Hi,
I am testing the radio_test (short-range) sample on an nRF54LM20A DK. The test setup is:
-
Board: nRF54LM20A DK
-
Sample:
peripheral/radio_test(NCS version: <v1.0.0>) [Radio test] -
Mode: Bluetooth LE 1M (
data_rate ble_1Mbit) -
Channel: 2400 MHz (
start_channel 0) [BLE radio test] -
TX power: -40 dBm and -46 dBm (very low output power; nRF54L series supports down to about -46 dBm) [54L radio]
Test procedure:
-
Configure BLE 1M, channel 0 (2400 MHz), very low TX power (-40 dBm or -46 dBm).
-
Start a continuous unmodulated carrier:
start_tx_carrier -
Stop the carrier:
cancel -
Switch to RX mode:
start_rx
Observed behavior:
-
After I stop TX and enter RX mode, I still see a continuous wave around -50 dBm on a spectrum analyzer, as if something is still transmitting.
-
This only happens when TX power is -40 dBm or -46 dBm.
-
When TX power is higher than -40 dBm, the problem does not appear: after
canceland switching to RX, no residual CW is visible.
Questions:
-
Is this a known issue or limitation of the radio_test sample or the nRF54LM20A radio at very low TX power levels?
-
Could there be any special handling required when using -40 dBm / -46 dBm TX power in radio_test (for example, additional commands or delays after
cancelbefore entering RX)? -
Do you have any recommendations on how to further debug this (for example, checking specific registers or using another test mode)?
If needed, I can provide:
-
Exact NCS version and
prj.confused -
CLI command log from the UART shell
-
Screenshots from the spectrum analyzer showing the residual CW
Thanks in advance for your support!
