RSSI Instability: Seeking Insights on nrf52840

RE: RSSI Instability: Seeking Insights on nrf52840

ohad — Mon, 04 Dec 2023 13:54:06 GMT

FEM is not enabled.

I get the same results (for the same exact rssi values) when bypass the LNA.
Currently, to debug this, I've set the LNA to bypass mode.

RE: RSSI Instability: Seeking Insights on nrf52840

ketiljo — Mon, 04 Dec 2023 13:22:49 GMT

Are the measuremenst done with the LNA in the FEM enabled? If so, either set it in bypass mode or do the measuremenst with a DK or another board without any extra on the antenna interface.

RE: RSSI Instability: Seeking Insights on nrf52840

ohad — Wed, 29 Nov 2023 13:20:48 GMT

I see the same patterns (for exact same RSSI levels) connected by cable. i.e: transmitter->cable>attenuator>reviever

RE: RSSI Instability: Seeking Insights on nrf52840

ketiljo — Wed, 29 Nov 2023 10:15:24 GMT

Are these measurements done radiated, i.e with the antenna in the equation? If so, you need to rule out varations due to reflections and fading and do the measurements in a conducted setting instead.

In real life applications, you will see at least 10 dB difference in the RSSI values due to fading effects. So if you're trying to use the RSSI value as more than an indication and very course range estimation, you're out of luck.