Should we consider removing most microwave ovens?

[david_henderson]

We are a K-12 school district who will be installing a Ruckus system this summer
It will consist of 2 Virtual SmartZone controllers and 400 R710 access points
Our environment is fairly high density and the number of personal and district owned wireless devices on the network will only grow. In the next few years we could even be looking at 1:1 where every student 4-12 is given a district issued device, most likely a Chromebook.

In the next few weeks my department is going to do a district wide inventory of microwave ovens. At this point we are guessing that teachers in more than half of the classrooms have brought in their own microwave ovens. We could be talking 200 or more microwave ovens district wide.

I know that dual band devices will likely join at 5GHz but in high density situations I have read that about 25% of devices will join at 2.4GHz in order to best utilize all the available bandwidth.

Should we be looking to remove most of the microwave ovens in the district and just provide a few in each building in order to minimize interference in the 2.4GHz band?

[lukas_josuhn]

In my opinion: no. If there is interference by microwave ovens: replace them, because they're broken! In my expirience a fully working microwave oven won't affect W-Lan (on 2.4 GHZ) at all:

I took 2 microwaves (700W each), put an iphone in between those two devices and started a speedtest (Speedflex-App). The AP had a wall in between.

Then I turned on both microwaves. There was no decreased thoughput. I tried this with channel 1, 6 and 11.

Keep in mind: those microwaves use a lot more transmitting energy (700W against 0,1W) so even if a extreme small ammount of the energy would be left out of the case (e.g. more than 0,1%) it would be more than an average AP and would fill out a channel.

[david_henderson]

I have AirMagnet so would a better approach be to go to each classroom with a microwave, launch AirMagnet, stand in the middle of the classroom, turn on the microwave and see if it throws off signal in the 2.4GHz band?

[john_d]

I remember back in 2004 when I was setting up my very first 802.11b wifi network, turning on the microwave would actually knock out the whole wifi network.

But now, even with my microwave on, I see zero degradation in 2.4GHz performance compared to my microwave off.

I have no idea if that's because my Linksys AP back in 2004 sucked, or microwave ovens were noisier back then, or some combination of those two factors, but in my experience, a lot of mythical sources of wifi interference don't really pose an issue these days. 


I wouldn't bother getting rid of the microwave ovens unless you genuinely see 2.4GHz interference correlated with microwave oven usage. I'm assuming based off 400 APs for a school district that 2.4GHz will be pretty crowded for you in nature, so you will almost certainly be relying primarily on 5GHz for your capacity. I wouldn't be very concerned about 2.4GHz performance at this point, or the load-balancing utility of 2.4GHz.