On Sat, 10 May 2008 09:34:12 -0400 Tam <t-tammaru@[EMAIL PROTECTED]
> wrote:
|
| <phil-news-nospam@[EMAIL PROTECTED]
> wrote in message
| news:g03k3f5fci@[EMAIL PROTECTED]
|> On Sat, 10 May 2008 06:39:09 GMT Wes Newell
<w.newell@[EMAIL PROTECTED]
>
|> wrote:
|>
|> | I've never had cable, but I assume they can set the frequencies to
any
|> | value they want to on there equipment, thus using the same OTA
|> | frequencies. Maybe not for some reason. In any case, 2-13 would
provide
|> | them enough bandwidth to broadcast 60 SD programs using 8vsb. I don't
|> know
|> | how many analog channels basic service provided, but I doubt it was
more
|> | than 60.
|>
|> They could. But there would be more waste as the existing channel slot
|> scheme
|> has them in different places, and fitting in some 8VSB would leave
gaps.
|> If
|> the do just 12 8VSBs and put them on 54-72 MHz, 76-88 MHz, and 174-216
|> MHz,
|> then they are good to go and are only losing about 230 mbps of
capacity.
|>
| I think it is purely a software issue. You should be able to be in cable
| mode and switch the IF output to the 8VSB instead of QAM detector. This
| would get you all cable channels.
For their own STBs, apparently they could program them in advance. I
don't
know if cable systems do this, but in theory a workable design would be to
have one narrowband signal that transmits the system channel layout to the
box. That would avoid timely channel scans.
Or they can upgrade the software in their own boxes to improve on the
scan.
But it would take longer if the boxes have to check both modulations on
all
channels.
The point is, though, if they want to make CECBs work beyond 2-13, they
need
to use the OTA frequencies on at least the 8VSB channels intended for
those
boxes. Say they use OTA channel 14, 15, 16, and 17 for 4 more channels.
That
uses 470-494 MHz. But that means they can't use cable channels 65, 66,
67,
68, and 69. So they lose 5 cable channel slots to do 4 OTA channel slots.
OTOH, if they don't go all the way up to cable channel 125, then they
could
use the high end of OTA channels at 69 and down, until they meet the high
end of what they are doing on cable channels, however many that might be.
But I believe most cable systems seeing a spectrum availability issue are
already up to channel 125.
1. They could just live with the gap and lose a channel.
2. They could move all the QAM channels down 4 MHz. That would be a huge
change in the system.
3. They could reprogram all their boxes. Either that programming needs
to
be exactly aware of what channels are in what mode, or it has to do an
even longer scan to find out.
4. They could limit the 8VSB channels to just 2-13. 12 TV channels is
more
than anyone could ever need, right :-)
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