MAx TX pwoer of wearable device

[klaus1234]

Hi

is it from the regulatory prespective allowed to use a range extender FEM for a wearable device?

https://www.nordicsemi.com/Products/Wireless/Range-extenders

Is it from the regulatory prespective allowed to use max power (CONFIG_BT_CTLR_TX_PWR_PLUS_8=y) on NRF 52840 for a wearable device

Thx

[ketiljo]

Max permitted power in Europe is 10 dBm. There are no restriction for wearables when the power is this low.

[klaus1234]

Hi

thanks so far?

I am building some thing like a hearing aid with BLE conenction, which is transmitting/streaming data (no audio, but some other data).  Still max power is 10 db?

If it is db, how does it come on the NRF52840 can only do +8?

[ketiljo]

Yes, max power for BLE is 10 dBm. 

The output power is measured as EIRP, ie. max power in all directions. It's not uncommon to have positive antenna gain so you'd have to backoff the power a bit. For practical reasons, 8 dBm is choosen to be max here.