In article ,
Jeff Liebermann wrote:

On Thu, 19 Jul 2012 06:56:18 -0700 (PDT), klem kedidelhopper
wrote:

Never thought of using Romex for RF. It would indeed be interesting to
see what it's characteristic impedance would be at different
frequencies though.

Nope. It's quite constant. As I vaguely recall (and can't find my
notes), it's about 110 ohms between outside conductors for 14-2 NM-B.
There's nothing in the dielectric and insulation to absorb power, so
the impedance is going to be constant up through UHF frequencies.

The impedance may not change, but I'm pretty sure the insulation in
Romex is vinyl, and I'm pretty sure it has a serious loss factor above
HF. There's a good reason you see polystyrene, mylar, mica, glass, and
teflon capacitors, but not vinyl capacitors.

Isaac