On Sat, 23 Sep 2006 04:32:51 GMT, "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

A widely accepted line loss model is that attenuation = k1 * f^0.5 +
k2 * f, your approximation makes k2=0.

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.

Not surprised at all, many of the figures in the article at
http://www.vk1od.net/G5RV/index.htm show the loss in ladder line in a
G5RV feed system. Fig 3 shows that dry ladder line loss is not
insignificant in the general sense, and Fig 8 shows the expected
degradation on "wet line" in that application using Wes'
characterisation.

Owen
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