Hi, initally we'veisntalled the AP at the ceiling of my office. Then we've performed several tests, with:
Channel: auto
Transmit power: auto
Radio: auto(2.4 and 5Ghz)
Result: Dismal range
We've tried several combinations and obtained the same result. So we've decided to remove the AP and installed it outside, under the awning and we have it installed wall mounted. The signal however has not improved.
I'm here in the Philippines, I own and operate a two-storey transient inn, with 8 rooms, and the signal from the AP could hardly reach the second floor.
We have also tried your your suggestion and used a mix of different devices, but yielded the same result.