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Re: S-Band Antenna Comparisons, etc.



on 1/8/01 3:34 PM, NS1Z at ns1z@arrl.net wrote:

> I'm having difficulty picturing how a ribbed design can have more wind
> resistance than a solid sheet. Maybe the PCS guy really meant total weight,
> as I can see ice forming between ribs adding weight and wind resistance.
> This assumes that both antennas are made of thin aluminum sheet. Most dishes
> are not, leaning more to heavier/thicker aluminum to maintain the shape.
> However, once the surface is solid, how can it produce more wind resistance
> than another solid form of the same size........

Easy.  You have much more surface area for the ice to form on in a ribbed
configuration.  Look at how much ice can form on a yagi during an ice storm.
In the mesh antenna configuration, ice can form around every single element.
Now your windloading increases due to the surface area of the ice.  You
don't really get that much ice forming around the center of a solid dish.

Hey, it surprised the heck out of me too, but this was from the chief system
engineer of a major carrier in the Chicago and Milwaukee area.

73,

Jon
NA9D

-------------------------------------
Jon Ogden
NA9D (ex: KE9NA)

Member:  ARRL, AMSAT, DXCC, NRA

http://www.qsl.net/ke9na

"A life lived in fear is a life half lived."

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