In article ,
Doug Smith W9WI wrote:
I'm a lot more worried about it as a TV engineer and semi-rural
over-the-air TV viewer. In early tests these things weren't very good at
determining whether a channel was unused. I can see that becoming a big
problem in semi-rural areas like this, where people might be using rooftop
antennas to get TV but the Internet devices will probably be on makeshift
indoor aerials.
According to an article in Moble Radio Technology magazine recently,
there's another issue in some areas (about ten major metro areas)
where various public safety agencies have already been authorized to
use the white space in the channel 14-20 range for various types of
public safety communication.
Some of these applications (e.g. video surveillance cameras) are
designed to be "indetectable" while in operation... which makes things
problematic for the proposed free-white-space-detection devices. The
police would be unamused by having their stakeout-surveillance video
feed stomped upon by web-browsing passersby!
The quick solution to this is to forbid the use of free-white-space
devices in this frequency range, in those cities where public safety
operations have already been authorized. This won't necessarily solve
the problem, if (for example) a user of such a device brings it from a
"wide open" city into a city with restrictions, and doesn't realize
that s/he has to change the device's mode to stay legal.
The pro-audio industry is also up in arms over these whitespace
proposals, as they've been depending for years on Part 15 (or similar)
wireless microphones which operate in the unused TV channel
frequencies. Having to face competition for these frequencies from a
whole bunch of non-coordinated new "find a 'free' frequency and camp
on it" devices could cause problems for them, to say the least!
--
Dave Platt AE6EO
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