my guess would be that the gain is too high on the PiAware card. did you run through the configuration here: How to Install and Configure Piaware 5.0 SD card image - Quickstart Guide ?
instructions for adjusting gain are in section 10.
incidentally, -10 in the 1090 config sets the gain to auto, which is often too much gain so the starting point is often suggested as somewhere in the middle of the range (1-49)