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[TowerTalk] Verticals and Metal Roofs

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Subject: [TowerTalk] Verticals and Metal Roofs
From: n4zr@contesting.com (Pete Smith)
Date: Fri Jul 18 07:04:59 2003
At 09:16 PM 7/17/03 -0800, Paul Carr wrote:
>I want to install a vertical antenna on a structure with a metal roof 
>using a tripod. What are the issues with mounting a vertical in this fashion?
>
>Does the antenna need to be mounted a certain height above the metal 
>roof?  Should the base of the antenna be grounded to the roof or should I 
>strive for isolation?  Can anyone describe actual installations?
I assume that "insulated" radials will be required.


I have an HF-9V vertical mounted above a galvanized roof.  I used two 
8-foot 1X6s, crossed, with a pipe flange and about 2 feet of pipe - the 
antenna's base section simply drops into the pipe.  The resulting base is 
quite stable with this 26-foot-tall antenna.

Although I was told that I should use resonant radials, what I did instead 
(the roof is about 30 x 16 feet, 10-12 feet above ground) was to use two 
125-foot wires attached to the ground side of the antenna, laid on the roof 
so as to couple to each section of roofing material.  I also connected the 
ground side directly to the roof.  I don't doubt that a couple of resonant 
radials would probably make a better counterpoise for 80 meters, but I 
didn't do that.

The antenna is used chiefly as a second radio antenna for contesting.  It's 
no great shakes compared to my primary antennas, but in a couple of 
contests last fall (CQWW and SS, both CW) I think I worked everything I 
called with it (and 100 watts), including a number of Europeans.  I was 
pleasantly surprised.

73, Pete N4ZR
The World HF Contest Station Database was updated 17 June 03.
Are you current? www.pvrc.org/wcsd/wcsdsearch.htm



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