third rural range test, ad-hoc mode

James Cameron quozl at us.netrek.org
Fri Jan 12 03:17:31 EST 2007


G'day,

I've just completed a rural range test in ad-hoc mode, using two
laptops, at a height above ground of 1.5 metres, over 1.26 kilometers
line of sight.

These results are much better than the previous managed mode results,
against my test access point.  I suspect my access point lowered the
previous results.

Both BTest-1 units were running OS build 225 with Q2B16 and Q2B19
firmware.

One unit was placed at one end of a straight dirt road, 1.5m above
ground, in open position with ears up.  The second unit was walked down
the test range.  At distance intervals, performance was analysed using
iwconfig, ping -i 0.1, and arecord piped to aplay over ssh to listen to
the wind on the microphone of the base unit at 8000 Hz.

The results from on the second unit are:

200m, signal -72 dBm, noise -85 dBm, rate 11 Mb/s, all okay,
400m, signal -77 dBm, noise -89 dBm, rate 5.5 Mb/s, all okay,
600m, signal -84 dBm, noise -89 dBm, rate 1 Mb/s, all okay,
950m, signal -84 dBm, noise -85 dBm, rate 1 Mb/s, some ping loss,
1260m, signal -87 dBm, noise -89 dBm, rate 1 Mb/s, more ping loss.

(the rate is what iwconfig said, not a user-mode throughput measure ...
the audio worked even at 1260m, where the test range ended, though it
was very easy to stall by obscuring the antennae)

The ears down results on the second unit are:

200m, signal -71 dBm, noise -85 dBm, rate 5.5 Mb/s, all okay,
400m, signal -79 dBm, noise -85 dBm, rate 2 Mb/s, all okay,
600m, signal -84 dBm, noise -85 dBm, rate 1 Mb/s, some ping loss.

The iwconfig results on the first base unit are:

400m, signal -85 dBm, noise -89 dBm, rate 11 Mb/s,
600m, signal -87 dBm, noise -89 dBm, rate 5.5 Mb/s,
1260m, signal -90 dBm, noise -93 dBm, rate 1 Mb/s.

The ad-hoc setup sequence was:

# /etc/init.d/NetworkManager stop
# iwconfig eth0 mode ad-hoc
# iwconfig eth0 channel 10
# iwconfig eth0 essid foobar
# ip addr add 10.1.0.2/24 dev eth0
# ip link set eth0 up

I'm sure these units would perform very well if stuck on a tower ... but
I agree that isn't their purpose.  An antenna socket would be great!
;-)

-- 
James Cameron    mailto:quozl at us.netrek.org     http://quozl.netrek.org/



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