John, N9JG wrote:
You probably should read the article yourself, but Table 1 of the article
contains columns for matched line db attenuation per 100 feet for dry and
wet lines. This set of data is from measurements made at 50 MHz. Since
attenuation scales as the square root of frequency, I came up with a rough
estimate for loss at 7 MHz. The author then goes on and uses modeling to
predict some surprisingly large line losses for the G5RV antenna at 1.9 MHz.

Resistive conductor loss is proportional to the square root of
frequency, because of the relationship between skin depth and frequency.
The loss of wet ladder line is almost entirely dielectric loss, not
resistive conductor loss. In good dielectrics, loss is directly
proportional to frequency. However, water is quite different from a good
dielectric and with different loss mechanisms, so I wouldn't hazard a
guess as to how it might vary with frequency.

In an experiment I did many years ago with 300 ohm twinlead
(http://www.eznec.com/Amateur/Article...eed_Lines.pdf), I found
that the loss of wet line was significantly different just after it
rained (when the line had presumably accumulated dust) than after it
rained for some time.

Roy Lewallen, W7EL