Cecil Moore wrote:
Roy Lewallen wrote:

A transmission line can be very lossy, yet have a completely real
characteristic impedance.


That's what I thought. Is RG-174 one of those transmission lines?

No. Distortionless lines are specially made, or periodically loaded with
fixed components to achieve distortionless characteristics.

Incidentally, I recently carefully measured the Z0 of nine pieces of
RG-58 type cables at 10 MHz. R varied from 48.1 to 57.2 ohms, and X from
-0.67 to -2.32 ohms. I made one measurement at 1 MHz, on a cable whose
Z0 at 10 MHz was 49.0 - j0.69 at 10 MHz. That cable's Z0 at 1 MHz was
50.7 - j2.05 ohms. I wasn't able to make good measurements below 1 MHz
with my setup.

. . .

Roy Lewallen, W7EL