>>18499>>18516>>18517>>18519Pretty standard regulations are 1W EIRP for omnidirectional output and 4W EIRP for a directional antenna. In reality you can do whatever you want because it's Wifi and nobody gives a soykaf . If you have large or obvious antennas then you'll have problems with mentally ill people who believe the antenna is hurting them, and in those cases it's important to stay within regulations.
It's not good or practical to have one high power access point for the whole neighbourhood because every station would be talking over the others. You want a lot of lower power APs all connected together with hardlines. Operate them in WPA2-Enterprise mode with a dummy RADIUS server set to accept any credential. This way users of the community wireless network cannot snoop on each other without cracking the user's session key.
Sensitivity of your transceiver is more important that a big output power.