jerry wrote:
> kurt
> are you saying that the antenna manufactors use a figure like .67 so
> allow for the round shape of the antenna tubing and the impossibility of
> having all the antenna flat to the wind at one time because the boom and
> elements are at right angles to each other and the tower makers use the
> flat figure to max. the wind load to sell the towers . jerry n6ifw
Hi Jerry,
Nope, that's not what was meant.
Most towers are designed in accordance with published specifications.
Amateur antennas are not.
The tower guys are using projected areas because that's the way the
spec's work. Allowances for the shape of the antenna members is treated
inside the tower design spec. We need to feed the tower design a
projected area and let it take care of the rest.
The antenna guys have been using the 2/3 drag coefficient, which came
from the EIA-222-C tower spec (pre 1987), to show us the effective
areas.
That would be ok for comparing antennas, if everyone was doing the same
thing.
We need to find out how the antenna areas were derived so we can be sure
we are properly loading the towers.
--
73, Kurt, K7NV
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