[jacquesm]

I had a pretty nasty wifi problem here recently and it took me forever to track it down to a forgotten Zigbee dongle that was broadcasting at its maximum power to find all those non-existent devices. It made several WiFi channels completely unusable. Pull the dongle, problem gone. Just in case it helps someone else.

[nullify88]

If you need a tool to diagnose situations like this, the Metageek Chanalyzer or perhaps a SDR with similar software can find such interferences.

[slowmotiony]

No way to do it from a regular laptop I suppose?

[nullify88]

Actually A while ago, it was discovered Atheros ath9k and ath10k based wifi cards have a spectrum scan feature. There was some work in reverse engineering the data format. I'm not sure if theres been similar developments for recent devices.

https://www.bastibl.net/ath9k-spectrum-scanning/

[wkat4242]

You'll need a wi-spy dongle, SDR or something similar. A standard wifi card won't identify any interference it doesn't recognise as a wifi signal.

[nier]

SDR stands for software-defined radio. Goes best with a software-defined antenna.

Source: https://en.wikipedia.org/wiki/Software-defined_radio