Over the air TV to stop?

On Sat, 16 Jan 2010 08:11:51 -0500, "Michael A. Terrell"
<(E-Mail Removed)> wrote:

>
> Sigh. Read up on 'The 150 mile rule'. TV frequencies are subject to
>skip, ghosting, signal fade and a lot of other problems. Also there are
>grade 'A' and grade 'B' coverage areas.

You still seem to be living in the analog era with big transmitter
towers :-).

>I got a letter at a TV station
>who's transmitter is near Daytona Beach back in the '80s from a man in
>west Texas reporting that he had a clear signal for a few minutes short
>of eight hours one evening.

I am fully aware of tropospheric ducting an other tropospheric
propagation modes.

The only surprising thing is that the transmitter was on the East cost
of Florida. Typically this kind of ducting occurs only a few meters
above water. Radio amateurs have made contacts up to 1000 km up to 10
GHz with antennas just a few meters above the water front, while
antennas a few meters higher were useless.

Perhaps the transmitted signal had reached an elevation just few
meters above the sea level, when it reached the West cost of Florida,
before being ducted into Texas.

Some broadcasting companies have done quite a lot measurements for
decades to detect such propagation anomalies and the potential for
interference to their services. Practical experience also show that
the interference could be so bad that the intended audience is not
reached.

One might expect that similar propagation anomalies would cause havoc
to cellular phone networks (similar to trying to use a cellular phone
in an aeroplane), but I have never heard of problems due to
tropospheric propagation. Apparently the lower tower heights and the
higher signal levels at the intended service area, will handle most of
these problems.

Paul Keinanen Inscribed thus:

> On Sat, 16 Jan 2010 08:11:51 -0500, "Michael A. Terrell"
> <(E-Mail Removed)> wrote:
>
>>
>> Sigh. Read up on 'The 150 mile rule'. TV frequencies are subject
>> to
>>skip, ghosting, signal fade and a lot of other problems. Also there
>>are grade 'A' and grade 'B' coverage areas.
>
> You still seem to be living in the analog era with big transmitter
> towers :-).
>
>>I got a letter at a TV station
>>who's transmitter is near Daytona Beach back in the '80s from a man in
>>west Texas reporting that he had a clear signal for a few minutes
>>short of eight hours one evening.
>
> I am fully aware of tropospheric ducting an other tropospheric
> propagation modes.
>
> The only surprising thing is that the transmitter was on the East cost
> of Florida. Typically this kind of ducting occurs only a few meters
> above water. Radio amateurs have made contacts up to 1000 km up to 10
> GHz with antennas just a few meters above the water front, while
> antennas a few meters higher were useless.

I can confirm that. I've got confirmed qls of 2000 miles on VHF and
1200 miles on UHF. Winding the tower up caused the signals to get
weaker and disappear. Another local ham 60ft higher than me broke in
to ask who I was talking to, because he couldn't hear the other side.

> Perhaps the transmitted signal had reached an elevation just few
> meters above the sea level, when it reached the West cost of Florida,
> before being ducted into Texas.
>
> Some broadcasting companies have done quite a lot measurements for
> decades to detect such propagation anomalies and the potential for
> interference to their services. Practical experience also show that
> the interference could be so bad that the intended audience is not
> reached.

Dutch VHF television used to be an everyday occurrence here the UK.

> One might expect that similar propagation anomalies would cause havoc
> to cellular phone networks (similar to trying to use a cellular phone
> in an aeroplane), but I have never heard of problems due to
> tropospheric propagation. Apparently the lower tower heights and the
> higher signal levels at the intended service area, will handle most of
> these problems.

--
Best Regards:
Baron.

In article <hilj7a$nhm$(E-Mail Removed)>,
"Charles" <(E-Mail Removed)> wrote:

> "James Goforth" <(E-Mail Removed)> wrote in message
> news:19875-4B493164-(E-Mail Removed)...
> > I have been seeing ads on the TV stating that there's some kind of
> > movement which supposedly threatens to end over-the-air TV broadcasts to
> > the public -- which doesn't make much sense after all the hassle of
> > changing over to Digital broadcasts. What are they talking about?
> > It doesn't elaborate on it, and what is even more strange, it doesn't
> > even have a website to visit for more info.
>
> It's called scrambling for limited resources. The RF spectrum is a limited
> resource. Currently, radio and TV broadcasters (and others) own a large
> chunk of it. Well, ownership can and will change in this brave new world.
> As the Microsofts and the Googles continue to gain more control of the
> economy, they want more resources.
>
> It's not necessarily a bad or evil thing. Actually, wideband Internet
> delivery of content can do much more (a better job in many cases) than
> conventional broadcasting. I see the giant competitors merging in the near
> future, if the Democrats will allow that to happen.

The first problem I have with all of this that US telcos are a national
embarrassment. They state that the FCC has no right to control their
Internet services as a public utility yet any competition with them
unleashes lawsuits for unlawful competition with a public utility.
Until the FCC grows a pair, I'd rather have TV over the air than through
the telcos.

The second problem I have with this is Google. Google doesn't really
give a crap about wireless broadband. Google wants whitespace WiFi
because they're going to solve interference problems using a large
geolocation database that can pinpoint exactly where ever Internet
customer is. I know it sounds too crazy to be true, but search for
"google geolocation service" and you'll see that it's already online.
--
I won't see Google Groups replies because I must filter them as spam