Range Extender nrf21540 with nrf52833 custom board

RE: Range Extender nrf21540 with nrf52833 custom board

Sagar Bhosle — Thu, 06 Nov 2025 11:42:58 GMT

okay , I forgot to tell you

We done half testing now i get range upto 300 meters and the testing is still going thank you for your support kenneth

RE: Range Extender nrf21540 with nrf52833 custom board

Kenneth — Fri, 22 Aug 2025 16:54:28 GMT

Please be aware that RSSI is extremely unreliable measure. It depends on very many factors that you don't have any control over. Please get yourself access to a spectrum analyzer if you want to do some measurements.

Kenneth

RE: Range Extender nrf21540 with nrf52833 custom board

Sagar Bhosle — Fri, 22 Aug 2025 05:32:58 GMT

yes Kenneth but you see the pdf which i uploaded, in this you can see the difference of RSSI value after increasing gain

RE: Range Extender nrf21540 with nrf52833 custom board

Kenneth — Thu, 21 Aug 2025 14:39:24 GMT

The only way to change the output power is to set CONFIG_BT_CTLR_TX_PWR_ANTENNA="the output power you want".

The software will then use the CONFIG_MPSL_FEM_NRF21540_TX_GAIN_DB to adjust the output power from the nRF52833 to get as close as possible to CONFIG_BT_CTLR_TX_PWR_ANTENNA it can.

Kenneth

RE: Range Extender nrf21540 with nrf52833 custom board

Sagar Bhosle — Thu, 21 Aug 2025 07:24:25 GMT

devzone.nordicsemi.com/.../7651.nRF21540_5F00_TX_5F00_gain_5F00_Testing-_2D00_-18-AUG-25.pdf I upload it Can you review it Kenneth.

RE: Range Extender nrf21540 with nrf52833 custom board

Kenneth — Tue, 19 Aug 2025 10:06:21 GMT

You need to upload the files here.

Kenneth

RE: Range Extender nrf21540 with nrf52833 custom board

Sagar Bhosle — Tue, 19 Aug 2025 07:32:41 GMT

Hello Kenneth, this is my test report. I tested it indoors in my office. After changing the gain at different distances, I got these readings. Can you take a look at my testing report and suggest what is wrong, and whether the gain increased as compared to the expected output? https://docs.google.com/spreadsheets/d/1mRTk7Rl9Xn_e40sqsnp3fgII25EL8vDn/edit?gid=247305807#gid=247305807

RE: Range Extender nrf21540 with nrf52833 custom board

Kenneth — Thu, 07 Aug 2025 13:44:54 GMT

If you have access to a spectrum analyzer and/or current consumption measurement, then you can get some indication that output power increases as you change CONFIG_BT_CTLR_TX_PWR_ANTENNA to what output power you want. Note that both sides of the link need increased output power, else you may be limited with the one peer with lowest output power.

Kenneth

RE: Range Extender nrf21540 with nrf52833 custom board

Sagar Bhosle — Thu, 07 Aug 2025 11:52:59 GMT

Hello kenneth , i am not using nrf21540 ek module , actually iam using custom board which have inbuilt nrf52833 and nrf21540 ic , and i create a custom board and select the board in add build confg and because of im not using nrf21540 ek module im not selecting dkshield in build confg

can you suggest me how i can verify my range extender tx is set and it works , i test LOS (line of sight) testing but it did not work

RE: Range Extender nrf21540 with nrf52833 custom board

Kenneth — Thu, 07 Aug 2025 11:13:55 GMT

Hi,

I believe you will the following thread clarifying:
Using nrf5340dk with the nrf21540 EK

I suspect what you are missing is: CONFIG_BT_CTLR_TX_PWR_ANTENNA=20

Kenneth