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TonyT

Zigbee in a crowded RF environment - apartment?

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So has anyone noticed any issues with Zigbee in an apartment or condo complex which has lots of WiFi Access Points/routers?     (Zigbee sits right in the middle of one of three primary 2.5 Ghz WiFi "channels".  Yes, that's somewhat oversimplifying.)

Given a choice I'll use Z-Wave but if Zigbee devices are a lot cheaper well ...

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Ignore this posting.  I'm not sure how to delete a posting.
 

Edited by TonyT

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Hi @TonyT. Really good questions. Were you thinking that there would be interference with other Zigbee users? or even the WiFi?

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On 11/24/2019 at 11:17 PM, AYL_Alan said:

Hi @TonyT. Really good questions. Were you thinking that there would be interference with other Zigbee users? or even the WiFi?

I was thinking in between Zigbee and WiFi.     Wifi seems to be able to handle a crowded environment such as an apartment reasonably well bu then I tend to use the less crowded 5 Ghz band.    Also the bandiwidth consumed by non video and non audio sensors is very small.   It only takes a few dozen bytes to tell a switch to turn off or on.   So I'm not at all worried about multiple Z-Wave or Zigbee systems in the same apartment building.

So when it comes to Zigbee and WiFi.conflicts WiFi could "drown" out Zigbee or otherwise cause interference.

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Unless you put your WiFi router right next to your smart home hub then you are most likely good to go as they use different channels, (even if they are in the 2.4 Ghz band). I would suggest about 3 to 5 feet of distance between the two. I have had to explain this to some of my family/neighbors after they had bought their smart hubs and had problems with devices dropping off of their WiFi, and there zigbee/zwave devices becoming unresponsive. Mostly zigbee as most zigbee devices are fairly small and for the most part are ran on small batteries, (motion sensors, door sensors, etc.) Plus zigbee devices that run's on battery does not repeat the signal. Where as zwave devices (which usually run on ac power, light switches and the like) do repeat there z-wave signals, so often as not, go further with less problems.

Edited by Larry Underwood
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On 11/27/2019 at 2:01 PM, Larry Underwood said:

Unless you put your WiFi router right next to your smart home hub then you are most likely good to go as they use different channels, (even if they are in the 2.4 Ghz band). I would suggest about 3 to 5 feet of distance between the two. I have had to explain this to some of my family/neighbors after they had bought their smart hubs and had problems with devices dropping off of their WiFi, and there zigbee/zwave devices becoming unresponsive. Mostly zigbee as most zigbee devices are fairly small and for the most part are ran on small batteries, (motion sensors, door sensors, etc.) Plus zigbee devices that run's on battery does not repeat the signal. Where as zwave devices (which usually run on ac power, light switches and the like) do repeat there z-wave signals, so often as not, go further with less problems.

Yup, I hear you on the separation between the WiFi Access Point/router and the home automation hub.

When I run a WiF4i analyzer app on my tablet I see that multiple explicit WiFi channels are grouped into three "bundles of channels".      So when I looked at a Zigbee page a few weeks or month ago I saw the default Zigbee frequency being smack in the middle of the third commonly used WiFi bundle of channels.    Of course I can't find that web page or diagram now.   Here's an article I just found that goes into lots more detail.   https://www.metageek.com/training/resources/zigbee-wifi-coexistence.html    Which I hadn't realized you could do but then I haven't yet purchased a hub.    So now that I know this I will configure my home automation hub to use a channel in betwen the Wifi "bundles of channels".  

I should also add that I have my amaterur radio license so I'm always interested in exactly how RF is being used and I'm well aware that the public bands can have interference.   For example a new radar system in use at some military airports totally broke one particular neighbourhods garage door openers.  Turns out the developer chose some cheap foreign garage door systems that were not well built and were using frquencies not authorized in North America for such use.    Fortunately as this was still in the warranty period the developer had to replace several hundred garage door systems.   Oh well.

Edited by TonyT

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To add to my previous reply, the diagram I found in the past showed that Zigbee channel 23 or thereabouts, was the default Zigbee channel.  It is right in the middle of the third 2.6 Ghz WiFi "bundle of channels".   Which the metageek article I linked to above doesn't mention the default Zigbee channel.   As I don't yet have a hub I can't test all these settings.   If that is the case then in a crowded RF environment, ie a condo/apartment complex, there is bound to be interference of some sort.   That article also states many Zigbee devices don't support channel 26 so it would appear that channel 25 is the best option.    Also that article really doesn't talk about the condo/apt scenario either.

So to summarize the metageek article Zigbee channel 25 is recommended as it has the least interference with WiFi.  Now if that works in the real word, ie you folks, is another matter.  And the Smart Home hub, with the Z-wave and Zigbee support should be placed 3 or 5 feet from a WiFi Access Point/router to reduce chances of interference.

 

Edited by TonyT

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Thanks but I had already watched those.   I did rewatch them just now to ensure I didn't miss anything.  Brian does a good job with the basics of the topic.   I have my amateur radio license so I have some practical knowledge of some of the radio interference issues.    But I was looking for tips from a more crowded environment such as where I live which is a wood frame condo.  

I'd also like to change the Zigbee channel in my SmartThings V3 hub but it appears that's not possible.  Hey, us geeks like to play with such.  Sure, sure, give us the warning screens but let us shoot ourselves in the foot if we want to.  <smile>

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Yeah so SmartThings doesn't let that channel change on the ZigBee front.  You're absolutely right there.

That's actually why they use that channel way out there (I think it's 25), but channel 11 WiFi can still get in there and be frustrating.  Where I live right now though, in general, I'm not finding interference with my own in home WiFi and I'm also not finding my neighbours doing enough damage.  It's still something that I agree...warrants a bit of playing!

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