Came across this site yesterday while doing some 'research' on RV/TV antennas. Put in the address/zip code and info in broadcast TV, tower location, station info and signal strength. You can move the pointer to zero in on your location. Ought to take some of the guess work out of whigh way to point the antenna.
I use an app called "TVFool" on my smartphone and tablet. It has a nice table of distances for all the available channels, signal strengths, and so forth, and a circular chart showing visually where the strongest signals are.