[TowerTalk] Building Top Vertical

John E. Cleeve g3jvc at jcleeve.idps.co.uk
Thu Jul 30 10:20:14 PDT 2009

	I had this problem when working as SM0/G3JVC in Stockholm back in
the mid 80s. There I had a top floor apartment at 16 floors up, and with a
private mini roof garden, you could then just stepped over the small wall
onto the copper sheet covering of the main roof and could walk to the edge
of the building. The winds and ice loading during the winter were very
difficult to deal with, however I chose to use the sailing yacht solution
for stabilising the mast.

	I treated my multiband vertical antenna as though it were an upside
down yacht mast, in that I had the rigging spreaders in the form of a cross
set at right angles to and at the base of the antenna. The vertical was then
guyed at the top and about half way down, with the guys terminating at the
tips of the spreaders. The stress at the tips of the spreaders was taken by
additional separate guys back to the base of the support pole, which was
clamped to the building (lift motor room). I found all the fittings and guy
rope I needed by "trawling" the local yacht chandlery.

	This system was transferred back to my UK address in time for the
October 87 hurricane, with winds in Surrey gusting at 110mph, the chimney
stack on which the support pole was clamped, went over, at the damp course,
due to wind pressure, but the guyed vertical assembly remained stable and
intact and the vertical antenna was undamaged.

	I would suggest that this solution may provide some food for
thought, I hope so. 73, sincerely, John G3JVC. 

-----Original Message-----
From: towertalk-bounces at contesting.com
[mailto:towertalk-bounces at contesting.com] On Behalf Of Doug Rehman
Sent: 30 July 2009 16:29
To: towertalk at contesting.com
Subject: [TowerTalk] Building Top Vertical

We need to replace the Hamstick dipole on top of our EOC with something that
will offer reasonable performance on 75/60/40. The EOC is in a five story

Here are the limitations:

1) It's for an EOC, so the survivability needs to be in the neighborhood of
100 MPH

2) It must be a vertical- no wire antennas allowed

3) No radials on the vertical (unless they're only about 18")

4) It will be mounted to the wall of the elevator penthouse

5) It can be tied into the perimeter lightning ground

6) No guy wires

7) The simpler the better

I'm leaning towards something like a marine HF antenna with an auto tuner at
the base (I know the auto tuner violates the simple part, but it needs to be
usable by persons with limited knowledge- a manual tuner is out of the




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