45 m (150 ft) from antenna to FlightAware Pro Stick Plus

Compared to what?

That not quit accurate. The “claimed” gain of your RCA amp is 13-18dB (950-2150MHz)
while your first amp made no claims at all
and your third amp claimed 20dB (950-2150MHz). That’s about 5dB up on the RCA amp

You could start a religion with that, but not much good evaluating amps.

A typical sat amp