It's been a few years since I've played around with this so I'm not sure if times have changed.
When using AR7921 chipset (Alfa AWUS036NHA) on Ubuntu 20.04 I can see many networks using the following commands
airodump-ng start wlx00c0ca84d0f8
airodump-ng mon0
I've noticed all the VMxxxxx networks have a very low beacon count, perhaps 1 every 20 seconds (compared to e.g BT Broadband APs which seem to have a "normal" beacon count of several per second. The VMxxxx networks are Virgin Media home broadband networks- including the connection I'm legitimately using that is 6 feet away from me.
The rest of the networks have normal looking beacon counts. Has something changed/new technology in place that reduces the beacon count over the past few years or is the issue something else?
I can use the following command for half an hour on my VMxxxx network and find nothing connecting to it, even though I've got 4 different devices here using that access point (disconnected and reconnected them several times).
airodump-ng -d [APMACHERE] -c 6 mon0
Sample output after 45 minutes
CH 6 ][ Elapsed: 46 mins ][ 2020-06-13 17:34 ][ fixed channel mon0: -1
BSSID PWR RXQ Beacons #Data, #/s CH MB ENC CIPHER AUTH ESSID
xx:xx:xx:xx:xx:xx 0 0 79 0 0 6 54e. WPA2 CCMP PSK VMxxxxxxx
BSSID STATION PWR Rate Lost Frames Probe
It is my understanding there should be a significant amount more beacons, especially from an AP in the same room. I'm also unsure if this is the reason I'm not seeing any devices authenticate against the AP or if that is another issue entirely.
Any idea what the problem might be?
EDIT: Really oddly, if I bring both the wifi card and it's associated monitor interface down via ifconfig while running airodump-ng, the beacons start jumping up on the AP. I tested this behaviour again after restarting at get the same thing. Still don't see any client's trying to connect however.