" 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.


That is what the moonbounce operators do, but with more antenna gain!!

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

Again moonbounce is not uncommon in the 13cms band.

Jeff