When I use the Net Analyzer android app to look at WiFi signals, I see on channel 1 of the 2.4Ghz band a signal with a hidden SSID and a mac address of ff:ff:ff:ff:ff:ff. The strength shows -86dBm from a -100dBm floor and is much stronger than mine or any of the neighbouring WiFi signals compared to me sitting 2m from my own router with a strength of -45dBm.
On NetGear WiFi Analytics android app I see it with a strength of 0dBm
The signal is not encrypted and signal strength doesn't change.
I have turned my devices off, so I know it is not from me.
Would you say this is faulty equipment or a jamming signal on the channel one frequency?
With a reported strength of 0dBm that does not change, it may be from the NetGear WiFi Analytics android app itself. Perhaps sending out some discovery packets via broadcast (ff:ff:ff:ff:ff:ff) to evoke a response from idle wifi devices. I don't have any experience with that app though.