Alan Melia said

Hi Peter, the immediate thought is DSL ( or ADSL) or even ISDN lines. I
would not lay too much store by BT "engineers" not being able to find it.
These guys have little or no RF experience in general. Because it is so
wirespread, I would suggest it is a system effect rather than a fault
somewhere, and it would seem to correlate with the increased penetration

of

"broadband". This could explain why some "diss poles" are not as noisy as
others.

Many thanks to Alan and the rest of you who responded regarding my QRM
problem.

I don't think that the noise is generated by BT even though it is being
radiated by some of their distribution systems.
Last week we had a power cut that affected an area of around one or more km
radius and the noise (almost) disappeared. I think most ISDN etc is powered
from the exchange.
All the interference comes down the antenna. I can reduce it considerably by
parking my beam so that the deepest null is on the source of the noise. The
noise is very broadband (I can hear traces of it on the 10 and 18MHz band)
and is average S7 throughout the 14MHz so not an apparent harmonic.

Peter, G3LDO