[Chris Siz]

On Sat 03 May 2008 19:05:41, Kevin McMurtrie wrote:

In article ,
Chris Siz wrote:

I am in the UK and have a 10m length of some cheap TV aerial
coax. It came from a discount store as a TV coax extension
cable. I measure the cable diameter as 4.8mm.

(1) Is it ok to use this sort of coax for a microphone? I don't
want an impaired audio signal. The length I need to use is 3 to
4 metres.

(2) Is it ok for UHF TV or is it actually quite low grade coax
and prone to interference or mess up the aerial signal?

There are a few differences. TV coax will work in some conditions
but not generally.

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.

TV coax may not pass small audio signals well because of its
aluminum shield. Aluminum is extremely reactive so it is always
coated with a thin oxide layer. Higher voltages can spark through
it and TV RF can capacitively couple through it. Microphone
signals might become distorted. Cable for lower frequencies uses
copper shielding.

Good microphone and instrument cable has an insulation that drains
away static electrical charges. RF coax can contain electrical
charges in the insulation that causes it to act like condenser
microphone.


I am the OP and as you can probably tell I am no electronics or
radio expert. However even my limited knowledge struggles to
believe some of the points you have made.

Forgive me if it's more obvious to others but your's is not some
sort of funny posting is it?