Higher frequencies, such as the 2.4 and 5.8 GHz used for DJI's drone control, don't follow the earth's curvature, as do very low frequencies. The radio signal behaves much like a flashlight in that regard. The chart below shows the altitude differential one would need to consider and overcome due to the Earth's curvature.
| Distance | Curvature |
|---|
| 1 km | 0.00008 km = 0.08 meters |
| 2 km | 0.00031 km = 0.31 meters |
| 5 km | 0.00196 km = 1.96 meters |
| 10 km | 0.00785 km = 7.85 meters |
| 20 km | 0.03139 km = 31.39 meters |
| 50 km | 0.19620 km = 196.20 meters |
| 100 km | 0.78479 km = 784.79 meters |
| 200 km | 3.13897 km = 3138.97 meters |
| 500 km | 19.6101 km = 19610.09 meters |
| 1000 km | 78.3196 km = 78319.62 meters |
