FCC: DTV Re-Transition To VHF Bands Now Being Touted - Page 2 - Canadian TV, Computing and Home Theatre Forums

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post #16 of 58 (permalink) Old 2010-11-07, 04:17 PM
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The "roll over" rate of technologies in the wireless mobile world is a good example of how flexible consumers can be when the "next best thing" contains direct benefits to them. Is anyone demanding that we stop at 3G? Of course not. 4G here we come! So, why should TV system changes and updates be any different?

As I've said, if an OTA channel re-transition is to take place it is an opportunity to give consumers better choices than ever, provided that backwards compatibility is maintained during the product overlap timeframe. This could be time well spent to make DTV better than ever, incorporating a lot of lessons learned with new capabilities such as MPEG4, 1080p, TrueHD 7.1, and other features. The ATSC standard has some ugly kludges in it (i.e. PSIP) that would benefit from a revisit/replacement.

A comment I've often made (as with many other people here and elsewhere) is that the mobile/wireless operators need to improve their use of bandwidth. Fair is fair, so the same should apply to DTV. So, as long as broadcasters aren't left having to pay for a re-transition (I agree with GeorgeMx's view on that) then this would be an ideal time to fold in a big improvement in DTV.
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post #17 of 58 (permalink) Old 2010-11-10, 01:05 AM
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This topic brings up a very good question.
IF we moved to MPEG4 to fit more data in a smaller space, would existing tuners be compatible?
I mean, MPEG4's been in the ATSC spec for a couple years now.. would it not stand to reason that any tuner built since MPEG4 was added to the spec, be able to decode MPEG4?

If so, that only eliminates the very early adopters.
Whom, by the time we actually moved to mpeg4, will probably have replaced those devices (unless we're talking in the very near future).

And if this did happen, we'd probably have a few years' overlap just as we do now with analog-digital.
Only, maybe a UHF channel with mpeg2, and a VHF with mpeg4.
Or perhaps main+subchannel on the same physical channel, one mpeg2, one mpeg4.

This assumes it would require new hardware, of course.
It could be a simple firmware-only update, which means there's no issue at all!
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post #18 of 58 (permalink) Old 2010-11-10, 10:36 AM
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I am not going to say for sure, but I would say quite a bit of gear is MPEG2 only.

Any PC based DVR, satellite based DVR which supports MPEG4 for satellite, and any HD TiVo model, can in theory support ATSC MPEG 4, if the modulation scheme stays the same.
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post #19 of 58 (permalink) Old 2010-11-10, 11:36 AM
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Originally Posted by recneps77 View Post
IF we moved to MPEG4 to fit more data in a smaller space, would existing tuners be compatible?
AFAIK. Most if not all TVs and STBs will not decode MPEG4. As classicsat said, some satellite boxes and PC based PVRs might be able to do it though as they may already have MPEG4 decoder chips or else the software can be upgraded to do MPEG4 deciding (if the CPU is fast enough), though software decoding often isn't as good as hardware decoding.

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would it not stand to reason that any tuner built since MPEG4 was added to the spec, be able to decode MPEG4?
No. Unless they are mandated to support it or they see a marketing benefit for adding it, manufacturers won't spend money to add new features.
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post #20 of 58 (permalink) Old 2010-11-10, 06:03 PM
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I understand the 'bare minimum' piece
My point on that second part was more along the lines of "in order to call it an ATSC-compliant product, would it not be required to meet all aspects of the ATSC standard?"

Otherwise, what's the point of a standard if anyone can pick any piece of it that they want and still use the name?
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post #21 of 58 (permalink) Old 2010-11-10, 06:38 PM
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Quote:
Originally Posted by recneps77 View Post
I understand the 'bare minimum' piece
My point on that second part was more along the lines of "in order to call it an ATSC-compliant product, would it not be required to meet all aspects of the ATSC standard?"

Otherwise, what's the point of a standard if anyone can pick any piece of it that they want and still use the name?
For example, I don't think there is a rule that says you couldn't build a USB 1.0 device today.
Why can't someone continue to implement an older ATSC standard?
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post #22 of 58 (permalink) Old 2010-11-10, 10:54 PM
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Otherwise, what's the point
That sort of thing is quite common. Look at all the frame resolutions and rates ATSC includes and try to find a TV that supports them all.
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post #23 of 58 (permalink) Old 2010-11-11, 03:56 AM
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MPEG4 was approved as an ATSC standard component long after much of today's broadcaster and consumer equipment had shipped. I should have clarified that. Go back and read through this thread from that perspective. Would hardware and software improvements or replacements be necessary? Yes, and that is my point. Look at the Mobile world and the churn is vastly more rapid, yet consumers still buy the latest, greatest.

My question is why should that not be a possibility if it means having a continuously improving DTV capability?
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post #24 of 58 (permalink) Old 2010-11-11, 10:14 AM
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ATSC-M/H is an OPTIONAL feature in the ATSC specs.

H.264/MPEG4 was added to ATSC specs as part of the ATSC-M/H (Mobile/Handheld) upgrade.
It will be in many of the new ATSC Decoder chips (or H.264 in the attached device)....although
a DTV manufacturer will still have to CHOOSE whether they want to pay the extra Royalty fees
and implementation costs, based on how they perceive "consumer demand", just as they will
decide whether they want to implement Internet or internal storage (or whatever) features in
a particular model. Which is why we'll see ATSC-M/H primarily in mobile devices to begin with.

PS: EVERY ONE of the 18 ATSC frame rates & resolutions has been implemented in EVERY ONE
of the ATSC Decoder chips produced over the past 7+ years. And most chips even include
16VSB modulation that lost out to QAM64/128 on U.S. cable systems.

BTW: Fol. IEEE paper describes how the large number of resolution & frame rates stipulated
in ATSC A/53E, Table A3 are reduced to the frequently cited list of only 18 ATSC formats:
http://ieeexplore.ieee.org/xpl/freea...number=1566624
List of 18 ATSC formats:
http://www.hdtvprimer.com/ISSUES/what_is_ATSC.html
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post #25 of 58 (permalink) Old 2010-11-11, 11:19 AM
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That IEEE table corresponds to the first table here. What about the 2nd table that's for 50Hz systems? My Sharp Aquos can handle PAL-N (and PAL-M), but I have no idea about other 50 Hz formats. There are many people who are interested in 50 Hz video sources, particularly immigrants who want to see shows from their home country.
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post #26 of 58 (permalink) Old 2010-11-11, 11:24 AM
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The 50Hz capability was considered necessary as a way to allow ATSC to be exported to other parts of the world. As DVB-T became the defacto world standard (amongst a few others) the ATSC standard did not take off elsewhere.

Just a reminder that we're keeping this thread focused on the discussions in the U.S. about a possible re-transition of channels to the VHF bands, and reasons why this may or may not be a good thing.
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post #27 of 58 (permalink) Old 2010-11-11, 12:19 PM
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Although I wouldn't rule out receiving European (Icelandic?) PAL and/or DVB-T broadcasts from
Europe on some of the Lo-VHF channels if you are located in far-East Canada or Maine, it's very
unlikely....ditto for receiving South American (perhaps some Caribbean islands?) broadcasts in
the southern U.S. states, esp. in RURAL locations via Tropo Duct or other modes of propagation:
http://en.wikipedia.org/wiki/TV-FM_DX
http://home.iprimus.com.au/toddemslie/dx.html
http://tripatlas.com/TV-FM_DX
Note that many TV-DX reports are for hearing the audio FM carrier, a few actually see Video.....

Sporatic-E long-range VHF propagation mode is sometimes available (Todd is in Australia):
http://home.iprimus.com.au/toddemsli...radic%20E.html
http://home.iprimus.com.au/toddemslie/highbandspe.html

And there is UHF Moon Bounce propagation mode for extreme range fanatics:
http://home.iprimus.com.au/toddemsli...-eme-tvdx.html

Immigrants in North America mostly can receive 50 Hz formats via either DVD or C-Band Satellite.
There are many DVD players that convert PAL discs for NTSC output, but only a few that are
"Region Free", rather than "Region 1" for North America ONLY. [Google for some hacks....]

I presume PAL on SAT requires a PAL compatible TV unless conversion is provided by SAT Receiver.
Of course, you would need to be line-of-sight to desired SAT: http://www.dishpointer.com/
C-Band programs for each satellite can be found at: www.lyngsat.com
Unfortunately, it isn't easy to determine whether the "A" (Analog) symbol means NTSC or PAL,
so consider where the material originated....

As Stampeder sez, ATSC A/63 is a dead standard....Google search does not reveal implementation
by any of the chip manufacturers....nor did I find A/63 in the several old spec sheets I looked at....

BTW: Several years ago, while stationed in Italy, my son-in-law bought an HD-RPTV which supported
both NTSC (on-base AFRTS) and PAL (local Italian broadcasts). But since the military on-base systems
have not yet been upgraded for HD, there is no market for a multi-format HDTV (NTSC, QAM & DVB-T).

AFRTS (Armed Forces Radio Television Service) employs Satellites, on-base cable systems and (in a few
foreign countries) On-Air NTSC transmitters to provide television programming to U.S. service families:
http://afrts.dodmedia.osd.mil/
List of FM and NTSC On-Air transmitters in foreign countries:
http://afrts.dodmedia.osd.mil/facts/7.pdf
I wouldn't be surprised if they convert OTA from NTSC to ATSC sometime in the next several years,
but FIRST they have to convert SAT distribution system to HD...beginning in 2012:
http://myafn.dodmedia.osd.mil/PrintV...aspx%3fb%3d872

So other than a possible future AFRTS ATSC transmitter in a foreign country, where would anyone
ever need a dual format ATSC & DVB-T HDTV????? The market must be vanishingly small.....
It would make more sense to use an external DVB-T Tuner box with an ATSC HDTV (or vice versa).
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post #28 of 58 (permalink) Old 2010-11-11, 10:00 PM
 
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Quote:
Originally Posted by stampeder View Post
...Just a reminder that we're keeping this thread focused on the discussions in the U.S. about a possible re-transition of channels to the VHF bands, and reasons why this may or may not be a good thing.
We have been down an MPEG4 rat hole.

I think that a transition from UHF to high VHF is feasible but not combined with a change to the ATSC standard. Upgraded OTA technology that caused consumers to require an adaptor or new TV set would damage confidence in OTA reception. In my opinion, only a new encrypted service with an external receiver could incorporate different technology than standard ATSC.

I believe that moving to VHF would be possible with better use of existing technology. For example, transmitting antennas have gain because the RF energy is concentrated in the vertical plane. Stated differently, the amount of energy reaching the ground close to the transmitter is sacrificed to get more energy on the horizon. The problem with VHF seems to be building penetration close to the transmitter so using lower gain antennas would put more power on the ground. The higher the antenna, the worse the problem. A combination of more transmitter power, lower gain and suitable downtilting should get both distance and building penetration from the same transmitter site.

Another solution to the VHF problem is on-frequency repeaters. Significant research has been done in Ottawa on this technique as a means of filling coverage gaps. Repeaters increase capital and operating costs but if the value of the UHF spectrum is high enough, the wireless companies should be prepared to pay.

You might argue that shifting from UHF to VHF has problems similar to changing technology as some customers will need to add VHF antennas. In some locations, the UHF antenna will capture enough signal to provide reception on hi-VHF channels. Further, there is no reason why the most highly viewed channels should be transitioned. The minimally disruptive approach would be moving the least viewed channels. To provide an incentive, stations transitioning to high VHF channels might gain broader coverage to compensate for the disruption. Part of the transition cost might be offering VHF antennas at low prices or even free using funds from the wireless companies. Antennas have been given away by broadcasters in the past to overcome reception problems.
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post #29 of 58 (permalink) Old 2010-11-11, 11:18 PM
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That still won't change the fact that VHF-lo antennas are a PITA for consumers and VHF-lo is too susceptible to interference from tropo interference. IMHO, a lot could be done with fewer UHF channels by using better channel assignments. That might cause problems in very dense markets though. I also have no doubt that UHF and higher frequencies could be clawed back more easily from uses other than TV.

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post #30 of 58 (permalink) Old 2010-11-11, 11:27 PM
 
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That was going to be my main concern as well. All the consumers, and broadcasters who have already bought Uhf antennas, would once again need to upgrade. Could get quite costly. The other thing is there is only 12 Vhf channels. Some markets have more than 12 stations, so there would have to be a lot of sub channels created. Also what about the interference factor that seems to plague some vhf channels. Would they be able to make DTV on VHF less prone to interference, which is why as I understand it, they donot recommend lo VHF for DTV.
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