Ed's View - UHDTV - See It Soon?

[Ed Milbourn]

Hidden in the backwater of all the 3D hoopla at CES 2010 was the Panasonic 152" Viera Plasma 4K (4096 x 2160) display that has been showcased for the last couple of years. Arguably, the big Viera display was the most striking TV image at the show. There may have been other such Ultra High Definition TV (UHDTV) direct view displays at the LVCC complex this year, but I didn't see them. But NHD's idea of UHDTV promises to be even better!

From the start of serious HDTV research in the late 1970's, Japan's NHK has been "pushing the envelope" of ever increasing television picture resolution – not just related to displays, but...

[url=http://www.hdtvmagazine.com/columns/2010/03/eds_view_uhdtv_see_it_soon.php]Read Column[/url]

[BobDiaz]

I've seen the UHDTV demo at a past NAB show. OK, the high resolution is impressive, BUT at what cost? The first problem is bandwidth; there are so many pixels that even with MPEG-4 H.264 compression, the demo had to be 24P. So we gain a lot of pixels, but lose on the frame rate.

Another issue is "DOC-26935A1.pdf" do a search for it with Google. This plan from the FCC is pushing to drop the number of broadcast channels down to just 30. Remember there has to be at least one blank channel between each active channel, so at best an area might have 10 to 15 channels. How will they deal with the higher bit rate? It this going to be an option for only pay services?

Given the major upgrade costs that the TV stations have had to go through to upgrade to HDTV, I can see them willing to pay even more to upgrade again.

On the other hand, if this is just something for the digital cinema, well it might fly.... or not...



Bob Diaz

[akirby]

Remember there has to be at least one blank channel between each active channel, so at best an area might have 10 to 15 channels.

Are you sure about that? I'm pretty sure we had WXIA in Atlanta using NTSC channel 11 and ATSC channel 10 simultaneously - for at least 8 years.

[BobDiaz]

I was talking about digital channels.

Also, be careful, the number of the channel may not be the frequency of the channel.

See: http://www.tvfool.com/?option=com_wrapper&Itemid=29


Bob Diaz

[akirby]

These were physical channels, not virtual. WXIA channel 11 analog was on channel 11 and WXIA Digital 11-1 and 11-2 were broadcast on channel 10. I know it was channel 10 because it was the only VHF ATSC station in Atlanta and there were many conversations about how to pick it up with a CM4228 UHF antenna (it works BTW as long as you tie the grids together).

There is no difference in the physical reception - a VHF signal is a VHF signal whether it carries NTSC or ATSC. That's why 50 yr old antennas still work just fine.

Think about it - if you really couldn't do adjacent channels then why not just widen the bands and only have half the channels? Why have twice as many channels if you can only use half of them?

[BobDiaz]

In the case of the Analog to Digital switchover, yes both Analog and Digital Channels were placed next to each other. In many cases, there just weren't enough open spaces to do both Analog and Digital TV with every other channel spacing. Because the two systems were very different, the risk of interference was reduced.

I want to point out that the every other channel rule is still going to be followed, because IF all 30 channels were being used by a major city, all surrounding cities would not be able to broadcast on ANY channel because they would be on the same frequency. This would be a a case of 100% interference.

Try to picture a checkerboard where the dark square represents the major city and the white squares around this major city are other broadcast areas. (Think of locations like LA, Riverside, Santa Barbara, and San Diego) too far to always receive the signal from the other city, but too close to avoid massive interference if they broadcast on the same frequency.

In the case of Southern California, Santa Barbara, and San Diego could be on the same frequencies, because the distance is long enough, but frequencies used by LA can't be used in Riverside, plus Santa Barbara, and San Diego can't use them either.

[akirby]

That was a problem with NTSC but not with ATSC. With ATSC you can assign adjacent channels with no problems. e.g.

San Diego ch 18-19
San Francisco ch 38-39 and 29-30
Philadelphia ch 34-35

In some cases there are even 3 channels in a row if you add in a close surrounding city.

Doesn't look like every other channel to me, even in the same city.

[BobDiaz]

There's still the problem that if LA takes a channel, San Diego can't use the same frequency, because one WILL interfere with the other. LA can't take all 30 channels unless everywhere from Santa Barbara to San Diego has zero channels.

The number of digital channels (not sub-channels) within 30 miles of the LA area is 28. IF the number of TV channels is going to be reduced to just 30 (See FCC Document DOC-296935A1.pdf), how will we ever fit all of that AND the UDHD Signals too?

http://www.tvfool.com/?option=com_wrapp ... a353e356a3


Bob Diaz

[akirby]

You could always use SD multicasting and put 4 stations on one physical channel. I'm sure all 30 aren't doing full HD resolutions.

But I'm having a hard time figuring out how that many stations could survive in the first place.

[BobDiaz]

According to my TV after doing a scan, there are a total of 80 digital sub-channels in the LA area. You are correct, the 28 digital stations aren't all doing HD. Going in order to the channel number on my TV:

2 - CBS is HD
4 - NBC is HD
5 - KTLA is HD
7 - ABC is HD
9 - KCAL is HD
11- FOX is HD
13 - KCOP is HD
22 - KWHY is HD
24 - KVCR (Riverside) is HD
28 - KCET PBS is HD
34 - KMEX is HD
50 - KOCE (Orange County) is HD
52 - KVEA is HD

That's 13 stations now doing HD and very likely in the future, others will upgrade to HD. The idea of pushing all TV channels to just 30 channels might work in less populated areas, but it just won't work in major cities like LA. Add to that Mobil-DTV and even UDHD and there's just no way to fit it all in.


Bob Diaz