Why is nRF52840's RADIO TX POWER max 8dbm ?

[keunsik]

Dear

I know it is ridiculous question. Do not blame , please.

I have to explain  anyone to non-engineer.

Nation's Wireless rule  is 10dbm . by the way , RF IC  is 8 dbm.

Why? 

He asked. I explained It is made by chip designer  after many considerations.

But, it is not accepted.

I was frustrated.

But, Requesting Answer, i must answer.

Answer, please.

[ketiljo]

10 dBm is the maxium limit in many areas, yes. This is radiates measurements where you measure the maximum radiated power in all directions. For an omnidirectional antenna, the power will be equal in all direction. But there are no antennas that behaves like. It not unusual to have some gain in one direction so you have to back off the output power a bit to pass the 10 dBm limit.

In terms of range, the difference between 8 dBm and 10 dBm isn't that great. You must increase the output power by 6 dB to double the range. 

8 dBm was chosen as a good compromise between current draw and output power.