What geographic region are you in (country is good enough)?

Ok, Europe in general, led by Germany are much more restrictive in which frequencies can be used outdoors (only 5470-5725Mhz). 149 is not an option in your region (there's a great wikipedia page on all this if you are interested). In short you are constrained to the 5Ghz UNII-2c bands, so my suggestions would be to try Ch 100 or 116 (see which reports less inteference when in use). You are also further constrained by the requirement to observe DFS (radar avoidance). Now the EU have also opened up the 6Ghz band, so you might have much more luck with the newer EAP610-outdoors which can leverage this band. Love to hear how this goes.

  @lukass2000 @btx 

 

Please be aware that in Germany (EU), channel 48 has a max TX power of 200mW.  Channel 100+ have a max power of 1W (5x more power is a good thing).

 

Radar doesn't happen all the time and in my experience low power (relative to other signals, not absolute) is more often a stability issue than DFS.  If the 1W channels get you the kind of performance you're looking for and occasionally destabilize due to radar avoidance (DFS)...that's another problem as @btx alludes to above and you probably need to find a way to make channels 48 or lower work using directional/higher gain antennas etc.