this is a screenshot of my “current tx power” tab on my hAP Lite.
so, this shows that the AP can transmit signals at 19 dbm. but only for lower data rates.
now, this is the question. what prevents the radio to use its maximum power to transmit higher data rates? why it can’t transmit electromagnetic waves at full power, if they are modulated differently or with other MCSs?
for example, for data rate of 54mbps, it only uses 15 dbm of power. as you know, 15dbm is about 2.5 times weaker that 19dbm!
Whilst I don’t know the reasoning (and won’t pretend to). This is common across all devices. The maximum output power is always higher at lower MCS levels. You will probably find that with a higher power wireless chip (2HnD not 2nD) you will be able to transmit at the level you want to (although check the specs as MikroTik do advertise these).
thanks Steveocee
yes. as you said it is common across all devices and all vendors. it looks like a law of of physics or something! and must there be a reason.
I really appreciate if anyone could explain the reason. if the answer is strait forward and short or even technical, doesn’t matter.
I searched a a lot but couldn’t find anything related.
The higher the power output is = the higher the noise level will be and that’s why the radio can’t transmit more bits without causing lots of transmission errors.
take a look at this presentation from EU MUM 2015 by Ron Touw
https://youtu.be/pmtB3LlwquA
http://www.mikrotik.com/download/share/MUM_Prague_2015_RonTouw.pdf