Are you talking about the so-called "refraction"?
Discussion
Yes. And I assume I know what I talk about because I used to work in R&S's radio monitoring and location department.
None of the devices we developed there would work if the earth wasn't the size and shape claimed in the textbooks and if refraction didn't work exactly as physics describes.
Interesting. I always wondered why optical refraction was never proven experimentally to work horizontally. If it is able to pull objects up from under the horizon vertically by many kilometres, it should be able to let the observer see behind the corner of a wall horizontally under proper conditions.
I also don’t see why the radio stuff fundamentally wouldn’t work on other possible sizes and shapes of the earth. Have you heard of the LORAN-C system?