Contents
How is the variable frequency of VOR modulated?
The variable phase signal is directly amplitude modulated on the VOR carrier. The amplitude modulation of the variable phase signal is generated by a special antenna array which produces a rotating cardioid shaped antenna pattern rotating at a 30 Hz rate.
What is VOR modulation?
The VOR signal is a composite signal consisting of a reference signal that is frequency modulated on to the VOR sub-carrier frequency and a variable phase component which provides bearing information. The variable phase signal is amplitude modulated at a rate of 30 Hz onto the primary VOR carrier frequency.
What is difference between VOR and DVOR?
There are two types of VOR aids: CVOR (Conventional VOR) and DVOR (Doppler VOR). DVOR is the further development of the CVOR, providing improved signal quality and accuracy compared to CVOR at demanding locations, where the geographical conditions are difficult, using the Doppler effect.
What are VOR used for?
Overview of VOR VORs provide azimuth information (the heading of the aircraft) and are generally used during the en‑route phase of flight or on non-precision approaches to a runway. VOR stations are used all over the world.
How far does a VOR signal reach?
VOR stations are fairly short range: the signals are line-of-sight between transmitter and receiver and are useful for up to 200 miles. Each station broadcasts a VHF radio composite signal including the navigation signal, station’s identifier and voice, if so equipped.
Is VOR still used?
In its more basic form, a VOR facility can be used to go directly to an airport. As of 2018, pilots still use VORs as a primary navigational aid, but as more and more aircraft are equipped with GPS receivers, VORs most likely will be retired from use.
What is the principle of VOR?
The frequency range for a VOR is between 108.0 MHz and 117.95 MHz. Every VOR is oriented to magnetic north (more on this in a bit), and emits 360 radials from the station. The VOR sends out one stationary master signal, and one rotating variable signal. These are also called “reference” and “variable” phases.
How do you tell if a VOR is high or low?
As far as high/low VOR, one way to tell is to look at the High/Low enroute IFR charts. You can see two VOR stations on here labeled Minot Intl and Devils Lake Rgnl with a victor airway between them (V430).
Do airplanes still use VOR?
Where does the 30 Hz reference signal come from?
The conventional 30 Hz reference signal is on a 9960 Hz frequency modulated (FM) subcarrier. The variable amplitude modulated (AM) signal is conventionally derived from the lighthouse-like rotation of a directional antenna array 30 times per second.
How many sine signals does a VOR receiver receive?
A VOR receiver, regardless of the technology behind, receives two sine signals repeating 30 times per second: Reference and variable signals, and determines the bearing by solely measuring the difference between their phases.
Which is the 30 Hz reference tone in VOR?
Note for a conventional VOR, the 30 Hz reference tone modulates the 9,960 Hz subcarrier in F3 (to create the sidebands) instead of the carrier itself in A3. The modulation depth is 30%.
What are the different types of Vor antennas?
There are several types of conventional VORs using either rotating or static antennas. What they have in common is: They are relatively compact. Bearing is determined from a HF signal rotating 30 rounds per second.