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Minimum TX power

Dig Kleppe

According to the datasheet the minimum TX power is -20dBm

In software this can be set to -40dBm:

uint32_t sd_ble_gap_tx_power_set

(

uint8_t 

role,

Supported tx_power values: -40dBm, -20dBm, -16dBm, -12dBm, -8dBm, -4dBm, 0dBm, +3dBm and +4dBm.

In a product using the NRF52 we found this remark:

Power level 0 (=-30dBm) is not available for beacons that are using the nRF52 chips like Beacon Pro (BP16-3), Smart Beacon 3 (SB18-3), S18-3, etc. 

So what is the truth?

It is important for us to have a low range.

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  • +1

    Hi

    What is stated in the Product specification, (-20dBm) is what we have tested during production and is guaranteed to work. The registers go down to -40dBm, and it will probably work, but it is not tested, so the side effects this setting might bring are unknown. Reasons for TX power levels lower than 20dBm not being available for beacons and other modules are probably due to these side-effects. It is not very well stated in the product specs, but I do not recommend you go lower than -20dBm, even though it is possible.

    NOTE: Depending on exactly how low range you want, the NFC feature might be something worth taking a look at.

    Best regards,

    Simon

Reply
  • +1

    Hi

    What is stated in the Product specification, (-20dBm) is what we have tested during production and is guaranteed to work. The registers go down to -40dBm, and it will probably work, but it is not tested, so the side effects this setting might bring are unknown. Reasons for TX power levels lower than 20dBm not being available for beacons and other modules are probably due to these side-effects. It is not very well stated in the product specs, but I do not recommend you go lower than -20dBm, even though it is possible.

    NOTE: Depending on exactly how low range you want, the NFC feature might be something worth taking a look at.

    Best regards,

    Simon

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