Hello
I'm running a scan on a crowded site (>200 people around, bars & food, several shops), with a dual-chain, 4dBi omni-antennas 2.4Ghz mikrotik AP. I get the following results (see attachment).
From the spectral scan, we are receiving levels between -49 and -60. Does that mean that
1) there are several devices (Access points, ovens, alarms, whatever) which are polluting RF environment to a "real" floor of -50,-60 ?
2) That anyone with a -70 signal connecting to the current AP with current conditions will have horrible interference ? Will this be usable?

I doubt it would be useable.

To cope with this you'll need sector/directive antennas placed strategically if scenario allows for that.