Even at maximum allowed tx power? Two of these should do 1km LoS easily at 90-150 mW: https://www.amazon.com/TP-Link-Directional-Parabolic-Connector-TL-ANT2424B

Even at maximum allowed tx power? Two of these should do 1km LoS easily at 90-150 mW: https://www.amazon.com/TP-Link-Directional-Parabolic-Connector-TL-ANT2424B/dp/B003CFATOW https://www.amazon.com/TP-Link-Directional-Parabolic-Connect... Of course, more power, more range (but also noise, so in reality you don't want more than ~200mW with standard routers) I used one of them to get a good 54Mbps connection with an AP ~400 meters away (5th floor to 2nd floor, only some treetops between). And that's basically the antenna just picking up the unboosted signal from the router (Linksys WRT54gs @ 85mW iirc)