Somewhere on teh intarweb "Dr Zoidberg" typed:

snip

Doing testing with a couple of Cisco APs and high gain omnidirectional
aerials we've had them working over several hundred meters , and even
further with directional ones but that's on open ground. In a built up
environment it's unusal to get anywhere near that.

The world record for unamplified WiFi using off-the-shelf Linksys APs and
very large omnidirectional antennas is, I believe, over 280 kms.
--
TTFN,

Shaun.

"another academic failure.... trying to prove that your smart"
'blanking', nz.comp, 20 Dec 2007.