AT&T WiFi at McDonalds, etc

dold@22.usenet.us.com hath wroth:

>Maybe he was working from paper USGS Topo maps, which are NAD27, or at
>least, doing that often enough that he keeps his GPS set that way.

Yep. That's what he was doing. Most printed USGS maps are still
NAD27. They are sloooooooooooowly moving toward NAD83, which is
almost identical to WGS84. I've been told that their new satellite
based (SRTM) maps are going to be WGS84 based, but that's not official
yet. Meanwhile:
<http://education.usgs.gov/common/lessons/gps_questions_and_answers.html>

>> Anyway, many of the databases were generated from
>> Netstumbler logs, which locate hot spots in the middle of the road
>> where the sniffer was located, and not at its actual location.
>
>Point of highest SNR, IIRC, so unless you drove over the top of the
>antenna, it likely would not be "correct". I went to the effort of mapping
>the strengths in one of the available exports from NetStumbler to
>semi-triangulate the signal, but if you're in a car, that's kinda
>directionally biased.

I was thinking of building a rotating directional antenna contrivance.
It would record a series of vehicle positions and bearing (maximum
signal strength) lines, which would hopefully cross at the real
location. That's the way I do hidden transmitter hunts.

--
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