Jeff wrote:
Note that in almost all places there are legal limitations on EIRP
(Effective Incident Radiated Power). In plain English, the more
you narrow a signal, the stronger it becomes.

Since you did not say where you are, I'll mention the two places I
know for sure. In the U.S. WiFi EIRP is limited to 1 watt for
mobile/portable use (e.g. laptops) and 4 watts for fixed links.


Bear in mind that 2.4GHz is also an amateur band where no erp limits exist!!

Jeff



Well.. not all the 802.11b/g channels are in the amateur band, and even
there, there is a power limit (transmitter output power, though, not
EIRP), so you could conceivably fire up your 1500 Watt transmitter into
a 20dBi antenna and blast away.

There is the other rule about minimum power needed for communication,
though.