What is required for accurate VOR operation?

For accurate VOR (VHF Omnidirectional Range) operation, it is essential to have a direct line of sight to the VOR station. This requirement stems from the nature of VOR systems, which rely on radio signals transmitted by ground-based stations. The VOR receiver in an aircraft determines its position by measuring the phase difference of these signals. If there are obstacles such as mountains or buildings blocking the signals, the accuracy of the position information provided by the VOR can be compromised. Therefore, clear visibility to the VOR station ensures that the signals can be received without interference, allowing for reliable navigation and course monitoring.