I just put a 2-element 40-meter vertical array in service using the
Christman feed, cut for 7060kHz. I used my VA-1 to cut the 4 lines to
1/4-wave, measured the lines, calculated the length necessary to get 71 and
84 degrees and trimmed accordingly. There is a little waste but it was worth
it for the sake of simplicity.
I have had the antennas in service for a couple of weeks and find about 20db
of f/b ratio, which is in accordance with the EZNEC calculations I did
before proceeding. My "common point" complex impedance is close to the
predicted value but I have not yet built a matching network to bring it to
near 50 j0. The tuner in my IC-746 handles the present impedance well.
The antennas are on a 75/255 azimuth, primarily to reduce signals from the
US midwest and east coast when working the Pacific/VK/ZL. It seems to work
pretty well in spite of the drawbacks I've heard about this feed system.
On Sun, Apr 11, 2010 at 3:18 PM, <vk3pa@vk3pa.com> wrote:
> Gdy all, my Q is I need to cut phasing lines for 7.050 Mhz of 84
> degrees es 71 degrees! ok So far, now 360 degrees = 1 wave length, so
> 0.5 wavelrngth (=180 degrees) would be 468/freq /vf es / by 180 would
> be 1 degree so x by required degrees eg 84 es 71 ok ! so now how do
> I convert 84 es 71 degrees to a frequency so I can cut the lines WITH
> my antenna bridge rx vector analyst autek VA1?? OR AM i WAY OFF IN MY
> THINKING!! 73 es tnx Al vk3pa
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--
Jack, W6NF
Silver Springs, NV
DM09ji
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