https://greatscottgadgets.com/sdr/
https://www.analog.com/en/resources/technical-books/software-defined-radio-for-engineers.html
GAIN OPTIONS:
- LNA: is the Low Noise Amplifier, which tries it’s best to amplify only the signal.
- VGA: is the Variable Gain Amplifier, this amplifies most everything entering the radio, and shouldn’t be set very high. I believe the VGA amplifies TX as well.
- AMP: is specifically the TX power amp, though people have noticed that enabling it in RX mode can raise SNR. Yours might be broken if it’s just dumping noise everywhere, a not uncommon issue.
SNR (SIGNAL - NOISE - RATIO):
A relação sinal-ruído compara o nível de um sinal desejado (música, por exemplo) com o nível do ruído de fundo. Quanto mais alta for a relação sinal-ruído, menor é o efeito do ruído de fundo sobre a detecção ou medição do sinal.