First part correct, only SNR affected, Sunsdr is like measuring device. Dynamic range does not change in general depending off ATT/Preamp, it just moving in scale.
for sunsdr jtdx users:
Set Preamp on +10dB, even 1kW station near is not to much for preamp enabled input. I can not imagine when ATT should be needed.
In every band set AGC OFF and set Agc value correctly depending your local environment, strongest received station should not overload audio input in jtdx.
using 32 bit audio version of jtdx is recommended (especially when You have quiet environment), 16 bit audio also works quite OK but there Agc value setting is much more critical.
Вложение 319266

