CSI amplitude issue when connecting 3 antennas

[bkorany]

Hello everyone,

I am working on some experiments using the CSI amplitude on the Intel 5300 card. The measurements are fine when I connect antennas 1 and 2 on the intel card. However, whenever I connect the 3rd antenna (the 3rd port), I notice a lot of spikes/burst noises in the CSI amplitude time series on that port as well as port 2. This issue has been consistent with me for a while now. I am not sure what the reason might be. It might be because of some "crosstalk" between the ports, especially that the 3rd port lies in between ports 1 and 2, but I am not sure.

I was wondering if anyone has experienced such behavior before, and if so, how did you overcome it?

Thanks.

[lagharimanzar]

Hi

I am also facing same issue. Yes this crosstalk is from other two ports at wifi card.
In my setup I am using Intel NUC where WiFi card is installed and I am using IPX to RP-SMA cables from card to outside for antennas connections.
In order to be sure about working condition of each antenna port at 2.5GHz as well as 5GHz, I have used cable connection instead of over the air between transmitter and receivers each one by one for all antenna ports outside and I have completely sealed the input ports of other two antennas while extracting CSI from one but still i can see spikes received by other two antennas ports.
In the end I came up with thoughts that due to not having proper coverup/shielding of the ports at the WiFi card I am receiving the spikes.

My question: How strong (in dB) are those spikes?