1. I am not an engineer2. Here is where I thought "0.6" came fromBack in the
late 60's, when I was still in HS, the "square footage" of antennas was a hot
topic.There were long discussions (in person) about "how did they get that."A
common practice among my peers at that time was to "do the math" to extent we
could.Calculating surface area was easy enough, but on a round surface, there
is only one point(at 90 degrees) that "sees" the full impact of the wind. As
one approaches the 0 and 180 points, well, that "point" is barely visible to
the wind.Somewhere (I can't recall from where now), a simple approach was to
use the projection of around surface (cylinder). If you do the math, it comes
out to somewhere between .6 and .66of the surface area (using round numbers).
I always used 2/3.I hope the table below comes out OK.But either way, if you
round off to the nearest whole number, both work the same.And THAT is what I
did, way back when. Maybe completely unfounded. LOLNow, I just go by the
manufacturer specs. Probably worth checking.de Doug KR2Q
diameter
1/2 surface
use 0.6
use 0.66
1
1.571
0.9
1.0
2
3.142
1.9
2.1
3
4.712
2.8
3.1
4
6.283
3.8
4.1
5
7.854
4.7
5.2
_______________________________________________
_______________________________________________
TowerTalk mailing list
TowerTalk@contesting.com
http://lists.contesting.com/mailman/listinfo/towertalk
|