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Reply To: | Mike Duke, K5XU |
Date: | Tue, 5 Oct 2010 17:57:15 -0500 |
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Yes, they will work very well.
As Butch said, however, the manufacturer's tuning chart is pretty
worthless for such an installation. That's because the chart is
usually for a ground mounted installation, or a roof top with only 4
or 8 radials.
Two experiences with metal roof top verticals come to mind.
Shortly after my brother and I got into CB radio, I went to spend the
week with my grandmother in Alabama. Her house had a tin roof, so my
dad rigged a clamp to fasten the mobile antenna near the edge. We were
all blown away by how well that temporary setup worked. I could hear
as well as the guys around me who were running ground plane type
antennas, and managed a respectable transmit signal too.
When the higher hf bands were beginning to wake up in 1977, a friend
who ran a furniture and appliance store decided to put a 15 meter
vertical on the roof of his 4,000 sqft steel building. His vertical
was made from 2 pieces of tubing which his store was selling as
"closeline poles." He fastened them together, and installed it on a
television antenna tripod, using a glass catchup bottle as the base
insulator between the bottom of the antenna and the roof.
At the time, I was running a Swan 500CX with a 2 element Hi-gain quad
at 60 feet. My friend was a mile away, running that vertical with a
Viking Ranger that belonged to his uncle.
He could work anything he could hear with that rig on AM, and he would
beat me in the pileups 99% of the time with his 75 watts on cw vs my
300.
Mike Duke, K5XU
American Council of Blind Radio Amateurs
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