Zigbee (ConBee) and WiFi Interference

Hardware
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Hope this experience helps someone who may be having issues. Sorry if it is a bit long but want to paint the right picture.

I have a ConBee using native ZHA integration to HA. It uses the deconz communication protocol but I am not running deCONZ & Phoscon apps except on a Windows PC when I need to change config parameters or do updates to the ConBee I’ll plug it in there and bring it up.

For some time I have been working with developers battling issues with the zigpy/zigpy-deconz component. At this point they have pretty much re-written the entire component and done a great job on it. One of the things that kept coming up was a lot off issues with devices going offline or becoming uncontrollable. One of the developers had a thought about radio interference with WiFi and asked if I could run a USB extension, which I already did. The question had me think about all my WiFi disconnections my router was experiencing though. Did some research and found the ConBee is by default on 2.4Ghz Channel 11 which overlaped into my router settings, not a very good thing.

Soooo… I pulled the ConBee and stuck it into my Windows PC and using Phoscon set the channel to 25 then put it back in my NUC, of course using appropriate shutdowns and startups for the system. The ConBee fortunately will stay where you set it even when removed from the USB port or powered off. Using a WiFi analyzer app on my phone I found a good spot for my 2.4Ghz WiFi control channel, used 7 in my case, and even with the bandwidth needed for 40Mhz it is still away from the ZigBee channel.

The result was much more than I thought… Many of the ZigBee issues cleared up, still some have a little work to be done but not because of radio interference. My router log is clean as can be, no more disconnects and reconnects every few minutes on the low band WiFi like there was.

If you are having ZigBee issues, not just with a ConBee, go check your router logs for WiFi device disconnects. You will also see WiFi issues in HA on the information screen if it is integrated to things like OSRAM Hub, WiFi connected TV’s and Reciever’s etc. that are experiencing WiFi network disconnects. If you are seeing these disconnects frequently try moving the ZigBee radio channel (if you can) and the router channel as far apart as you can. A WiFi analyzer app on your phone helps for the router setup to find a clean channel spot. Don’t use “Auto” channel select on the router it does not know about the ZigBee because they are not the same protocol but they do interfere with each other. I also use a USB extension to keep my Aeotec and ConBee away from each other and my NUC.

If you are having issues hope this helps, also hope this helps prevent issues for new setups. ZigBee and WiFi interference is a very real thing as I found out.

10 Likes
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Great post!

I run Zigbee channel 25 and 2.4GHz wifi on channel 1. Works excellent.

I can recommend the usb extension cord as well. But it is more to do with signalling issues with the computer than WiFI issues. Might be different with the Conbee2

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I’ll just leave this here for anyone who thinks that Zigbee Channel 11 and 802.11 b/g/n 2.4Ghz Channel 11 are the same thing.

ZigBeeChannels
ZigBeeChannels693×123 20.7 KB

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Thanks for posting the channel chart I used that to figure out where to setup my Zigbee and WiFi. I should have posted that link as a reference thanks a million for doing it.

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Used the same process with my Xiaomi gateways. as they were fixed (luckily) near the end of the zigbee channels) i moved WiFi to channel 1 and it has been perfect for well over a year. no drop outs or unavailable sensors

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You’re very welcome - I knew exactly where I had it bookmarked because until I bumped into that write-up I just assumed the ZIGBEE \ 802.11 channels were same same and i couldn’t figure out why I kept having issues on channel 22! :slight_smile:

I was in a rush earlier and forgot to say - Great post!
You actually reminded me that I still had a few APs on auto channel and when I looked - they were totally flipped to a channel that was conflicting with my zigbee mesh. So, Thank YOU!

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I have been doing quite a bit to get my environment totally stable since posting this and have put together some easy to reference notes so here goes. Maybe they should be added to the official documentation but not my decision.

Zigbee and WiFi Interference

The 2.4 Ghz band is shared by Zigbee and WiFi and interference can occur. The channel settings for each should be set to provide as much separation as possible to avoid this interference.

WiFi and Zigbee channels are not the same, WiFi Channel 11 is not the same as ZigBee Channel 11 as shown in the chart below.

image

For the US setting Zigbee to 11 and WiFi to 11 or Zigbee to 25 Wifi to 1 would be good choices for separation.

A WiFi analyzer app on your Smartphone will help find a good channel without interference as exampled. There are several good free ones available. Note that you will not see the Zigbee in the analyzer.

image

You will need to find and set the control channel in your router and do not rely on “Auto” configuration as most will not detect the Zigbee interference.

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You may or may not be able to change the channel on your Zigbee controller or devices so you will need to do some upfront research on what the channel settings are or how to find them and can they be changed.

Something else to be aware of is if you have multiple Zigbee hubs. Beside a Conbee I have a Lightify Hub and there is no way to manually change the channel or easily know which it is on. Hubs similar to this “find” the channel with least interference automatically at startup. Once you separated your WiFi and Zigbee on the devices you can control if you have other hubs you cannot control power them down completely for at least 15 minutes or so and then power them back up. Keep them at the furthest distance from each other you can. The hub should reset to a channel that works with the changes you have made. For best results get everything on to one Zigbee controller that you can manage if at all possible to avoid this situation.

5 Likes
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Another 2.4GHz interference source is USB3 ports. If possible, plug ConBee into USB2 ports. And anything plugged into USB3 ports may serve as emitting antenna for 2.4GHz noise.
https://www.intel.com/content/www/us/en/products/docs/io/universal-serial-bus/usb3-frequency-interference-paper.html has more info and also Google for ConBee bootloop issues.

1 Like
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I want to optimize the 2.4 GHz channels used for wifi and zigbee in my house.
I plan on using channel 1 and 6 for my 3 APs as best as possible and channel 25 for zigbee2mqtt to avoid inteference.
But at the moment I still have the Philips Hue bridge and Xiaomi gateway. Is it a problem to have all of them on channel 25 or will they intefere with each other?

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Honestly have no idea about running multiple Zigbee hosts on the same channel… from what little I know about how they work I’m thinking it will be fine but you will probably just have to give it a shot.

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I would like to be sure about it before starting changing the channels but anyhow I guess when choosing channel 1 and 6 for wifi the only real channel left is 25?

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I have a Conbee and an OSRAM Lightify Hub for Zigbee. I just checked my sniffer and it looks like they are both on the same channel and don’t seem to bother each other. I could be totally wrong and probably am but I think that Zigbee works a little more like Bluetooth in that the devices only care about what they are linked to and not so much the radio channel.

I won’t say I don’t have any issues but the ones I do have are probably more with the system than with radio interference. Occasionally a light doesn’t turn off or on when it should sort of thing but it is rare.

I’m back to all you can do is try it unless someone knows for sure. I did a search and found nothing.

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I also searched without result :-/
I hope you are right, otherwise it will be difficult finding enough channels.

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I have 3 accesspoints, each on a floor, configured as 1,6,11 … So what is best approach for zigbee channel?

Or should I change wifi on floors 1,2,3 to 1,6,1 so I can choose 25 for zigbee?

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I think you answered your own question with the best answer.

I totally removed wifi 2.4. I only have 5g at my house. Also solved any issues. And left me with fast wifi :grin:

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Ok, :wink:

Cant drop 2.4 yet, still some devices that don’t support it

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I want to change my setup to the same setup you are using; zigbee channel 25 and wifi on channel 1, but when I try to change the Zigbee channel from phoscon I get an error message stating it was “unable to change channel”. I am on a RPi 3B + Conbee (v1) USB Stick configuration… Why would I not be able to change the zigbee channel? Anyone had similar issues?

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I have no idea

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Probably a good question for the deCONZ forum…

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OK, moved to the “deCONZ Community”. :slight_smile: