Weird bug when bonded channels are inferior to main channel

I have been experimenting (ar750s / 3.100 / default US region) with different 5ghz channels and have noticed some issues:

When the primary channel is higher, then the noise level reported in luci overview or luci wireless often fluctuates to 0dbm:

1: select channel 161 with width of 80mhz. Every few seconds, luci reports 0dbm signal.
2. select channel 48 with 40mhz width. Every few seconds, luci reports 0dbm signal - not 100% reproducible though.

On top of this, channel 165 also has this effect whether it is primary or secondary channel as shown when using it with only 20mhz channel width.


  1. select channel 157 at 40mhz (bonds with 161) - there is no weird 0dbm issue.
  2. seledt channel 44 at 40 mhz (bonds with 48) - there is no issue.

So two things to take away:

  1. If the channel bonding is negative (ie. the main channel is higher than the secondary channels) there tends to be a 0dbm issue - it is most common with the higher channels.
  2. If the channel 165 is used as primary or secondary channel, there is the 0dbm issue. This is 100% reproducible for me.

Is this 0dbm issue tangible? It’s hard to tell whether this is actually causing any issues as the router seems to function ok despite it.