I’m kind of struggling with understanding the VOR in the airplane as well as on the ground. My instructor wants me to be able to explain exactly and in detail to him how it works, and I’ve been doing reading and studying, but could anyone help me?
I feel like I should know this and I feel dumb for having to ask but I’m really trying to get a very thorough understanding of it
VORs send out a radio signal encoded with azimuth from the station in all directions (360 degrees), so this is where your radials come from. It actually does this by rotating the direction that it’s emitting the signal (which is why some older VORs have a visibly spinning unit).
The VOR receiver in your airplane is really just a radio receiver with some extra equipment to decode the encoded information being broadcasted by the station. Your receiver is tuned to the VOR’s frequency, and the decoded information is relayed to your instruments (OBS/HSI). The course selected on your OBS/HSI just changes which radial you’re waiting to receive from the station, and that’s how you get your course information.
Since VORs operate on a radio frequency, most can transmit voice and sound, so the same frequency transmits the station’s identifier and some transmit weather advisories (HIWAS).
Also important to know the service volumes of the different types of VORs (Terminal, Low, High). The AIM puts it in a nice little table but I’ll try my best to keep it easy to read:
Terminal - 1000’ to 12,000’ AGL and 25NM radius
Low - 1000’ to 18,000’ AGL and 40NM radius
High (this one has 3 layers) - 1000’ to 14,500’ AGL, 40NM radius. From 14,500’ to 60,000’ AGL, radius of 100NM. And from 18,000’ to 45,000’ AGL, radius of 130NM. Think of it kind of like the whole upside down wedding cake thing, except the widest portion is in the middle.
Hope this helps, and let me know if you need any more!