In message , Antonio
Vernucci writes
since most of the loss in practical coax cables is due to I^2R loss
(compared to V^2G)

A quick question. If most of the the cable loss is due to I^2R, how can
one explain that the foam versions of common coaxial cables show a much
lower loss than versions having solid PE insulation?

For instance RG-213 is rated at 8.5dB loss for 100 meters at 144 MHz,
while RG-213 foam at only 4.5 dB. If G is relatively unimportant with
regard to loss, how can one explain that a change of insulation
material yields such a tremendous change in loss?

Thanks and 73

Tiony I0JX

Lower k dielectric larger diameter inner conductor lower resistance
lower loss.
--
Ian