I need to add a wireless router or access point (and probably some high-gain antennas) for adding wireless N network access to our shop at work. Our shop is in a large factory and has lots of things that can probably interfere with the Wireless N network (machines, CNC machines, welders, etc). This device will be used to provide wireless access to our main network, so it can be an AP or a router.
So, I'm looking for something that's probably a Wireless N (don't need AC right now and probably won't for a few years yet). But it needs to be powerful enough to combat the EM fields and interference the machines put out. It isn't that high, but they will affect the transmission and coverage for sure in some way. The machines don't really transmit any radio frequencies, but they have large motors which I think can cause EM interference and thus affect the coverage output by the antennas.
We have a DHCP server on the network (which is part of our main server), so the access point/router does not need to have DHCP or NAT or any firewall installed since our main server takes care of these tasks anyway (and our hardware firewall as well). The approximate coverage area would probably need to be about 100 foot radius. We will be running a dedicated CAT6 cable between our server/switch and where the wireless AP/router will be placed, so the interference there should be minimal if at all. I'm just concerned about the coverage from the wireless AP/router to the clients which will be fairly close by (within 50-100 feet of the device).
One requirement I do have is that it needs to have removable (and upgradable) antennas. I don't care much for the internal antennas, and want this option in case we need to attach multiple antennas in other areas near by for better coverage.
What is the best router/AP I can get for this application? My biggest concern is not speed, but range given the fact it is going into a factory environment where lots of machinery is present.