And remember -- the roof of this building is 110m, so a horizontal
antenna is high enough to have pretty good low angle radiation! See
http://k9yc.com/VertOrHorizontal-Slides.pdf and double the heights for
the graphs of 80M performance. When you're thinking height, consider
the building a tower -- it's mostly the far field reflection that
determines the vertical pattern.
As to "ground" for a vertical antenna -- let's not confuse the word
"ground" with counterpoise or "radial system." An end-fed current-fed
vertical needs a counterpoise or radials, NOT a connection to earth.
I strongly concur with the advice to spend some serious time LISTENING
on that roof before doing anything else. It's pretty common for the
stuff described on that roof to be MONDO NOISY, and it's unlikely that
you can do much about most of it unless the guys who maintain it are HF
hams.
73, Jim K9YC
On Fri,8/7/2015 8:02 PM, Garry Shapiro wrote:
And Bob Brown used a monograph by J.A. Ratcliffe--"The Magneto-Ionic
Theory and its Application to the Ionosphere" which says the same
thing. It has to do with the angle between the E vector and the
Earth's Geomagnetic Field, which is horizontal at the geomagnetic
equator. Bob borrowed my copy of the book when he was writing the Big
Gun's Guide.
Garry, NI6T
On 8/7/2015 6:24 PM, Greg - ZL3IX wrote:
Careful Mike! Jakarta is close to the equator, and power coupling is
likely to be better from a horizontally polarised antenna, especially
in an E-W direction. Ref The Big Gun's Guide to Low-Band Propagation
by Bob Brown, NM7M (SK)
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