Set antennae Gain to 17 db
This together with placing the RB low down (about 2 feet off the ground) has reduced the signal sufficiently.
I have a new challenge though:
How to gain access to the RB from the main office (about 50M away) via the LAN cable connected to WAN / POE port?
So that staff can change the wifi key from the main office without having to physically go the the coffee shop...
get a wireless cpe to point on it and get access via wireless.
make sure you have enable the mac-telnet on the wireless interface.