nmcli dev wifi signal value is in what units?

[CaffeineAddict]

nmcli dev wifi

I have 2 wifi cards both operating on channel 7 (BSSID grayed out), one has signal strenght of 84, another one has 62.

Q1: What is this value? is it dBi value or some percentage or something else?
Q2: Do my 2 cards interfere with each other since both are up, connected to same gateway and on same channel? (and ofc. close to each other 0.5 metters)

 

[Thunderpants]

1) Normally WiFi signal strength is measured in dBm (decibel-milliwatts) in the range -30dBm (perfect signal) to -90dBm (unusable) but in this particular case it looks more like a comparative percentage of some undefined maximum value (probably -30dBm).

2) Signals from 2 cards in close proximity and operating on the same frequency could interfere with each other.