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Old November 9th 05, 06:13 AM
Owen Duffy
 
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Default ladderline to coax adapter

On Wed, 09 Nov 2005 03:25:47 GMT, 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?


I knocked up a quick graph of the attenuation from point x to the load
for this scenario. (I think / hope it is correct!)

http://www.vk1od.net/lost/W551Example.htm

Is the shape of the curve (the cyclic variation over each electrical
half wave diminishing away from the load, and the general shape of the
curve a surprise? The effects plotted here might not be explained by
the ARRL charts.

Owen
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