I wrote an article on meshing far apart APs, but it wasn't published external.
Our default mesh distance for ZoneFlex outdoor APs is 600 meters.
APs must both see each other with an RSSI of >= 25 on their wifi1 (5G) radios.
You can enter your ZD debug into the Log Analzyer on the Support Portal front page.https://loganalyzer1.ruckuswireless.com/Rowdy/
It will create a 3D map of your Root and Mesh APs. You can click on either node,
and then the Mesh Info tab, to check and see if both APs have sufficient RSSI. This
is similar to what TSEs can pull from your ZD debug with internal (Merlin) tool. In
this case, this AP, can see AP_1F:E5:10 at RSSI of 27 on channel 157, so is a good
AP: c4:10:8a:1f:cc:60 / 10.10.1.11 / fc00::1
Name : AP2
Mesh Role : ROOT AP
Neighbor MAC rssi/radio ch state adv depth reason last seen
c4:10:8a:1f:c6:10 13/11g/n 1 0 0 Tue Jul 8 01:31:11 2014
c4:10:8a:1f:be:00 27/11g/n 1 0 0 Tue Jul 8 01:09:11 2014
c4:10:8a:20:8d:c0 29/11g/n 8 0 0 Tue Jul 8 01:27:11 2014
c4:10:8a:1f:e5:10 27/11a/n 157 D 1 1 c Tue Jul 8 01:35:34 2014