Link quality issues, please help me understand

Hi everybody,

I am quite new to this zigbee stuff, so maybe there are things I simply overlooked and didn’t quite understand.

I have the following setup:

1 x Raspb.Pi4 with CC2531 Coordinator, based on the ground floor, with external antenna, but signal seems quite weak. ( Firmware CC2531ZNP-Prod .hex (19.06.2019))
on the same ground floor, there are multiple sensors and switches, all connected through the IKEA light bulb, and the signal is good and reliable. I have the feeling that the signal of the IKEA bulb is a couple of times stronger than the CC2531.

On the upper floor, things get interesting:

  • One motion sensor, although it’s located next to a Philips Hue bulb, it’s connected to the downstairs IKEA bulb - No issues here, signal is good and reliable nevertheless

  • One Philips Hue bulb, connected to both coordinator and IKEA bulb - connections seems reliable.

  • The big problem is with the Osram smart plug, which is connected to all other routers (good signal) and the coordinator (very poor signal). In Home Assistant, the displayed signal quality is always 0, and most of the times I get MAC no ack and the plug is not responding to commands. Moving the coordinator antenna a few centimetres to one side sometimes helps and the issued commands are getting through, but very unreliable.

Now, for the questions:

  • Shouldn’t this plug talk to the coordinator through the other routers, if the signal on those legs is better ?
  • Why is it still using the almost 0 signal quality link with the coordinator when there are better routes ?
  • What would be the solution ? Adding an extra router seems contra-productive, as there are already routers in the vicinity of the plug or with good lqi to the plug.
  • a better coordinator ? should I replace it with a CC2530 + CC2591 ?

Thank you in advance.

Try re-pairing the Osram plug where it is located now. This might help.