RSSI of PCA10112 was weaker than RSSI of PC10056

[Jeffery]

Hi Nordic team

I tried SDK Connect v1.8.0 ble_peripheral_lbs_coex sample.

It found advertising signal was very weak. The distance between PCA10112 and my phone was 1 meter. RSSI was only -86dBm.

For PCA10056, at same situation, RSSI was -45dBm.

My PCA10112 was v0.9.1 version.

What is the reason? Shall I add configurations at prj.conf file to enable FEM?

Jeffery

[Jeffery]

Hi Jared

I know radio test can work nrf21540 FEM to enhance radio signal.

But, in my thought, Nordic already defined configurations of nrf21540 FEM.

If we enable these configurations at prj.conf or kconf  at any nrf bluetooth samples and selected DK board PCA10112 (nrf21540dk_nrf52840),

after compiling and flashing to DK, FEM can work correctly and enhance radio signal. No need to modify project code.

Is it correct for what I thought?

Thanks.

Jeffery 

[Jared]

Yes, but you also need to configure the FEM in your application by setting the wanted TX power etc.

[Jeffery]

Hi Jared

Appreciate your quick reply.

I cannot fine how to set 21540 FEM configurations at SDK Connect documentation website.

Would you kindly give an example for setting to me?

Jeff

[Jeffery]

Hi Jared

As Nordic released sdk connect, why not to initially set the FEM configurations at kconf file of nrf21540dk_nrf52840 folder?  It's more convenient for us to verify FEM.

Jeff

[Jeffery]

Besides,

For radio_test, it set FEM without BLE controller.

For bluetooth samples, how to set FEM with BLE controller?

[Jared]

At this point we don't have that many BLE examples that use the FEM, but the DTM example supports it. You can try to "copy" the FEM driver that is included in that example,