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[DPRG] Did you test real distance of RF communication (BlueTooth, Wi-Fi, ZigBee)?

Subject: [DPRG] Did you test real distance of RF communication (BlueTooth, Wi-Fi, ZigBee)?
From: Tom Brusehaver cozytom at gmail.com
Date: Mon Sep 3 16:17:03 CDT 2007

Back in a previous life, I worked on the alarming system for
an analog microwave system (10GHz). The towers were about
30 miles apart, I think we were running 10 or 20 watts. Basically
each station had two transmitters and two receovers, all directional
antennas.

One of the many alarms we had was amplitude, how many dB's
of signal we were getting, from one station to another.

Every fall, over Kansas, the amplitude was way down for about
3 weeks. It seemed to get better from the south, and work its way
north. Lots of testing and checking, some guessing, and eventually
someone figured out that the corn or wheat was have an effect on
the amplitude.

The towers were designed to be just high enough. The curvature of
the earth would determine the height. The corn would be 8 ft tall or
whatever, and would partially block the signal. Once they harvested
it, The signals would return to normal.

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