Which way is up?

A recurring problem I face in dealing with wifi performance issues is not being able to relocate access points. Asbestos is a problem in many buildings and in some cases adding extra data cabling is so challenging it just isn’t worth it. But… that isn’t always the reason for things not being quite right.

When wifi was first installed it was expensive. It was also 2.4GHz only. You can stick a 2.4GHz AP in a corridor or communal area between several rooms and it will probably provide pretty good coverage. You have relatively few devices to connect. You want to cover as much of the building as you can, you have no money… what would you do?

So the AP is in the corridor, which isn’t ideal in most cases (a topic for another post). But that’s not the biggest problem…

Our original Colubris, and later some Cisco APs had an external omni antenna that could be turned by 90 degrees. So the AP could be mounted on a wall next to the data socket. A few vendors and models of AP later, we became an aruba site deployed the AP65 and then the AP125. These have built in antennas but they can be rotated to be the correct orientation when mounted horizontally or vertically. They may look a bit weird, but the design is really flexible.

The problem with this is it means we mount APs on walls next to the data socket, because that’s just what you do. When it comes time to replace the AP125 with something newer we bought the version with a built in antenna, just like before, only now it’s a down tilt omni antenna that’s designed to be mounted on the ceiling. It doesn’t flip round. Worse still the back of the later Aruba APs is metal. So when that gets mounted on the wall in a corridor it doesn’t provide very good coverage to the rear. It’s also putting far more energy to the floors above and below than is likely to be desirable.

We’re creatures of habit and once we know how something’s done, we’ll tend to keep doing it the same way. As a result even as new buildings go up, the APs with down tilt omni antennas get put on the wall rather than the ceiling.

Does it make all that much difference? Yes… it does.

In one building I worked on APs designed to be mounted horizontally on the ceiling were, of course, on the wall just above the suspended ceiling grid. They were nice and neat up there, nobody could see them. Unfortunately not many people could use them either and complaints were routine.

A before and after site survey showed that simply re-positioning the AP in the manufacturer recommended orientation significantly improved the coverage in nearby rooms.

We’re now stuck with APs mounted against the manufacturer’s recommendations in some of our buildings for good reason. You may find yourself in the same boat, and you have to make the best of it. However it’s always worth checking whether or not what you’re about to do still makes sense, even if it’s just the way you’ve always done it.

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