FCC Technician Exam Question Of The Day (T8C01)

Q) Which of the following methods is used to locate sources of noise interference or jamming?

A) Radio direction finding

 NJ2X Notes:
Radio direction finding involves using antennas and receivers to determine the location of an RF source.  The are many different techniques:
  • Directional antennas - Using highly directional antennas such as yagi's, loops, etc. you can determine the direction of the signal.
  • Pseudo-doppler  - antennas are arranged in a circular array and then sequentially sampled to simulate the effect of a rotating antenna.  This modulates the received signal and the phase of this modulation can be used to determine the direction of the signal.
  • Phase interferometer - the phase difference between two spacially separated antennas is used to determine the direction of the signal.
Using triangulation in conjunction with the above techniques can help pinpoint a transmitter's location.