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Posted by RMDumse on September 3, 2007, 10:48 am
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> Have you ever done tests in the fields - how long is the distance for
> BlueTooh, Wi-Fi, ZigBee, etc.?
I did rough tests on BlueTooth modules of both Class I and II. I found
the short range unit very crisply 10 meters of just less. The higher
power one seemed well over 30 meters, even through an intervening
concrete wall.
I have tested the Pro XBee's from MaxStream. They are very much as
they describe them. They say up to a mile. We ran a test putting one
unit on a car, and the other 1) at chest level, 2) at ground level. We
captured the stream from a GPS module, and retransmitted it to a
recording laptop. Then we looked at the stream of data for the
coordinates which were the farthest away, but with the transmission
still in tact. Then we used google earth to plot and thus measure the
distance. In the first case, we got a maximum distance of 1.2 miles.
MaxStream claims up to 1 mile. In the second case we got .49 miles.
You might want to look at the MaxStream web site. They explain "the
fresnel effect" about clearance of antenna from surrounding objects.
At 2.4GHz (frequency domain of all the items you listed) you need
about 3.5+ meters clearance (at both ends) from anything around the
antenna for maximum range. Probably the shorter range results you
experienced were due to this antenna placement.
--
Randy M. Dumse
www.newmicros.com
Caution: Objects in mirror are more confused than they appear.
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> BlueTooh, Wi-Fi, ZigBee, etc.?