WSN 9791 frequency selection, and interference

[Garrett Cook]

The WSN-9791 indicates that it can operate on 11-24 channels on the 2.4 GHz band (I'm guessing USA is restricted to 11).  How do multiple NI WSNs in the same vicinity avoid interference?  Is there a way to set or determine the channel(s) that the network operates at?  For instance, with common 802.11 internet hubs they can be set to use any of those 11 channels.

Thanks,

Garrett

[Kevin_H]

Hey Garrett,

 NI-WSN Gateways operate on channels 11-24.  The numbering scheme in Zigbee is different than 802.11 and there is really no relation between the two. I have linked an image below that shows the differences between 802.11 and Zigbee channels:

 Note that this image shows 802.11 channels 1, 6, and 11, while the Zigbee channels shown are 11-26.  The channel the gateway operates on can be set from within MAX.

In addition, Zigbee channels do not overlap, so you can run a WSN network on each channel without fear of interfering with another Zigbee channel.  With 802.11, there are only 3 non overlapping channels (1, 6, 11).

Let me know if you have any other questions!

Kevin

[Garrett Cook]

The chart you posted is very helpful.  It looks like the last two channels (25 and 26) are very nearly outside of Channel 11 in 802.11 networks...but they cannot be set?  And would all the WSN gateways need to be set to different channels if operating in the same vicinity?

Thanks!

Garrett

Message Edited by Garrett Cook on 10-12-2009 03:51 PM

[Kevin_H · Accepted solution]

Hey Garret,

You are right that channels 25 and 26 are outside the 802.11 range, but they cannot be used for the same reason you can't go over channel 11 for 802.11 here in the US.  

Also, for gateways in the same vicinity, you must set them to different channels.  Running gateways on the same channel in the same vicinity will cause some problems for both networks.

Keep the questions coming!

Kevin