Jeff wrote:

Your scheme is doomed to failure.

Although signal strength is proportional to disrtance it
is also affected to too many other things as well.

For your scheme to work both transmit and receive
antennas must be truly omni-directional with no
lumps in the polar diagram (not easy espicially
mobile). The terain must not cause any disturbance
to the signal (impossible). There should be no
reflections. The transmit power or receive gain
must not change. I am sure there are a few more
that I have not thought of off the top of my head.

Having said that such a scheme could give a very
approximate location if the data was analysed and
anomolous readings ignored.

Regards
Jeff

While it may be doomed to failure the value of the theory is sound and
it is one of the techniques that can be used to determine user location
of a cell phone except that the cell phone solution also have the time
similar to GPS so they can use time instead of field strength.

It is an interesting idea theoretically. You could plot circles on a map
from the relative signal strength value and centered on the GPS
location, then increase the circle sizes proportionally until they
intersect and this will provide a rough idea of the location. With more
locations it would be better and better, throwing out some of the
circles that don't fit. It will probably work if you live in one of the
plains states and have a very sensitive RF meter and lots of driving time.

Dale





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_ _ Dale DePriest
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