Access Points -right ontop of each other-

[mobiledynamics]

3x3 Omni Access point on wall.
On the same wall, just 4 feet away, I need to install a - directional AP- pointing to a very specific spot.

As long as one is on channel 6 and the other is on channel 11, will this be a issue of them causing backscatter, interference, etc

 

[Trip]

First thing's first. If you have to stick to 2.4Ghz for everything, you definitely want the directional and omni APs on different channels, and you ideally want the directional AP pointing as close to 180 degrees away from the omni as possible, with as tight a broadcast cone as you can get away with to form the directional link to the corresponding station.

Beyond that, I would recommend deploying 5Ghz for backhaul and/or fronthaul if/where applicable. Inherently, you'll get way more usable spectrum, lowering co-interference and increasing total usable throughput and airspace.