and you could check the advanced settings, AP isolation, if it is enabled, the clients devices cannot communicate

it could be DFS problem.

Is the WiFi hotspot outdoor? You need an outdoor AP, not a diretional antenna, antenna does not process signal. you can try TP-Link CPE, CPE210 for 2.4GHz WiFi or CPE510 for 5GHz WiFi

300Mbps is Physical layer maximum wireless speed. There are many overhead and data loss in the open air. The throughput(actual data transmitted) seldom exceeds 100Mbps, 100Mbps port is good enough...

danymarc wrote Are you sure no signal over 100 mts.? When I had my 5210 I connected from 778 mts. from iPhone4, iPad2 and Laptop, I'm not posting it's ideal, but 100 mts. come on, that line comes...

danymarc wrote this is what I would do open a Emulator here is the link http://www.tp-link.com/resources/simulator/CPE510/index.html and setup 510, the emulator will be your guide Emulator firmware...