On Sun, 19 Aug 2007 14:49:31 -0400, James M. Daly wrote:
>And on a side note; is there any significant advantage to using 9913 coax
>over RG-213 at these lengths when operating at 10-20m frequencies?
The best answer to that is to plug some feedpoint impedances (or SWR) values
across the bands into the TLW software that comes with the antenna book and
let it crunch the numbers. I just did that for the 150 ft long feed to an
80/40 dipole and plugged the result into a spreadsheet to study it. The math
told me that the difference between Belden RG6 with a steel center and 8213
(RG11 all copper) was about 0.6 dB averaged over 80 and 40, taking SWR into
account). LMR400 might have given me another tenth dB or so. The decision was
made easy for me when I found a surplus spool of 8213 for about $.30/ft. :)
One of my neighbors, K6XX, has a significantly longer run than that to some of
his towers. He uses parallel hardlines, which he then combines to a single run
that goes up the tower. There are lots of ways to skin that cat. Ya pays yer
money and ya takes yer choice. :)
73,
Jim K9YC
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