On Nov 1, 1:17*pm, Jeff Liebermann <je...@cruzio.com> wrote:
> On Fri, 31 Oct 2008 19:50:33 -0700 (PDT), jimmi...@gmail.com wrote:
> >While working on an airport S band radar I taped my WiFi detector to
> >the feedhorn and rotated the antenna. I was picking up signals from
> >all over the place, at least 100 different ones probably more that I
> >could not discern from the others. With the detector removed from the
> >feedhorn I could only get 4, I think they are all the WiFI for the
> >airport.Gain of the antenna is 31db with a cosecant squared vertical
> >radiation pattern. Its amazing what a really good antenna will do.
>
> >Jimmie
>
> Doing the math.... well maybe not... my calculator battery just died.
> Ok, the hard way... range doubles with every 6dB of gain.
> *gain = range increase over 0dBi gain
> * 6dB = *2x
> *12dB = *4x
> *18dB = *8x
> *24dB = 16x
> *30dB = 32x
> So, you've picked up perhaps 32 times the range or 32^2 = 1024 times
> the coverage area with the rotating antenna. *If you assume a uniform
> density of access points, you should hear 1024 times as many. *Nice.
>
> The local airport (WVI/KWVI) has about 100 access point scattered
> around the hangars, neighboring businesses, flight skools, and airport
> offices. *My guess is about 25% are wide open and set to the default
> settings (SSID=linksys).
>
> Um.... *How did you read the wi-fi detector while the antenna was
> rotating? *It must have been quite a ride.
>
> --
> Jeff Liebermann * * je...@cruzio.com
> 150 Felker St #D * *http://www.LearnByDestroying.com
> Santa Cruz CA 95060http://802.11junk.com
> Skype: JeffLiebermann * * AE6KS * *831-336-2558
We were doing maint on the antenna. It was shut down at the time.
Jimmie
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