When constructing a Beverage antenna, which of the following factors should be included in the design to achieve good performance at the desired frequency?

  1. Its overall length must not exceed 1/4 wavelength
  2. It must be mounted more than 1 wavelength above ground
  3. It should be configured as a four-sided loop
  4. It should be one or more wavelengths long


Which is generally true for low band (160 meter and 80 meter) receiving antennas?

  1. Atmospheric noise is so high that gain over a dipole is not important
  2. They must be erected at least 1/2 wavelength above the ground to attain good directivity
  3. Low loss coax transmission line is essential for good performance
  4. All of these choices are correct


E9H03 Was DELETED from the question pool on February 1, 2016


What is an advantage of using a shielded loop antenna for direction finding?

  1. It automatically cancels ignition noise in mobile installations
  2. It is electro statically balanced against ground, giving better nulls
  3. It eliminates tracking errors caused by strong out-of-band signals
  4. It allows stations to communicate without giving away their position


What is the main drawback of a wire-loop antenna for direction finding?

  1. It has a bidirectional pattern
  2. It is non-rotatable
  3. It receives equally well in all directions
  4. It is practical for use only on VHF bands


What is the triangulation method of direction finding?

  1. The geometric angles of sky waves from the source are used to determine its position
  2. A fixed receiving station plots three headings to the signal source
  3. Antenna headings from several different receiving locations are used to locate the signal source
  4. A fixed receiving station uses three different antennas to plot the location of the signal source


Why is it advisable to use an RF attenuator on a receiver being used for direction finding?

  1. It narrows the bandwidth of the received signal to improve signal to noise ratio
  2. It compensates for the effects of an isotropic antenna, thereby improving directivity
  3. It reduces loss of received signals caused by antenna pattern nulls, thereby increasing sensitivity
  4. It prevents receiver overload which could make it difficult to determine peaks or nulls


What is the function of a sense antenna?

  1. It modifies the pattern of a DF antenna array to provide a null in one direction
  2. It increases the sensitivity of a DF antenna array
  3. It allows DF antennas to receive signals at different vertical angles
  4. It provides diversity reception that cancels multipath signals


Which of the following describes the construction of a receiving loop antenna?

  1. A large circularly polarized antenna
  2. A small coil of wire tightly wound around a toroidal ferrite core
  3. One or more turns of wire wound in the shape of a large open coil
  4. A vertical antenna coupled to a feed line through an inductive loop of wire


How can the output voltage of a multiple turn receiving loop antenna be increased?

  1. By reducing the permeability of the loop shield
  2. By increasing the number of wire turns in the loop and reducing the area of the loop structure
  3. By winding adjacent turns in opposing directions
  4. By increasing either the number of wire turns in the loop or the area of the loop structure or both


What characteristic of a cardioid pattern antenna is useful for direction finding?

  1. A very sharp peak
  2. A very sharp single null
  3. Broad band response
  4. High-radiation angle