On Sun, 29 Jun 2008 03:24:59 -0400, Rick T wrote:
However, the analog turn-off will vacate most of TV Ch 2-6,
and most of 7-13. This is the truly valuable channel space,
and will be fought over tenaciously. (174-216 MHz)

There will be 40 full-power digital TV stations remaining in channels 2-6
,
not to mention low-power and Class A stations. There has been some talk
of expanding FM radio broadcasting into this band but I don't think it's
very likely.

This band isn't very appealing to other services, because of the large
antennas necessary for effective operation and the prevalence of noise an
d
interference.

Channels 7-13 are solidly TV territory and will not be going to other
services. There will be 452 full-power digital TV stations on these
channels post-transition, and again some number of low-power and Class A
stations. Most TV stations that had the option of running their permanen
t
digital operation in channels 7-13 chose to do so, even if it meant
obsoleting a perfectly good UHF transmitter/antenna. Coverage is better
for a given amount of power than on UHF, and transmitters are more
efficient. (i.e., lower utility bills)

is also a proposal to allow devices to selectively "seek"
out vacant channels in any given locality to use for low
power applications, without interfering with television.
This works OK with digital TV channels which may be
adjacent, but the problem is that analog LPTV and translator
stations are being allowed to stay on the air indefinitely,
which means that adjacent channels with strange digital
signals filling the bandwidth could spill over causing
interference to an analog TV signal.

"...works OK with digital TV channels which may be adjacent..." is under
dispute, with some engineers arguing otherwise. Especially given the
potentially high U/D (undesirable-to-desirable) signal strength ratios.
In an FCC test earlier this year, they also found the devices did a
*really poor* job of detecting which channels were vacant!
(understandable as these devices are likely to have far poorer antennas
than are commonly used on TV sets, especially in the more rural areas
where the TV signals are weaker and larger antennas are more likely to be
in use)

Analog low-power stations do not have a current deadline for digital
conversion. However, the FCC has announced that there *will be* a
deadline. I doubt it will be more than two years into the future. (and
even if it they do get a lot more time, I think many are going to find
themselves forced to convert as fewer viewers are willing to deal with
analog signals)

The odds of the FCC "giving" any of this spectrum to hams, or other
so-called "citizens" uses are slim since the FCC is mandated by Congres
s
to auction off all non-public-safety spectrum recovered from other
services.

Very true.