FAQ: Networking and Reducing Channel interference between WiFi and Zigbee

Continuing the discussion from [RELEASE] Keenect V1.1.0, pressure protection release:

Wanted to start a thread on best practices, tools and general discussion on wifi networking and channel interference…

I am using several Android apps to manage my network, but I am no RF engineer so it’s always good to hear from others on how they manage their networks. To get started, here is the diagram I’ve been using to limit the interference in my home…

source: http://fosiao.com/content/zigbee-and-wifi-rf-channels

Also, another interesting article, is this:

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Good diagram, but I think it might be misleading for the subject at hand. Although the Zigbee protocol is frequency agile, SmartThings’ implementation is not. Whatever frequency you are randomly assigned is what you got (which can be verified in the IDE, My Hubs). In my case, the hub is on Zigbee channel 15. Although it’s between channels of the 2.4 wifi band, because the signals are not zero bandwidth (typically 20 MHz), I still have to avoid that part of the spectrum on my router.

(Edited the reference to wifi channel avoidance; I misread the diagram first time around. :sleeping: )


:arrow_up: This.

The SmartThings hub is a very inexpensive device. Its Zigbee coordinator is pretty limited compared to more expensive devices. As @Mr_Lucky said, it cannot change its Zigbee frequency, either on the fly or as a user request. Whatever it was set to at the factory is what you’re stuck with. So, to be honest, “best practices” from a network engineering standpoint just don’t apply to a device of this type.

The best things you can do with a SmartThings hub to limit Wi-Fi interference:

A) put your smartthings hub at least 3 m from your Wi-Fi router. Also keep it away from metal.

B) whenever possible, put your Wi-Fi traffic on 5 GHz, not 2.4. And choose a 2.4 Wi-Fi channel which is the maximum distance from whatever Zigbee channel your SmartThings hub happens to be on.

C) don’t use boosted Wi-Fi in the 2.4 range

D) if you’re in the US, use boosted Zigbee devices when available. Most Zigbee home automation devices made in the US are boosted for exactly this reason. Also, replace batteries when they hit 50% instead of the more typical 20% to keep signal strength high.

E) if you can afford it, try to make sure that every battery operated Zigbee device has at least two mains-powered zigbee devices (but not Sengled, they don’t repeat) within range so that there’s always an option in routing. Zigbee light switches, in wall relays, and pocket sockets are good for this purpose. Remember that you are working with 360° signals, but signal doesn’t spread until it’s about eight or 10 feet from the device. So your best repeater might be a device one floor up or one floor below. But It can actually work better if the repeating device is also about eight or 10 feet left or right of where the other device is.

F) you can try alternative placements. As I’ve mentioned before, we have a Wi-Fi booster and if I put it on one wall in a room it kills all the ST Zigbee devices west of it. But if I just move it 90° to another wall, everything works perfectly. Sometimes doing as little as moving a device two or 3 feet in one Direction will make a difference. But this is all pretty much trial and error.

G) some more expensive zigbee coordinators use what is called “channel agility” and can change the channel they are using on-the-fly if there is too much interference. The SmartThings hub does not.

H) The Phillips hue bridge allows you to change its channel whenever you want. Your Wi-Fi router probably does too. The SmartThings V1 hub could not change its channel at all after it was manufactured. The SmartThings V2 hub can change its zigbee channel, but only if you do a factory reset and lose all your existing information, and the channel is reset randomly so you can’t specify what the new one will be and you might even get the old one again.

So there are a lot of things you can try, but Nothing guaranteed.

Short Answer

The best configuration is usually to make sure the Wi-Fi router and the SmartThings hub are at least 10 feet apart, and use Wi-Fi on channel 11, SmartThings on channel 11, and the Phillips hue bridge on channel 25. (See the diagram in post one of this thread – – Zigbee channel 11 and Wi-Fi channel 11 are about as far apart as you can get.)

Unfortunately, however, since it’s not easy to change the SmartThings channel and it doesn’t use channel agility, you may have to go through all the steps above if you’re having interference problems.


Well said, one other thought. While ST’s zigbee channel cannot be changed, for those with hue hubs it’s a real juggle, as we are dealing with two zigbee meshes, oftentimes sharing the same 2.4 range with many other devices. Luckily , the Hue channel can be changed…


I have very poor 2.4 Wifi Range in my house and have deadspots. This was really only noticable with certain devices like iPhones, iPads and certain Wifi hardware like RainMachine.

For this reason, I was forced to buy a Verizon Actiontec Moca Extender, which servers as an access point, a Asus Dual band 802.11ag router which allows me to use 5 Ghz (my FIOS router doesn’t support 5ghz, so I made that just a router and disabled Wifi on it). This along with some of my devices now able to use 5ghz has alleviated most issues. My Hue hub is on channel 15, my ST hub is on 20. However, both hubs and my router are all really next to each other. I could move them to my MOCA extender in the bedroom, but I like the current placement as it’s very central to the house, were as the MOCA extender is all the way in my bedroom towards to rear of the house.

This graphic is really helpful! I feel ashamed of myself that I didn’t research this much and just assumed that the channel numbers were consistent between zigbee and wifi. My ST is on channel 14, so I moved my wifi to channel 1 thinking I was creating space.

Things are working pretty well, so now I’m concerned if I move it back to channel 11, I’ll make things worse somehow. I think channel 11 is less occupied by my closest neighbors too, so maybe I’ll give it a test run this weekend.

Ha, I started thinking of playing againg with my set up, as recently I’ve got the CellSpot. Like you my ST zigbee is on 14, my Hue is on 25, my Fios Quantum router is on 11, but I have the guest network enabled. I’ve got the CellSpot to use it mainly as the guest network on a different channel. Verizon doesn’t allow me to change the channel on the guest network. So I hope this move will strengthen my set up.

Guess I lucked out, mine is on 24 so I use 1 and 6 for my two AP’s.

Originally I had all kinds of issues with lights dropping off, then saw this issue, one of my AP’s was on 11, moved it, bam everything worked!


Any advice on zwave 900mhz interference? For the life of me I can’t figure out why my zwave devices only work if they are RIGHT next to my hub. Everything worked fine at first.

Old wireless phones used 900Mhz bands. Honestly not thinking of anything else off the top of my head that did, but I know there are other things. Maybe wireless irrigation controllers and stuff…

Alarm system, any old wireless devices or just thick walls and ST hub positioning. I have zwave repeaters every six feet or less throughout my house (all my switches and most of my outlets are z-wave), so I don’t have any issues.

Wow thanks All. There is a pocket park right in front of my house with irrigation. I just emailed my HOA to ask is they installed a wireless controller.

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Some baby monitors and weather stations can also cause zwave interference. Basically anything in the 900 band in the US.

You can also lose signal if there’s something strong enough on a different band. This is like when you turn on the microwave and Netflix starts buffering. It’s not that your microwave is using Wi-Fi, it’s just sending out a super strong signal and it creates bleedover noise in a lot of bands. This is exactly why RF devices are regulated. But it is possible that somebody has hacked some kind of device near you and is sending out unregulated signal that’s causing interference. Also, a poorly installed or damaged satellite dish downlink sometimes causes problems with RF leakage.

As far as the park’s irrigation system, that would be pretty uncommon just because of distance. Zwave is a low-power protocol. You can have two neighbors in an apartment building each with a Z wave hub they won’t interfere with each other.

So more typically you’d be looking for something within your own home on the same frequency, again, like a Baby Monitor. Or something within a block that was high power even if it was on a different frequency, like a Neighbor’s satellite dish.

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It may also be a faulty hub or even a mesh issue. Have you tried running a zwave repair?

May I ask how do you know the Zigbee channel of your hub?

It’s in your account information in the IDE.

  1. click on the community link at the top right of this page

Two) click on the “developer tools” link at the top right of that page.

Three) sign in. This will bring up your account information.

Four) choose “my hubs” and then pick the hub that you want to check on

  1. you’ll find the zigbee information about halfway down.

Cool! Thank you!

Another thing, what do you find when you sniffer the Zigbee transmission? It that possible that the transmission has a regularity pattern when the environment is stable?

Do you think I should I change my Wi-Fi channel? My Zigbee hub is using channel 14, and at the moment my Wi-Fi is on channel 13. Would it be interfering? There’s a lot of neighbours traffic in the lower channels, but I can change channels if it would be better.

WiFi should be on ch11 or 6, in that order of preference. Assuming you are in the US. You want Ch1 as free as possible as that’s where your Zigbee ch 14 is located.


Zigbee 14 overlaps the high-end of WiFi 1, but isn’t anywhere near Wi-Fi 11 or higher, so you should be fine as you are. :sunglasses: