Delivery-date: Tue, 12 Dec 2006 20:25:30 +1100
Date: Tue, 12 Dec 2006 20:25:29 +1100
From: James Cameron 
To: devel@laptop.org
Subject: initial rural range test
Message-ID: <20061212092529.GA22105@us.netrek.org>

G'day,

I've three BTest-1 units, running olpc193_A54.zip from Mitch.  I did a
quick test this afternoon using a WOAP54G access point mounted on a step
ladder on a remote farm.  The access point antenna was 2m above the
ground.

I carried one unit (QUOZL 1) on a walk.  I only tried three positions:
200m, 500m, and 900m away.  Operating position was ears up, with me
standing up.  I'm 186cm or so tall.  The terrain is lightly undulating,
as can be seen in the photographs.  I made sure I could see the step
ladder.

I was able to get perfect operation at the first two positions.  Beyond
400m the presence of vegetation between the laptop and the access point
began to matter.  At the 900m position, the network name was selectable
on the user interface, but association did not succeed.

I don't believe anything significant can be drawn from these results at
this stage, because I don't have a baseline to compare them against, and
the access point is an unknown.

Brief pictures ...

http://quozl.linux.org.au/olpc/2006-12-12/

(The start of the test was an ssh client connected to mpg123, playing a
long music podcast so I'd enjoy the test more, while pinging at one
second intervals.  The ssh stream involved a lot of buffering, so it
wasn't a useful indication.  The ping was most useful.  Later after
losing association and regaining it, I tested with flood ping, which is
very useful for displaying the effect of buffered retransmitted packets
... the line of dots grows on loss, and recedes on gain.)

Things I'm yet to do ...

- try the other two units, to normalise the test,

- monitor received signal strength on laptop (is this available
  anywhere?),

- monitor received signal strength on access point (OpenWrt, already
  know how to do this),

- map signal strength by GPS coordinates, seating position, laptop
  antenna deployment mode, EBook configuration,

- map throughput,

- test ad-hoc mode (waiting for availability).

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