[Date Prev][Date Next][Thread Prev][Thread Next] - [Date Index][Thread Index][Author Index]

Re: S-Band Antenna Comparisons, etc.

on 1/7/01 4:08 PM, NS1Z at ns1z@arrl.net wrote:

> Hmmmm?? Is the spacing of the framework that bad? Usually the design is such
> that it approximates a full metal back but is ribbed to lighten it and
> reduce (!) wind resistance.... Something about waveguide beyond cutoff?????

The reflector is just that -> it reflects RF power to the feed.  So it
matters not which way the reflector grill runs.  As Dave Tipton pointed out,
what matters is the feed.

Your comment about reducing wind resistance or wind loading is interesting.
This is the conventional wisdom behind these.  However, I've talked to at
least one cellular/PCS operator up in my area about these.  He hates them
and uses solid dishes.  He said solid dishes have LESS windloading in
conditions of heavy ice and snow.  He said ice build up on the BBQ antennas
creates a tremendous load on it.  So he didn't use them.  Good point.  I
suppose that those of you down south who don't have regular ice or snow
build up wouldn't find that a problem.  But to anyone who has a regular
winter like we are having in Chicago, think twice about getting a BBQ dish.
In fact, its even worse for folks in say, St. Louis where you get more ice
storms than we do.  You get ice built up on that sucker and it will get
HEAVY and you gain in windloading surface area as well.



Jon Ogden
NA9D (ex: KE9NA)



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

Via the amsat-bb mailing list at AMSAT.ORG courtesy of AMSAT-NA.
To unsubscribe, send "unsubscribe amsat-bb" to Majordomo@amsat.org