Contrary to what people might believe there isn't a
clean transition between perfectly OK to not OK at all.

There is with the ALL OF THE COUNTRY which was clearly what
was being discussed in the original comment still right at the top.

I don't know if you've experienced it but on a Broadcast DAB
system a phenomena known as "bubbling mud" happens when
reception is in this transition phase.

The GSM digital cliff is something else entirely.

The digital "cliff" isn't that well defined. Some think its the point
where bit errors start to occur, some think its when all the bits fail.

In any digital communications system thats anywhere near practical there
will be a system for error correction. Especially using such a variable
as radio. This can result in what's described as pixelation on a TV
system or a garbled sound on a radio or voice band channel.

If the errors get too great then the radio or TV can do a full mute if
its designed to do so.

I'm sure there are a lot on here who have this experience with digital
TV reception of pix freezes and pixelation which is distracting, but it
doesn't usually case a complete pix mute. If it did for a lot of people
digital TV reception and radio for that matter would be neigh on
impossible..

And for that matter mobile comms too..



Mobile phones have been doing just that
since the GSM system was implemented...

Separate issue entirely to the digital cliff being discussed.

there are areas within the otherwise usable service area
of a base station that are difficult owing to topography..

Thats a different matter entirely.

Do you have any hilly areas like say the Welsh valley's?..

Corse we do.

It's course BTW...

Nope.

Well up here it is...


Then you'll have pockets of poor reception or rather communication..

Nothing to do with what you originally were talking about.

Not what you understand..
--
Tony Sayer