We have a Zyxel Wifi with an NXC2500 and two WAC6503D-S access points in our office. Around 30 devices are connected. We have both a 2,4GHz and a 5GHz radio active, both on channels without known interference.
We often experience bad Wifi performance, which means less than 1MBit/s for some minutes, while the shown link speed is > 800MBit/s. Stations connected by cable don't have any problems.
It is a sporadic problem, therefore hard to debug. We already checked the signal strength of the stations, which is fine. We tried diffent channels without any impovement.
To trace the problem, I setup two other access points (both Netgear, different models) on free channels and connected them directly to our modem. Interestingly, also there the performance is not satisfying. On the 2,4GHz band (CH1), the throughput is only around 2MBit/s. On 5GHz it's 80MBit/s (which is fine) most of the time, but sometimes drops to 30MBit/s too, even if there shouldn't be any other device sending on this channel and the access point is located only 1m away.
I would be interested to know how I can get further here. Are there any devices which can detect interferences? Or programs which show if there are problems with the connection (like dropped packets etc)? Any other ideas?
Thanks for any help, I'm slowly out of ideas.