VOR

VOR (VHF Omnirange Navigation System) #

General #

  • Between 108.10 and 117.95 Mhz
  • Reference phase: 360degree signal that goes out 30 times a second
  • Variable phase: Rotates at a rate of 30 times per second
  • Phase difference: Principle is the difference between the two in direction
  • Radials: The “bearing” radiated from the VOR station

Tips #

  • VOR does NOT care about your heading. It’s just “telling you” where you are and you are telling IT where you want to go.
  • Radials are broadcasted OUT / away from the station
  • To go TO the station, you must go THROUGH the station
  • Add or subtract 180 to figure out the correct radial for to/from
  • Imagine the little “circle” in the middle of the CDI to be your airplane and the “LINE” to be the radial from the station.
  • When it shows “checkered” or BOTH TO and FROM or OFF that means you are perfectly 90 degrees from VOR
  • CDI (Course Deviation Indicator): Verticle needle that shows left or right of the course
  • When tuned to an ILS localizer, the vertical needle indicates deviation from selected localizer course. The horizontal needle shows above or below the glide path
  • GS (Glide Scope): Indicates it’s using the glide scope
  • If you see red NAV / VAR, barber pole or OFF instead of TO/FR indicator then it’s unreliable.
  • OBS (knob) is the Omni Bearing Selector.

Usage #

Left / Right off course #

  • The “line” shows where you are off course in relation to the little circle in the middle.
  • So this means you are either left or right of the radial from / to the station.

Getting your bearing #

  1. Get the freq from the map

Shows on the map in the small box on Canada charts with the morse code + name of the VOR.

  1. Turn the OBS (Omni Bearing selector) until the CDI needle is centered and you have FROM.

If you want TO then you flip it 180 degrees until it says TO designator. It will be exactly 180 from the current radial.

Intercepting a course #

  1. Get the desired radial by checking a VFR or IFR chart.

  1. Intercept the course, turn 30 degrees in the direction of the CDI to intercept the course. 30 degrees is the most common and easy to use

  2. Track the radial

  1. Adjust for wind, if you find yourself blown off the radial, note the amount of deflection, then intercept the radial by turning the aircraft towards the radial twice as many degrees as the deflection. When the needle centers, turn only halfway back to the original heading to provide wind correction angle.

Triangulation #

  1. VOR 1: Turn the OBS nob until the CDI is centered and you have a FROM flag
  2. VOR 2: Same as above
  3. Use the chart to determine where you are.

Testing #

Testing / VOR checks.

When tuned to a test freq (usually at main airports):

  • Freq located in airport supplement usually
  • 000 should show FROM
  • 180 should show TO

Example #

With bearing set to 0degrees, the following would be:

  • A, B, H will show TO
  • D, E, F will show from
  • C and G will show OFF