An interesting number of significant figures, if it's to cover both
RG-58 and RG-11 types. I'd expect the RG-11 to converge a bit better
to 72-75 ohms, actually. I have a note I made some time ago in a
reference book that says, "Neglecting dielectric loss, if Zo = Ro+jXo,
Xo is approximately -0.180*Ro*A100*VF/f" where A100 is the attenuation
in dB/100 feet and f is the frequency in MHz. There. Now, at least
for RF, people should be able to generate their own tables.

Cheers,
Tom

"Reg Edwards" wrote in message ...
For anyone who may be interested.

Typical of RG-58 and RG-11 type cables.
Zo = Ro - jXo
Xo is always negative.
Angle of Zo in degrees. Always negative.
VF = relative velocity.

Freq Ro jXo Angle VF
------ ------ ------ ------ ------
50 Hz 967 -965 -44.95 0.034
1 kHz 220 -213 -44 0.151
10 kHz 80 -58 -36 0.41
100 kHz 56 -9.3 -9.5 0.59
1 MHz 52.4 -2.4 -2.7 0.63
10 MHz 50.7 -0.76 -0.86 0.65
100 MHz 50.2 -0.23 -0.27 0.66

Smith Chart calculations begin to be inaccurate around 2 MHz and below. So
do SWR meters.