How and where to install access points should not be treated as an afterthought.
July 31, 2013
Wireless networking is a regular fact of life today, but there are many potential pitfalls to the ubiquitous, routine install.
Here’s a look at some of those risks and how to avoid them.
1. Don’t ever put the Wireless Access Points (WAPs) on the same channel (unless you have a single cell architecture) if they are close enough to each other to create interference.It gets easier to find open channels when using 5GHz (for now until 802.11ac), but when using 2.4GHz ranges you must remember that there are only three non-overlapping channels in North America. These are channels 1, 6 and 11. Think of multiple WAPs residing on the same channel as being akin to multiple meetings going on in the same room. Splitting up the channels is like putting each meeting in its own room. It’s a good idea to use a wireless spectrum analyzer such as Metageek’s WiSpy to look at your environment and pick the right channels to use.
2. Know the polarization of your antennae.
For example, too often I see WAPs with bipole antennae laying flat in a one-floor home. Think of the antenna as if it’s holding onto a doughnut through the center of it. This is how the “Fresnel” zone acts within that type of antenna. In most of these antennas, the signal literally looks like a large doughnut radiating outward in a circle from the pole. If it’s laying flat, then the signal is mostly going up and down and not side to side. If you’re trying to reach an area on the second floor, then this can work. But if not, you’re wasting valuable signal. You should also keep this in mind when mounting your WAP, especially as these days many come without external antennae. Of course, there are dual polarized WAPs out there as well, and in that case you don’t really have to worry about this as much.
3. Don’t slap a WAP on the back of a TV or install it in a rack.
Try your best to avoid anything that can cause RF interference, like having eight Sonos systems piled on top of each other or even something as simple as a wireless Blu-ray player. You also want to avoid lighting fixtures, power lines, etc. A/C units, elevators, fish tanks, trees, and anything else with lots of metal or water must also be avoided as such elements will block your signal from getting through. Ideally, a WAP should be mounted at least a couple of meters away from any possible RF interference and in line of sight of what they’re to be connected to. Of course, in the real world designers dislike seeing WAPs and so do customers. That limits where you can mount them, but do your best to remember and consider the polarization and keep your WAPs as high as possible.
4. Don’t just use your laptop to test signal strength.
Try your best to test with the actual devices that will be used because each device has its own power requirements, antenna polarizations and other nuances. At the very least, use your laptop as well as some hand-held devices to monitor the difference. One of the best tests is to use an iPhone to connect. Apple hand-held devices are notorious for having extremely poor signal strength. This is probably one of the reasons they removed all wireless signal strength meters from their app store.
5. Don’t use the homeowner’s name or company name as their SSID.
This is like broadcasting to the world, “Hey this is my wireless network, now come and hack me!” There is no reason to do this and an integrator should explain the dangers to their clients if they insist on choosing easily identifiable SSIDs like their name or company. Also avoid WEP encryption at all costs, since nowadays it can be hacked in mere minutes. If a legacy device requires WEP encryption because it can’t handle anything else, use MAC address filtering and put it on a secure VLAN that allows routing only to the device it needs to talk to.