Revision history [back]

Since that adapter is bgn only (no 5GHz), I suspect the issue for you is band:

1. Most dual band clients prefer 5GHz, if available
2. The AP is stated as set for 802.11abgn, so is dual band

I would suspect your clients are on 5GHz but you can only capture on 2.4GHz so are missing most of the traffic. If you can't change the AP, you can try to force a client to prefer 2.4GHz, or buy a capture adapter that supports dual band.