[TowerTalk] 40m solutions

Jim Brown jim at audiosystemsgroup.com
Mon Sep 11 16:11:49 EDT 2006


On Mon, 11 Sep 2006 15:27:58 -0400, KC1DI quoted the entire bloody message 
to add two paragraphs. Bummer. But he made some excellent suggestions. 

I have several comments. 

First, I shouldn't even tell you anything good -- being on the east coast, 
you've got at least 10 dB on us over here on the left coast going into EU!

But seriously, the first thing I would try is a half-wave (or even a 
loaded half wave if you don't have enough height in the desired direction) 
dipole sloping off the tower. Expect to see a few dB of gain over a dipole 
in the direction that it slopes. A ham in PA sells very nice loading coils 
that will shorten a dipole quite nicely under the name of Hypower Antenna 
Co. Google or look in QST to find him. They handle my Ten Tec Titan just 
fine.

The vertical angle patterns of a sloping dipole are discussed in ON4UN's 
book. At W6BX, where we have a 150 ft tower and ground sloping down away 
from the tower, I have a two-wire sloping dipole cut full size for 80 and 
40, with HyPower loading coils to make it resonate on 160. It plays VERY 
well on all bands. 

Second, the antenna system that KC1DI is talking about is thoroughly 
described in either the ARRL Antenna Book or the ON4UN book (or maybe 
both). It's basically four half slopers coming off the side of the tower, 
with some switching to change directions as needed. 

I think that both of these antennas, as well as the single half sloper, 
have fairly good low vertical patterns. 

The sloping dipole does NOT need a ground plane, and it is completely 
insulated from the tower, but the tower operates a bit as a reflector for 
it. ON4UN's book says that you can vary the angle of the antenna to vary 
the vertical pattern. 

73,

Jim Brown K9YC






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