[TowerTalk] Antenna & Tower Wind Load Ratings

[Clay Autery]

Sounds like a definite improvement....  Don't forget the caveat for the
tower folks that needs to be included about feed-lines, control cables
at al.  An LMR-600 or 900, 1200, etc. feed-line is a significant
projected area...  Can't imagine the integral you'd need to use since
the effect would need to be weighted against altitude...

For now, I'll just continue to over-engineer and over-specify like I
always have.  :)

73,

______________________
Clay Autery, KY5G

On 6/15/2017 11:56 AM, JVarney wrote:
> The core problem here is the ham consumer is not being given
> compatible and concise data from which to make an informed choice.
> There's only one way for antenna ratings and tower ratings to fully
> compatible and that's through the "Aa" projected area term in
> TIA-222-G.  Antennas and towers should be rated like this:
>
> ===
>
> TRIBANDER MODEL XYZ
>
> Aa = 11.0 square feet*
>
> * TIA-222-G 100mph wind speed, height 100 ft, Exposure Cat B, Risk
> Category I, Topography Cat 1.
>
>
> CRANK-UP TOWER MODEL ABC
>
> Max capacity Aa = 16.0 square feet*
>
> * TIA-222-G 100mph wind speed, height 70 ft, 75 lbs. weight,
> antenna 3 feet above tower top, Exposure Cat B, Risk
> Category I, Topography Cat 1.
>
> ===
>
> "Aa" provides the "Apples to apples" linkage between tower
> and antenna.  Maybe that's why they chose Aa as the name of the
> term :-)
>
> I have no connection to or business with AN Tower but I commend
> them for publishing full and complete 222-G tables for their products. They
> rate their towers by Aa square footage.
>
> The industry standards are there. It's a matter of coaxing the
> manufacturers of both towers and antennas to label their products
> accordingly.
>
> 73 Jim K6OK
>
>
> ===
>
> Kurt Andress: "There are basically two types of "Antenna Area"
> values to be considered....."
>
> Jim Lux: "Tower mfrs cite a "X square feet" as opposed to
> a "X lbs load"
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