On Tue,11/25/2014 12:18 PM, Doug Turnbull wrote:
Surely a dipole or Yagi has a certain maximum
height beyond which not much is to be gained by going higher even for DX -
QST did a study of the optimum height for a Yagi a number of years back.
A wavelength above ground was generally best though of course by going
higher lower angles were favoured and thus perhaps at times more distant DX.
Beyond a certain height though I doubt there is that much gained unless one
switches between antennas or stacks and this is well beyond the nature of
the original question.
Earlier in this thread, I posted a link to a presentation at the
Pacificon Antenna Forum about a study I did on exactly this topic, and a
few others.
http://k9yc.com/VertOrHorizontal-Slides.pdf
I know boom length is important but are you saying that given a long
enough boom that a three element mono-band Yagi would outperform a six
element Monobander on a fifty foot boom. The additional elements surely
do add some forward gain - some.
The well known principle is that the gain of a Yagi is dependent both on
boom length AND optimization of the design. A three element 20M Yagi on
a 50 ft boom would NOT be an optimized design. :)
I know it may only be one to three dB and hard to recognize in the QSB.
One or two dB can be a lot if it gets you above the noise. I've worked a
lot of DX by adding a couple of dB to my signal by carefully tuning the
amp after a QSY.
73, Jim K9YC
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