Re: OK to use TV coax for microphone?

On Sun, 04 May 2008 08:32:49 -0700, Richard Crowley wrote:

> "Don Pearce"  wrote...
>> As I said in my first reply, if I was forced to use coax for a
>> microphone, domestic TV grade would be a very poor choice because in
>> general it has perhaps no more than 10% screening (just enough in fact
>> to give the cable a stable characteristic impedance, but no more).
> 
> That may be the case over there

Over there? Over here we find lots of 72 ohm tv coax on sale in the diy
stores which has very poor screening. In fact I'd say the majority of
terrestrial tv antennas in the Uk are wired with it.

> (although I doubt it). Over on our side of
> the earth, RF cables, and especially those intended for television use
are
> 100% ****elded. Because if they are not, it starts causing problems.
> Problems for the cable operators

Well yes, cable tv operators even over here use much higher quality coax.

<snip>

> Don't mistake the wire braid (which may, indeed be only 10% coverage)
for
> the actual outer ****eld of the coax which is the active ****tion.

I don't think any regular in this ng is going to make a mistake like that.
 
>> Microphone signals are too small to mess around this way. Decent audio
>> grade cable has screening approaching 100%.
> 
> And out in remote rural areas, RF signals are of the same order.

Most areas here (UK) have excellent analogue signal strength.

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