Communication with cell phone towers in a hilly country may be a bit disappointing. To reduce power consumption narrow beam antennas are used, pointed towards the areas where subscriber density is large enough. In remote areas there is little or no coverage.
Here in Croatia the coverage at sea is almost nonexistent, even on local roads there are dead spots in the shadows of hills with a high aluminum content. When leaving the bay where I live, reception is lost although the antenna is still clearly visible on the top of the hill.