@Bruce, thanks for the reply.    This is actually a large church site with no one present on the day in question but it's OK, I suppose.  We have a few legacy non-5G users and some legacy IoT devices using 2.4GHz on active days, but almost all serious WiFi connections are in the 5GHz range.    We only have 2.4GHz running for backward compatibility for a very few connections.  I have identified a large inside utility transformer on the radio coverage periphery of the first AP so that's probably the culprit for the interference I found but, nevertheless, I am not seeing any significant interference on the 5GHz band anywhere on the campus. ... View more

Thanks for the reply.    Out of 41 various MRs on this site, I could only find 2 that were showing this much non-802.11 interference and only on the 2.4 GHz channels.  However, almost all real usage is on 5 GHz channels so we've not had any usage complaints recently.   It's not practical to change the channel assignment right now due to adjacent usage.   I'm going to do some serious investigation for 2.4 GHz interference sources to see if I can locate a cause. ... View more