Orientation of device during channel sounding

[Triscuit]

Hi, I was curious if the orientation of the devices matter for channel sounding using NRF54l15. I have noticed that channel sounding works best when the initiator and reflector are facing each other, when I turned one of them around, the readings stopped coming in. By placing them back to back I was consistently getting weak connections and no readings. I was under the impression that the NRF54l15 sends out omnidirectional signals, which would be the same in all directions, but my tests showed otherwise.

Sincerely,

Triscuit

[Asbjørn]

Hello Triscuit,

ideally the antenna should be omnidirectional, but in practice there isn't such a thing. All antenna will have variations in the radiation pattern from the layout of the board, ground plane, components around the antenna and so on. Often the forward direction is more into open air as well just because that's the intended direction for the application to be oriented in.

So I'd expect you to see difference at the same range with different orientations between the two antennas. By difference it could be a bit, but weak connections or no readings sound unlikely unless there's something blocking the signal in that direction. 

Q1: Are you testing this with the nRF54L15 DK or is a custom board?

Q2: If custom board, are you able to share some details on what it looks like, antenna you've used and so on?

Q3: What is the range between them (back to back) when you start losing the readings?

Q4: How much weaker signal are you reading? 

Best regards

Asbjørn

[Triscuit]

Hi Asbjorn,

Thank you for the reply. I am testing with a custom board. I am not sure how to describe it since I am responsible for only the software. The antenna seems to be shorter than the dk one if that helps. The range I am losing connection it around 15-20m. The signal was weak enough for me to not receive valid channel sounding readings. However, I have also tested with the dk's, even though the signal was much stronger overall, I noticed the difference in orientation as well. Thank you.

Sincerely,

Triscuit

[Asbjørn]

Hi Triscuit,

Maybe the antenna is too short, but can't really say without more details. It sounds like you were reassured a bit, but let us know if there are any more we can do to assist you.

Best regards

Asbjørn