tl;dr: Is there a optimal choice of 2.4GHz WiFi and Zigbee channels that will minimize the chances for interference between these networks?
Long version: I've been running my C7 successfully for the last few years connected to Ethernet on my local network with a collection of about 17 or 18 ZWave devices and about the same number of Zigbee devices.
As part of a LAN upgrade last week I put my ISP-supplied Zyxel C3000Z modem/router into modem-only transparent bridge mode and commissioned a newly acquired Netgear R6220 to serve as the router with 2.4Gz and 5GHz WiFi and connected to a handful of gigabit Ethernet switches serving wired devices like our local file server, client machines and media devices. The upgrade went smoothly and both wireless and wired devices were none-the-wiser that the LAN architecture had been reconfigured out from under them.
However, after a couple of days with the new router, I began to get flaky behavior from my Zigbee devices, and eventually every Zigbee device (except the leak detector in our basement next to the network cabinet where both the Netgear router and Hubitat were installed) dropped off the network. Experimental efforts to re-pair a couple of Cree bulbs failed, and I could see from the Zigbee device logs and graphs that none of the existing Zigbee devices were reachable.
Reading up (for the first time ) the Hubitat documentation page on Keeping your Zigbee Mesh Happy I was surprised to find out that Zigbee networks can be affected by the signals from 2.4GHz band WiFi radios. So I moved the Hubitat as far away as possible from the new router in our crowded basement without seeing any improvement. However, after switching off the 2.4GHz radio in the router, my existing Zigbee devices slowly but surely began reappearing, confirming the theory that WiFi signals from the new router were fubarring my Zigbee mesh.
Running 2.4GHz WiFi is essential for our network since we have a number of legacy 802.11 b/g devices that we have to support. Both the old and new WiFi routers were running their 2.4GHz radios on Channel 11 to reduce interference with our microwave oven and wireless landline phone handsets. And my Hubitat seems to have chosen Channel 20 for its Zigbee radio. But is there a better choice of 2.4GHz WiFi and Zigbee channels that I could make manually that will minimize the chances for interference between these networks?
I feel for you.
I set up a new Deco mesh a few months ago and things went wonky for my ZB network.
To compound that I installed a 10kW solar system and the inverters all use ZB to connect to the management hub.
There is not a lot you can do except experiment.
Use a WiFi analyzer on your phone and find a spot with little overlap for ZB channels 11, 15, 20 or 25.
I was on 20 and had to move to 15 as some of my ZB device would fail to even join after they went funky. I was just having issues again so I let my Deco mesh pick it's optimum freq and then moved away from that again. I also ran the Settings | ZigBee Details | Scan Channels to make sure I was not in a crowded ZB channel in the neighbourhood.
I had to rejoin about 50% of my devices as they don't all come back, even after 24 hours.
General rule many of us follow is 2.4Ghz Wi-Fi on channel 1 or 6, Zigbee on 20 or 25. (20 may be problemmatic on C8, but you have a C7 so 20 should be fine).
Unless you've actually seen significant interference w/your microwave and phones, I'd move Wi-Fi to 1 or 6...even if there is a little interference, how often do you run your micro or have long landline conversations? I had land-line w/wireless for years in the past along-side my Zigbee mesh and never had any issues...
You know the current setup isn't working, I'd change the Wi-Fi and Zigbee channels to move them apart and then see if you end up getting the intereference you were trying to avoid w/the micro and phone.
Also - make sure the new router is using 2.4 wi-fi 20mhz channel width, not 40mhz.
It sounds like your new router is using wide (40Mhz)channels for more bandwidth. I would verify that your wifi is using 20Mhz channels. Also, you could try putting wifi in channel 1 if you feel like you need the extra bandwidth of 40Mhz channels on your 2.4Ghz wifi.
In theory, chanel 11 with a standard 20Mhz channel should coexist well with Zigbee channel 20. My Hubitat also uses channel 20 and I keep my Wifi on channel 1 and 6 usually (I have 2 APs) but I've used 1 and 11 without issue as well until my neighbor moved in and saturated the channel 11 with his stuff.
It gets worse. They don't only pick their own channel... They almost never choose 1, 6, or 11, so they'll drop a 40 MHz signal on channel 7 and interfere with the entire 2.4 GHz band. I've managed to make them work, but I wouldn't buy them again.
They're not building their Deco mesh routers with zigbee or Thread in mind. They want their customers to have a really good WiFi experience when they automate their homes using TP-Link WiFi switches/dimmers/outlets/bulbs etc.
Yeah, I get why they are doing it, but I imagine these devices in apartment buildings, trashing the Wi-Fi of everyone within range of their 40mhz high power channel 7 machete...
My Deco does not automaticaly optimize but it does check the network status.
You have to trigger the channel update it in the app as it will suggest to you optimization may help.
Thanks to everyone for the info and insights and especially those helpful radio band charts!
@dnickel Can you recommend a specific Android app that's a good tool for this?
No, but I do have a couple of always-on-AC Zigbee devices that are doing yeoman duty as repeaters.
Unfortunately I have experienced interference between an old iPad we use as an internet radio player and the microwave - maddening to have the news or music drop out while you're cooking - which is why I moved our 2.4GHz WiFi onto Ch 11 in the first place.
I did not even know there were 20/40MHz choices for WiFi radio bands - that option was not exposed in our original router but I will go hunting for it in the UI of our new Netgear 6220. Our legacy WiFi devices do not have the need for high data rates so that would be a perfectly acceptable tradeoff.
) the Hubitat documentation page on Keeping your Zigbee Mesh Happy I was surprised to find out that Zigbee networks can be affected by the signals from 2.4GHz band WiFi radios. So I moved the Hubitat as far away as possible from the new router in our crowded basement without seeing any improvement. However, after switching off the 2.4GHz radio in the router, my existing Zigbee devices slowly but surely began reappearing, confirming the theory that WiFi signals from the new router were fubarring my Zigbee mesh.
