External 2.4 ghz antenna short range

I'm trying to get internet free from near by caffee stores ( 2 blocks away) but i'm not getting any signal only from few neighbors i have 2.4 ghz grid antenna tp-link with lmr400 cable 30 ft long and buffalo router hp g54 flashed with dd-wrt software ,i try tx power and on high and low still same thing does'nt go more then 1 block i dont know what i'm doing wrong i know this kind of antennas go for mile i'm only get 5 acces points and i live in the midle of the city please help

Thanks