On Mon, 12 Jan 2004 09:24:53 -0000, "Bob Mannix"
wrote:

My Freeview set up also works perfectly. I didn't expect it to, as the
aerial (roof) cable is rather manky with some holes in it (!). I was quite
happy that it might not work but knew I had a strong signal, so I tried it.
It has never failed or dropped signal and the quality is always excellent.
We also have a TV up in the loft conversion, which I use with a cheap multi
element aerial in the loft. The signal here is not very good. Here the
Freeview box struggles and the signal drops out occasionally.

I would agree with Niall that signal strength is the most important factor
and that, although one should not expect a Freeview box to work with the
existing aerial/cable set up, if a strong signal exists, it's worth a try.

With digital TV, the error rate is the most important thing. If the
signal is strong, so can locally reflected signals and these, along
with interference pickup, all result in data errors seen at the
receiver. Discontinuities in cables and poor connectors can lead
to signal reflections in the cable and that will also lead to errors.

Signal strength is also important so that the receiver can
differentiate the data correctly, but once the required threshold is
exceeded, unlike analogue this does not necessarily result in good
reception.

To a point, the transmission system and the receiver can handle and
correct the errors, but they can lead to unpredictable results.

This is not to say that trying an existing arrangement is a bad thing
for the DIYer, but clearly for a professional it would be stupid to
use anything other than good quality cables and antennas. For the
DIYer installing a new reception system it also makes sense to use a
good quality antenna (not a contract grade one) and good CT100 cable.
Like other things, you can either do a job properly or you can bodge
it. Typically if you bodge it, you will have to do it again.


..andy

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