Trying some different settings I tweaked the gain on my Pi, if I issue the following;
sudo piaware-config -show rtlsdr-gain
it results as 25.4 - which is what I set it to.
The top line of HTOP though shows /usr/bin/dump1090-fa –gain -10
I’m guessing the piaware-config is just reading a config file somewhere and this may not have been used by piaware.
It seems dump1090-fa reads settings from /etc/default/dump1090-fa file, altered the gain setting in this file and all works fine.
My set up is Raspian Stretch with PiAware installed using apt-get install