Interference by channel

[eagles-nest]

Hi

I'm looking for some help in interpreting the interference by channel graph on an AP.    See below. 

The Noise vs Channel seems straight forward.  However, what am I seeing in the interference by Channel graphs?  In particular what are the high blue lines on channels 1 and 7 saying and what are the red bars saying?  Does channel 7 have around -45dBm of interference and what does the percentage of just short of 20% represent?  What time period are these stats over and is there cause for concern here?  Channels 1 and 7 seem to jump out as very different from the other channels.

Thanks, Stuart.

[mbharti]

Noise is the RF energy which AP can not decode. 

Interference in 802.11 RF energy i.e AP can decode it.

So higher interference means there is another wifi device nearby on that channel.

Hope it helps!

[eagles-nest]

Thank you for the reply. 

However, I know that noise is external non-wifi energy and interference is wi-fi related energy.  Other AP's, smartphone hotspots etc.

What I'm trying to ascertain is specifically what the high bars on channels 1 and 7 are telling me and what are the percentage values related to.  On channel 7 the red bar is just short of 20%.  20% of what?  Are the values in the blue bars a point in time?  So is channel 7 seeing 45dBm of interference at the single point in time I looked at the stats?  Also, is it strange to see interference on channel 7 as opposed to channel 6 or is that an indication of something using channel 7 for wifi traffic? Channel 6 looks very clean in respect of interference.

Thanks in advance for any replies, Stuart.

[patoberli]

I think it means the following:
Blue bar = signal strength of the other AP
Red bar = the used up air time (load) on that channel