RE: FEM simple GPIO configuration

Gerardo Valdovinos — Tue, 03 Feb 2026 16:32:28 GMT

Hi Elfving

Thanks for you suggestion. I updated the Nordic SDK from v3.0.2 to v3.2.1 and now the FEM is working in GPIO mode. I verified it seeing the RSSI from -80dBm to -10dBm.

RE: FEM simple GPIO configuration

Elfving — Fri, 30 Jan 2026 12:44:43 GMT

Hi,

[quote user=""]Thanks in advance and I'm sorry for asking a lot of questions.[/quote]

First of all, this is no problem at all 🙂 Just blast us with questions! That is what we are here for.

[quote user=""]Is it true that nRF54L05 doesn't support FEM?
is there a plan to add FEM support on nRF54L05 in the future?
[/quote]

I believe that is a bug/oversight in the documentation, I am not getting why it shouldn't be supported. What NCS version are you using though? Just noticed that there were some additions in 3.1.

[quote user=""]Questions 3.
Is it true that channel sounding cannot be used with a FEM?
Can you suggest an option to reach that range without using a FEM?[/quote]

True: you can not use channel sounding with a FEM, due to it being very dependant on the timing, and the FEM adding another layer that throws that timing off. But for those sorts of distances you would either way only be able to use the RTT part of channel sounding, which I guess would also be technically be possible for you to implemement yourself.

Note that 100m is rather far. A coworker of mine was able to reach 4700 meters with a FEM, but it is hard to give a clear yes/no answer to this, since it also depends on the environment, with its rf-noise and whether or not its a clear line of sight etc. 100m can be possible, but I would recommend you to try it out in the environment you have in mind.

[quote user=""]
Questions 4.
Can we use coded PHY for range and channel sounding for distance, without FEM?
Can we use coded PHY for range and Bluetooth mesh together with algorithms for distance, without FEM?[/quote]

Channel sounding excludes both FEM and coded phy.

I am a bit uncertain about what you mean in your other question here. BLE mesh requires 1M PHY (for it to follow the spec atleast), but you can let your nodes both be in a Mesh network and have a BLE connection, and let the latter use coded. Mesh can also use FEM.

Regards, and have a good week-end

Elfving