On Sun, 26 Apr 2009 17:57:18 +0100, LR <lrme@privacy.net> wrote:

>I wondered if it recorded the peak value of each AP at each location but
>needed a high signal level, say -50dBm, for at least one AP to provide
>some form of reference.

I think it's dumber than that. I've been trying to mentally reverse
engineer what they're doing to produce my bogus results. After
tossing all the complexicated bad guesses, I have yet another
guess(tm).

Methinks, that they're averaging *ALL* the signal levels at any given
point. They measure the signal level from the assortment of hot spots
heard, but only record the average value. They also might do some
data smoothing with adjacent locations. In a perfect environment,
with only a few AP's, that would produce a very usable result. It
worked fairly well inside my palatial office, where I could only hear
4 AP's. However, when faced with my outdoor environment, and a myriad
of AP's, the average value will be fairly constant. The result is a
uniformly constant signal level. Mehthinks this is highly clever, but
not particularly wonderful for all applications. It would require
data filters to fix the problem.

>Looking at your survey I would say you probably
>did your first check outside your home/office and recorded a low signal.

It's my home and you're correct. The results I posted was test walk
#4. Test #2 started inside my house, where I was close to two AP's. I
decided that this might affect the results, so I started test #4 from
the road level, so that everything was on equal footing. That made it
worse resulting in the uniform signal level.

>Have you tried doing your first check inside your office where there is
>a high signal level and then going outside for the next check?

Yes. I got a rather hot (red color) spot starting at my house.
However, it radiated to well over half the map, which isn't much of an
improvement.

--
Jeff Liebermann jeffl@cruzio.com
150 Felker St #D http://www.LearnByDestroying.com
Santa Cruz CA 95060 http://802.11junk.com
Skype: JeffLiebermann AE6KS 831-336-2558