Max TX power for BT/BLE Beacon

[CS_SD]

Hi,

I am developing a small beacon application using the nRF 52805 device, and the intent is that it will send advertising packets at a slow rate, to indicate to a partner device that it is in proximity of the beacon. Think of it as a crude geofencing implementation.

BT hardware is not my strong suite, and I was wondering what the best way is to boost the signal of the beacon, and what the maximum amplification is that I will be able to get doing that. I am also curious on the impact of this on the power consumption of the beacon, as we intent to drive it with a coin cell battery like a CR2032 and want it to last for around a year.

In general, will it be better to have one beacon with a strong amplification of the signal, or deploying multiple beacons and create  a mesh network.

Thanks, and looking forward to suggestions/input.

[Bendik Heiskel]

Hi,

The nRF52805 have a max TX power of 4dBm. By adding a front end module(FEM), like the nRF21540, you can add 20dB gain. The max TX power with the nRF21540 will be 20dBm due to the amplifier saturating at a max of 20dBm.

But adding a FEM will increase the max power consumption significantly, so you will no be able to run it of a CR2032 battery for very long.

In this case it's probably better to use multiple beacons with a mesh network.

 

Best regards,

Bendik