Your receiver typically has a decibel meter. Mine have, and you can get this typically by doing a channel scan. It will tell you how strong each station is by bars or numbers.
I discovered this while having problems a few years back with signal from a fairly strong transmitter (only) several miles away, that was still pixelating (as viewed): The "meter" showed low signal. I queried the TV's manufacturer and they clarified that the meter indicates signal quality, of which strength is only one factor.