[TowerTalk] Where did 0.6 come from?

[Pete Smith N4ZR]

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73, Pete N4ZR
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On 2/9/2013 12:13 PM, kr2q at optimum.net wrote:
> 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
>    
>   
>
>
>
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