DVOR Advantage RNAV
The principle advantage of DVORDVOR —Doppler VHFVHF —Very High Frequency Omnidirectional RangeDVOR —Doppler VHFVHF —Very High Frequency Omnidirectional Range over CVORCVOR —Conventional VHFVHF —Very High Frequency Omnidirectional RangeCVOR —Conventional VHFVHF —Very High Frequency Omnidirectional Range is a reduction in siting error, the error caused by, for example, trees and other obstructions near to the site of the beacon. The DVORDVOR —Doppler VHFVHF —Very High Frequency Omnidirectional RangeDVOR —Doppler VHFVHF —Very High Frequency Omnidirectional Range does this by changing the type of modulation used for the reference and variphase signals.
For a CVORCVOR —Conventional VHFVHF —Very High Frequency Omnidirectional Range, the reference is frequency modulated and the variphase amplitude modulated. For a DVORDVOR —Doppler VHFVHF —Very High Frequency Omnidirectional Range these are the opposite way around. Remembering CFA DAF (CVORCVOR —Conventional VHFVHF —Very High Frequency Omnidirectional Range Frequency/Amplitude, DVORDVOR —Doppler VHFVHF —Very High Frequency Omnidirectional RangeDVOR —Doppler VHFVHF —Very High Frequency Omnidirectional Range Amplitude/Frequency) is a simple way to remember this for the exam.