We have a customer that requires 100Mbps down, 15Mbps up at 12 different locations. The max distance from the AP is 4.005 miles. Is it possible to service all 12 sites? We know 12 sites would not require 100% all the time, How many could we service using one AP.

You could probably get away with 6 customers to one 3000 on a 40Mhz channel on a NON-DFS channel. Otherwise, you will run the risk not having enough capacity available or frequent upload issues on DFS channels.

I really comes down to how often they each need to max out their connections, and how likely that will be all at the same time.

If (for example) these are 12 water pumping stations with the occasional telemetry and meter readings transmitted — you’ll have zero problems doing this. On the other hand, if this is (just for example) 12 banks which need to synchronize their daily transactions, and they do it all at 4:01 PM every day, then all that data will bump into each other.

So – it largely will come down to
a) how much data they really need to transfer, and
b) how often (or how likely) it is that they will overlap each other.

Also - you need to take into account that a 3000 MU-MIMO can transmit data to two different SMs simultaneously. So, with 12 SM’s connected, it’s possibly that each of them may be ‘paired’ with 6 or 8 of the others, and that can really help if they are downloading at the same time, and if the AP would otherwise be red-lining.

A 3000 has 600Mbps of throughput with a peak of 1.2Gbps (MU-MIMO)
Assuming each sight needs 100Mbps down at one time and a scheduler of 75/25 you could support 4 SMs per AP.