Paul,
The metal roof edging is not a continuous single piece but crimped and
painted such that we did not feel it a reliable RF conductor. It was
galavanized steel and attached to wooden boards that stay damp when there
has been a rain. The flat roof is gravel over tar, a common commercial roof
here, and tends to pool water after heavy rain. Not a good RF environment.
We plan to shorten the loop to a Delta with one corner on our beam tower at
the edge of the roof. Other corners will be tied to sloping non conductive
guys to screw anchors at far edges of roof. Hopefully raising the loop
about 3 feet at lowest point above the edging will give us a tilted but
useable NVIS antenna which is what we need for statewide work for the Red
Cross where the station is located. Probably will feed at the highest point
by the tower; but could play with that depending on results. The tower is
convenient to our roof jack where all the feedlines enter the shack, and
thus would minimize feeder if used as the feed corner. We have to hang the
loop corner there at least 7 feet above the roof edge, so that our tower
climbers can step off the tower to the roof top to do feedline maintenance.
We also have other antenna masts and a surveyed GPS pedestal on the roof,
which have feeders to maintain.
-Stuart K5KVH
73,
Stuart
K5KVH
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