Airmon-ng/Airodump-ng – Low Beacon Count on certain networks

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 5 minutes

 CH  6 ][ Elapsed: 5 mins ][ 2020-06-13 16:53 ][ fixed channel mon0: -1                                            BSSID              PWR RXQ  Beacons    #Data, #/s  CH  MB   ENC  CIPHER AUTH ESSID   xx:xx:xx:xx:xx:xx    0   0        6        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.

Any idea what the problem might be?