Usage

carecul@98 over 3 years ago

Hi, is it possible to use the nRF21540 only at one end or is it mandatory to have it at all ends of the network?

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0 Karl Ylvisaker over 3 years ago

Hello,

This is indeed possible, but the feasibility of it will depend on your connection topology. Only amplifying one side will primarily work in the case that you are doing unidirectional communication (such as with BLE advertising, or LE Audio broadcasts), in which case you will increase the range of the communication by only having the FEM on one end.
However, if you will be doing bi-directional communication (such as in a common BLE connection) then you will depend on receiving packets back from the peer without the FEM, which likely would limit the range gained by having the FEM on the other side of the link. The latter does however depend on what kind of device you will be communicating with, that does not have a FEM.

Best regards,
Karl
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0 Karl Ylvisaker over 3 years ago

Hello,

This is indeed possible, but the feasibility of it will depend on your connection topology. Only amplifying one side will primarily work in the case that you are doing unidirectional communication (such as with BLE advertising, or LE Audio broadcasts), in which case you will increase the range of the communication by only having the FEM on one end.
However, if you will be doing bi-directional communication (such as in a common BLE connection) then you will depend on receiving packets back from the peer without the FEM, which likely would limit the range gained by having the FEM on the other side of the link. The latter does however depend on what kind of device you will be communicating with, that does not have a FEM.

Best regards,
Karl
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0 carecul@98 over 3 years ago in reply to Karl Ylvisaker

Noted, thanks for the support! Another question, what is the TRX pin really used for? I've seen the datasheet and the DK with nRF52840 but seems like this pin is not used on the DK.

Thanks in advance!
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0 Karl Ylvisaker over 3 years ago in reply to carecul@98

carecul@98 said:
Noted, thanks for the support!

No problem at all, I am happy to help! :)

carecul@98 said:
what is the TRX pin really used for?

The TRX pin is the RF connection to the MCU. On the EK this is routed to the TRX SMA connector, you can view it as the input to the FEM, with the antennas being the outputs

Best regards,
Karl
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0 carecul@98 over 3 years ago in reply to Karl Ylvisaker

Thanks a lot for the help! I am wonderig...since I'm no RF expert, what effect could possibly have increasing the dBm of the signal over the radial propagation of it. Like, using this range extender will lower the area coverage in terms of radius?

Regards!
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0 Karl Ylvisaker over 3 years ago in reply to carecul@98

carecul@98 said:
what effect could possibly have increasing the dBm of the signal over the radial propagation of it. Like, using this range extender will lower the area coverage in terms of radius?

I am not sure that I understand what you mean here, could you elaborate?
Generally speaking, when you use the FEM to amplify the signal strength you will get a longer range for the communication between your devices.
I am not sure what you mean when you ask if using the FEM will lower the area coverage?

Best regards,
Karl
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