch TV there if I
can avoid it, but with current receivers, it even works there.) I don't
see stations in a position to build a repeater system to serve "rural"
viewers. One of the network O&O station has a permit for a repeater,
but hasn't built it yet. It would seem prohibitively expensive to
expand coverage by even 10 miles all around the coverage area.
Many, if not most, stations have a direct feed to their largest cable
operators, so that the majority of a station's viewers still have a picture
if the main transmitter goes out.
Given DVB-T's reception in the UK with such miniscule power levels, and the
proven far field performance of DVB-T compared to ATSC during the Sinclair
Baltimore Summer of Love in 1999, I doubt that your reception would be any
worse than it is today, and probably better.
Back in the day, the head end for my local cable company had their
antennas even farther away from town than I do. It's a moot point now
because it was bought by an MSO and is probably fed by some OC-whatever
link from their main system.
MSO antennas have a height advantage over your home setup, and are also
usually tuned yagis, cut for a specific channel. No worries there.
COFDM makes sense for some applications, like ENG operations. It would
probably work great on something like the NYC Marathon, but last time I
checked, it looked like they were still using analog. (At least the
video from the motorcycles broke up in the same places it did when they
were using analog FM.) Maybe that will change this year.
Now that the Sprint/Nextel migration of the 2 GHz band is complete, you
should see macroblocking this year.
I don't think broadcasters are planning to use M/H to improve robustness
on their main feeds. Cable filled that "niche" decades ago, and has
moved on to deliver other things. I expect broadcasters will also do
"other things" with their M/H systems.
What sort of other things would justify the expense of the new exciters
required, and trading off the main channel bitrate payload, which is already
stretched to the limit due to our 6 MHz wide channels?
One last thing: Content downloaded, side loaded, or broadcast to a
phone or other mobile device doesn't *have* to be watched on that
device. I've seen 720p video with 5.1-channel audio. It could
happen... ;)
I've seen new smartphones with HDMI output jacks, as well as other handheld
devices. Better for sharing home movies from that HD Flip Camera than
viewing the latest episode of Weeds, but hey...
John
P.S., Bob Miller's Viacel website is no more, but I did save his video.
Maybe one day I should edit it down and post it on YouTube. I'll ask Bob
for his permission.
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