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.

1 Answer 1


The majority of my issues cleared up when I passed the USB wifi adapter straight through to Kali. This leads me to suggest it's a driver issue with Ubuntu.

I'm still not picking up clients connecting to the AP but that wasn't the main question I was trying to resolve with this post.

  • Fwiw, beacon frequency is a configurable setting in some wifi routers. I am not aware of any boundaries to that value, except too low frequency will result in slow association and long delays for devices in power saving mode. That was not your issue, but might be interesting to keep in mind.
    – spectras
    Jul 9, 2021 at 14:10

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