Total posts : 45366
The discussion is right on target and I think I can contribute another piece of the puzzle to help get a big picture of what is happening.
Is “the edge of the property” uphill from the transmitter?
I have found in my experience that AM signals do not want to go uphill from the antenna, and I have done a lot of experimenting with this problem, because my location is literally in a bowl, since every direction is uphill from here.
I think the AM radio industry knows this, because their towers are always on level ground or on high ground, not down in valleys or depressions.
Grounding really helps. By running radials extending in length as close to 1/4 wavelength as your property allows, the “throw” of the signal improves dramatically.
And, as was said, getting the antenna system in resonance does the rest.