In article ,
Jaques d'Alltrades wrote:
The message
from martin contains these words:

All UK analogue TV transmission will be phased out between 2007 and
2012, enabling transmitter power to be increased, which should produce
better/stronger digital signal. You may get it then.

It's not so simple. Digital TV needs line of site for good reception.

Line of what?

Line of site. If you don't line up your aerial correctly with the site
of the transmitter, you will not get good reception. Really!

Whether a signal requires a clear line of sight between antennae depends
on frequency, not mode of transmission.

TV signals will bounce from solid objects at their frequency, whereas at
higher frequencies they tend to be absorbed. Certainly at frequencies
approaching a gigahertz even a tree in leaf will block a signal, but at
TV frequencies, they won't.

And, at MUCH higher frequencies, even houses become transparent :-)

Well, ignoring that lunacy, it is too much of a simplification to
say that signals bounce of solid objects. The wavelengths are such
that there is considerable interference, which produces weird effects.

If a even weak analogue signal can be received, a digital one of the
same strength is likely to be processed much better.

Er, no. If the digital signal isn't good enough for its error
correction to work, you will get effectively nothing. You will
continue to see and hear SOMETHING for even lower quality analogue
signals, though few people will want to.

I haven't looked into the digital signal technology in detail, but
it is very similar to tape recording technology as far as encoding
goes. And digital recording needs EITHER a significantly higher
bandwidth OR a significantly better signal to deliver the same
quality of analogue signal back.

This is because you are starting and ending with analogue; when you
are starting and ending with digital (as in computer data), then
transmitting in digital is better. You can only lose information
by converting between the two, not gain it.


Regards,
Nick Maclaren.