I don't even attempt to figure out physics or logic.
For example, Lake Lure NC. I can walk out on the deck, look to my left, and there's Bearwallow Mountain with all its repeaters. I literally have line of sight. Can't hit them even with a 50watt mobile and a 6' antenna.
However, I can hit a repeater on the other side of the mountain with a 10watt HT with Nagoya 771 antenna.
Maybe I need to cut back on the bourbon. LOL