allan1 dejazzd.com wrote:
>I am looking to put up 2 EWE antennas so as to be bi-<BR>>
>directional.
>
Sorry I couldn't decript "bi-<BR>>", but I will take a stab at
an answer anyway.
There are several ways to feed two EWEs, phased broadside (side by side
end fire cells in phase), phased endfire, or independently. Phased
endfire will provide the narrowest lobe and the best signal to noise
ratio, but with only two you will be limited to two directions (provided
you add the hardware to reverse directions). Phased broadside will
also limit you to two directions and have less performance than the end
fire version. With two independent EWEs placed at right angles to each
other and hardware to reverse directions you can cover 4 directions but
with much wider lobes and poorer signal to noise ratio.
You could feed an EWE at the top but it will be more difficult to keep
the common mode currents and signals on the outside of the feedline from
getting into the antenna. It will also make the directional switching
much more difficult. I can't see any reason for doing this.
An EWE for 160 can be made a little larger than the recommended size for
160/80/40 (10 x 15 ft). That will give a little more gain but the 160
pattern won't improve and you will lose performance on the higher
bands. EWEs in end fire can be separated from each other or placed very
close together. Separating them will give more gain and a very small
improvement in pattern at the cost of requiring more hardware. More
gain will reduce the problem with common mode currents and intermod.
If I could figure out exactly what you asked, maybe the answer could be
more specific.
Jerry, K4SAV
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