Richard Clark wrote in
:

That article does seem to have a few vague contradictions,
but I think the point about a thin foil that is adequate for UHF screening
being inadequate for HF is interesting, and I've seen that point claimed
before.

In coaxial application, the performance of the foil is limited to its
thickness, which in turn can be penetrated by low frequencies. We
know this as an example of penetration depth. The surrounding wire is
probably 10 to 100 to 1000 times thicker in that regard. The wire
will always satisfy most typical applications (VLF and up) and where
it would not is found in "coverage." Such issues are very rare and
are not elevated to important simply because you are straining to
catch a weak signal.


Ok, if I take that with the point about lower HF loss in RG6, it seems that
my easiest option of a copper-braid RG6 will be good, but this still begs one
question: If BT are using BT2002 double-braided copper and no foil, at
greater cost, what does it do for them that RG6 will not do? Would it be a
matter of transmission power, or something else?