[Hackrf-dev] TX and RX power and selection of amplifier gains

[Fernando]

I compile here some of the information I have gathered and set out some
questions I do not know

The FAQ explains that hack rf one have three amplifiers for reception (
RF, IF and BB) and two for transmission (RF and IF)
At RX:  RF gain may be 0 or 14dB
IF (LNA) gain may be from 0 to 40 db in 8dB steps
BB (VGA) gain may be from 0 to 62dB in 2 db steps

They suggest using RF=0, IF=16, BB=16 as start point and change IF and
BB  almost same amount up/down trying to achieve a gain so good you have
a good SNR but so low you don't have distortion
You must not use RF gain unless you are receiving a very week signal and
even so you must be sure there is no other signal out of your band of
interest with high power because if it is the case you can damage your
RF amplifier
Max RX power = -5dBm   (In theory with the RF amplifier gain set to 0 it
can accept up to +10dBm but it is not recommended)


At TX
RF gain may be 0 or 14dB
IF gain may be from 0 to 47 dB in 1dB steps
There is no BB amplifier
You cant transmit without a correctly adapted antenna (for instance
without antenna) because impedance disadaptation  may produce reflection
(without antenna 100% reflection) wich will create an overshoot and can
destroy the RF amplifier.
Max TX power depends on TX frequency
10 MHz to 2150 MHz: 5 dBm to 15 dBm, generally increasing as frequency
decreases
2150 MHz to 2750 MHz: 13 dBm to 15 dBm
2750 MHz to 4000 MHz: 0 dBm to 5 dBm, increasing as frequency decreases
4000 MHz to 6000 MHz: -10 dBm to 0 dBm, generally increasing as
frequency decrease



Taking in account all the precedent, I have two questions (indeed they
are very related)

What it the max amplification you can use for TX?
When using a osmocon sink in GNU Radio, how can we calc the power we are
using for transmision?


regards