SmartThings Community

FAQ: Networking and Reducing Channel interference between WiFi and Zigbee


(Nigel Williams) #41

Hi everyone
I am here in UK and seeking advice on channels
I have 2 WiFi APs, the modem router on Channel 1 and additional AP on Channel 11.
The modem router is also using Channel 36 (20/40/80) for a 5GHz WiFi.

Having checked the STT IDE I can see the STT Hub is running Zigbee on Channel 20.

I am just about the migrate some of the Home Automation on a Hubitat.
Currently the Hubitat Hub is using Channel 16.

Before I proceed to start building out my additional network, does anyone have any advice on the CHannels currently selected?


#42

Once you get a chance to read this entire thread from the top and look at the pictures you should be able to select channels for yourself.

The 5 MHz band won’t make any difference. It’s just the 2.4 you have to worry about.

In this particular case, 16 and 20 May be too close together if you intend to keep running both zigbee hubs.

On the other hand, with your wifi set up the way it is it’s going to be tricky to find zigbee bands unless they are right in the middle. So it may just take trial and error, particularly if you’re going to be running two separate zigbee networks.

What’s the power setting on the Wi-Fi APs?


(Simon) #43

I don’t see an issue here. Wifi channels 1 and 11 are well away from bothe those zigbre channels and as zigbre is only 2 mhz wide channels 16 (wifi channel 5) and 20 (wifi channel 9 will happily co-exist.


#44

Zigbee channel 16 overlaps the sidelobe for Wi-Fi channel 1 and zigbee channel 20 overlaps the sidelobe for Wi-Fi channel 11. Because Wi-Fi is so much stronger than zigbee, you can get interference even in the side lobes. It’s kind of like when the microwave comes on and Netflix starts buffering.

It’s easy to avoid Wi-Fi channel 1 and it’s easy to avoid Wi-Fi channel 11. It’s just difficult to avoid both of those with two separate zigbee channels, which is why I said it might take some trial and error.


(Nigel Williams) #45

@JDRoberts thanks

To be honest I dont know what the Tx Power is on my APs.
I am using a stock Vodafone Connect Modem/Router firmware 5.4.8.1.291.1.30.1.32.1.2 for Channel 1 & a Devolo 1200+ WiFi ac powerline Firmware 2.2.0 for Channel 11.

I have now moved the Hubitat Hub some 10ft away from the Devolo now. I will look at the physical location of the Hubitat when things grow I think. I do have a spare Devolo Powerline so the hub can go almost anywhere in the middle of our 3-storey house.

If all goes to plan I will be migrate all the zigbee (and zwave) devices over to Hubitat in time.
Then linking the 2 hubs for stuff that is best on the STT.
The STT Hub as a bridge for the more complex integrations

This being said, the Zigbee Channel on the Hubitat will be more important than the Zigbee Channel 20 running on the STT Hub.

Can Zigbee be turned off on the STT Hub?
Does this make sense?


(Nigel Williams) #46

FYI
I have just spoken with another STT and Hubitat user who has over 120 Zigbee devices across both hubs.
He has them BOTH on CHannel 20 and has been working fine since Feb 2018!!!


#47

Interference depends very much on local factors, even the placement of furniture and your neighbour’s WiFi.

If what you have is working, great: stay with it. :sunglasses:

If you seem to be having issues like slow response, lost messages, etc, since ST doesn’t give us any network diagnostic tools you can start trying “best practices” changes like looking at channel numbers and physical device placement.