In message , Antonio
Vernucci writes
Still, nicely done. Thanks for your efforts and explanations.

tom
K0TAR

Figure 22 of http://www.qsl.net/i0jx/ros.html separately shows loss
caused by copper (in red) and loss caused by dielectric (in blue) for a
100-meter run (about 330 feet) of LMR-400 coax (similar to RG-213 with
foam dielectric) versus frequency.

The formulas used for the plot are shown just above it.

Though it is in italian, it should be easily understandable.

For the 'linguistically challenged', with Internet Explorer 8, there is
usually right-click, select "Translate with Live Search". It works very
well!
--
Ian