Topband: Tower Question

w0ah at w0ah at
Tue Oct 21 10:49:32 EDT 2003

A friend of mine, near Denver, had a profession installation of a 50'
Rohn 25 tower with insulators on the 3 legs at the 10' level and
phillystrand guys.  He has a mast extending 15'above the top of the tower
with a 28' boom 7el M2 6M beam at the 62' level and a CC A-3 just above
the top of the tower at the 51' level.  Of course,he has two runs of coax
and one rotar cable going up the inside of the cable.  The professional
tower installer, a ham, told him that the tower could be used on 80M, but
with the coax and rotar cable, he can not resonate it.  Is there an easy
way to isolate the cables going up the inside of the tower OR would it be
easier to bypass the insulators so that the tower is grounded- and then
shunt feed it.  If shunt feeding is the way to go, can someone please
model the gamma-wire tap height for 80M and the gamma or omega matching
capacities.  I promised to help get him on 80M (and 160M, but that's
another story) before the snow flies.
Doug W0AH

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