Owen Duffy wrote:
We were discussing an example based on Wireman 551 ladder-line. The
dominant factor affecting loss at 30MHz is the series resistance
element. Does it make sense that since in that example, the magnitude
of the current varies by nearly 25:1 along the line, that the I**2*R
loss per unit length along the line is not constant, and will vary by
a factor approaching 625:1?

25% of the power is delivered to the load. There are eleven current
maximum points in 100m on 10m. Does that 11% of the feedline really
contribute 59% of the losses? Does the remaining 89% of the feedline
really only contribute 41% of the losses?
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73, Cecil http://www.qsl.net/w5dxp

On Wed, 09 Nov 2005 05:46:00 GMT, Cecil Moore wrote:

Owen Duffy wrote:
We were discussing an example based on Wireman 551 ladder-line. The
dominant factor affecting loss at 30MHz is the series resistance
element. Does it make sense that since in that example, the magnitude
of the current varies by nearly 25:1 along the line, that the I**2*R
loss per unit length along the line is not constant, and will vary by
a factor approaching 625:1?

25% of the power is delivered to the load. There are eleven current
maximum points in 100m on 10m. Does that 11% of the feedline really
contribute 59% of the losses? Does the remaining 89% of the feedline
really only contribute 41% of the losses?

When I have written about loss per unit length, I have implied "loss
at the rate of y per unit length". If you have tried to apply the 4+%
figure to one meter at each maximum, then you are unlikely to get any
meaningful results for a number of reasons. See the graph I just
posted (our posts crossed in the mail so to speak).

I haven't stated it it the post, but it should be obvious that the
rate of attenuation is the slope of the line in the plot referenced in
the post.

Owen
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