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Navigation System Concepts Course 41915001


This 20-day course provides training for technicians on concepts of VOR/DME using VOR, Type FA-9996. The course is 80% Academy lecture and 20% Academy laboratory. Lecture subjects include transmitting distance and azimuth, directional couplers, Class C amplifiers, RTA-2 antenna, AM modulation, antennas and radiation patterns, limacon and audio phase concepts, and error analysis. Laboratory subjects include introduction to VOR, pulse train, monitor and control screen introduction, space modulation, and error analysis.


At the conclusion of the course, participants will be able to:
  • Recognize the function of the VOR; determine how VOR courses are developed; and predict the phases of the goniometer outputs with respect to the transmitter’s instantaneous R-F phase.
  • Identify the process of modulation; identify the various parts of the composite modulated waveforms; calculate the modulation factors; analyze the modulation process by employing R-F phasing; and identify the voltage components developed in the de-modulation process.
  • Calculate the average, peak, and effective powers and modulation, and recognize the usage of various symbols used for abbreviations of voltage, current, power, and resistance.
  • Calculate the effective and apparent space modulation, and determine the results of quadrature phasing the VOR.
  • Distinguish between carrier energy and double-sideband suppressed carrier energy, and examine the content of the inputs and outputs of the solid state modulator/goniometer.
  • Analyze the Alford Loop Antenna, and analyze the generation and effects of vertically polarized energy of the VOR antenna array.
  • Analyze the transmission lines, tie-lines, bridges, L-4 lines, and VOR antennas for the proper phase relationship; analyze the VOR radiation pattern using the rotating limacon and the audio phase concepts.
  • Perform a ground check on a VOR system, and plot, analyze and evaluate VOR error curves for Index, Spread, Duantal Error, Quadrantal Error and Octantal Error.


This course provides training for electronic technicians and engineers progressing into technical positions having responsibility for operating, maintaining, and certifying/verifying normal operation of VHF Omnidirectional Range (VOR) Equipment.

PREREQUISITES: Basic Electronics, Course 44530001 Mathematics Refresher or Course 88269001 Mathematics Refresher Bypass Exam.


  • Introduction to VOR
  • Amplitude Modulation
  • Power in an AM Wave
  • Space Modulation
  • VOR Radiation Patterns
  • Course Error Analysis and Correction
  • Azimuth Measuring
  • Frequency Conversion
  • IF Amplifiers
  • Special Receiver Circuits
  • Directional Couplers
  • Delay Lines
  • Class C Amplifiers
  • Rho-Theta Antenna System

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