TV coax is very brittle. The inner wire is copper-plated steel and the
outer shield is aluminum wire and aluminum foil. It will quickly crack
where it meets the connectors.
What planet do you live on? I have never seen TV coax as you
describe. Coax with copper-plated steel inner conductor is mostly
used as data cable (ethernet).
75-ohm with copper-coated steel center conductor is often used for
outdoor cable-company coax runs. The steel core gives it enough
tensile strength to allow long runs to hang between poles (and between
pole and house) without stretching. This stuff is often a "hardline"
coax, with an aluminum outer shield... very low RF leakage, which is
an important issue for cable companies.
Indoor TV coax is sometimes RG-59, sometimes RG-6. It usually seems
to have a solid-copper center conductor (to allow for termination via
a crimp-on F connector). The shield may be anything from one layer of
braid with poor coverage, up to a quad shield (two layers of braid,
two layers of foil). It may be fairly stiff.
Coax which is optimized for microphone usage tends to be relatively
flexible (stranded center conductor, compliant jacket), and I
understand that the better varieties are designed to minimize the
generation of triboelectric noise (which occurs when the cable is
moved, as a result of static or piezoelectric effects).
Using TV coax for a microphone ought not to be harmful, but it's
probably not the best choice, and I'd do it only if a limited budget
made it impossible to get something better suited to the purpose.
Useful reference:
http://www.belden.com/pdfs/Techpprs/tpbroad.htm
--
Dave Platt AE6EO
Friends of Jade Warrior home page:
http://www.radagast.org/jade-warrior
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