Hello Topbanders,
This Summer with the urging of Jeff K1ZM, I finally got around to replacing
my aging 21 year old tower and most of the antennas. So now comes the task
of shunt feeding a new tower. As it is in the 90s here and since I really
do not relish the thought of having to climb the tower more than I have to,
I thought I would come to this esteemed group for your collective wisdom on
the task at hand.
The tower is 85 feet of 25G and 12 feet of mast with three sets of 3/16 EHS
guys broken up by insolators. At the top is a 40 rotary dipole, below that
is a five el six meter yagi, below that is an A3WS with 30 meter add on kit
and at the bottom of the stack right above the thrust barring is the new
Cushcraft X7. The elements on the X7 are insolated from ground and the boom
is 18 feet long. BTW, the boom on the A3WS is I believe 12 feet and two of
the elements are grounded. Boom on the six meter yagi is also 12 feet and
all elements are grounded.
So, the question is where is the most likely spot on the tower to attach the
shunt feed? On my 65 foot tower with a 204BA a 10/15 three element yagi and
the six meter yagi, I attached the shunt at aprox. 56 feet with good
results. Of course, this tower is significantly taller with a fair amount
of toploading so I am really not sure where to start.
Thanks in advance for your suggestions and your assistance.
73, Bob K3UL
--
FAQ on WWW: http://www.contesting.com/topband.html
Submissions: topband@contesting.com
Administrative requests: topband-REQUEST@contesting.com
Problems: owner-topband@contesting.com
|