<OT> Wireless Access Point

[James Knott]

Peter L. Peres wrote:
> On Tue, 30 Sep 2003, Wil McGilvery wrote:
> 
> 
>>What I am wondering is if anyone on the list knows of a better way to
>>pinpoint the location of a wireless access point.
> 
> 
> There would be the trick of making the antenna directive and taking a
> bearing or two. You can do this using yourself (your body) as movable
> attenuator screen. Put the laptop on a non-metallic desk and slowly walk
> around the desk while keeping fairly close to the laptop. When the
> fieldstrength indicator dips you are cutting the main vector that ties the
> laptop to the transmitter. Keep in mind that there will be reflected paths
> too so there will be several dips. The biggest one is the one you are
> looking for.

I could make a certain comment about that, but I won't.  ;-)

However, often with microwaves, a reflected signal may be stronger, if 
there's something on the direct path to the source, that attenuates the 
signal.

> 
> This works because your body is mostly water, and 2.4GHz is absorbed
> pretty well by water (microwave ovens work at 2.4GHz too). The field
> strength indicator must have reasonable resolution for this to work (say
> 3dB steps or finer).
> 
> This trick works for most microwave equipment above 1.5GHz, including GPS
> up to a point. Do not try it with active radar though.

The principle is the same for all frequencies.  However, directional 
antennas are easier to obtain for the higher bands.



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