[TowerTalk] trees and verticals

[john at kk9a.com]

A vertical is not a great antenna on 40m, unless of course you have the base 
in salt water.   I just did a quick model of my lower shortened 2el 40m beam 
which is at 75 feet and a vertical that I had already had a model of (which 
was not elevated).  The low yagi is 11dB stronger in the direction that it 
is pointed at most useful lower radiation angles.  The yagi is even 4 dB 
stronger off the back.  I did not compare the side lobes, but a 2 el beam is 
not that directive so I doubt that the single vertical would ever be better 
except for very high angle radiation which I have never seen on 40m.  I do 
not think that  you can contribute your poor vertical performance to tree 
absorption.

73,
John KK9A



To: towertalk at contesting.com
Subject: [TowerTalk] trees and verticals
From: kr2q at optimum.net
Date: Tue, 27 Dec 2011 15:53:20 +0000 (GMT)

My FYI tale of vertically polarized antennas and trees.

I have always lived in very heavily wooded areas and have always used
horizontally
polarized antennas on the top of crankup towers.  They clear the tops of 
"most"
of
the trees, but not all.  They work REALLY WELL (I have an outstanding QTH) 
for
DXing.

Wanting to "save rotor time," while contesting (with my 402CD), I put up a 
GP
(elevated
vertical).  It hangs from a tree.  It is "full size" and has full sized
elevated radials.  My hope
was that it would be louder than my 2L 40 when the 40 was pointed at EU (50
degrees
from NNJ) when I heard a new mult from the south (zone 8, 9, etc).  The 
"base"
of the GP
is about 20 feet above ground (and so are the radials, but they slope down
somewhat).  It
was to be my "multiplier" antenna.

That was not the case.  The elevated vertical (GP) is always "weak" compared 
to
the 2L
40, even when the yagi is pointed at EUR and I'm comparing to the South.
The 40m yagi is at about 80 feet.

Now, I would expect the yagi to be louder to EUR as compared to the GP, but 
not
so
to CA/SA, which, at best, is off the back corner of the beam when beaming 
EUR.

The GP vertical element is supported by the trunk of the tree, so it is 
"right
next to" the
tree trunk.

<snip>
de Doug KR2Q