i am using tplink clients and seems to max out at 9-10 with latency going 600 plus and frequent drops. ccq varies gr8ly betn 15% to 70%. LOS clear for all clients. Distance not more than 2000 mtrs. Client antenna approx. 12 dbi. Routerboard 433ah with Compex a/b/g cards. Sectors 120 deg and 18dbi. Height of tower 130 ft above ground. Bandwidth given to clients varies from 256 kbps to 512 kbps.
I have a longish firewall rule dropping ports from 1 to 60000 which improved things somewhat but dunno if its right to use all the time. Customers have internal Wifi routers connecting avg. 5 computers/laptops in their premises. So number of simultaneous connections r on the higher side may be 40+ for each given client.
I am fedup sometimes thinking wireline was better than this.
S.th. with your installation is very bad. 9-10 is a lightly loaded AP in our installations. We've RB600 with 3 Sectors in
5GHz + 1 Sector in 2,4 serving 100 customers without problem. Typical Customer is limited to 3MBit/383kBit.
Clients are all RB.