At 10:33 PM 7/18/2005, Richard (Rick) Karlquist (N6RK) wrote:
>The 104 ft boom seems rather short for 4 elements. This
>would be like 26 ft on 20 meters. I have heard of 3 element
>20 meter beams on 26 ft booms.
>
>Also, if you were going to insist on 4 physical elements,
>why not drive the inner two as a log cell and get more
>bandwidth? (Like the 4 element KLM 40 meter Yagi).
>
>Rick N6RK
Actually the venerable 204BA was on a 26 ft boom. Not the
best in times of computer optimization but still a pretty good
antenna.
You don't need to drive two elements to get better bandwidth--
check out the OWA antennas made popular by K3LR.
In some ways you can think of a Yagi as a bandpass filter
and with four "knobs" (elements) to diddle you can better
optimize the F/B, gain, and SWR bandwidth over a 3 element
array on the same boom length.
--John W0UN
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