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 these choices are correct


What is Receiving Directivity Factor (RDF)?

  1. Forward gain compared to the gain in the reverse direction
  2. Relative directivity compared to isotropic
  3. Relative directivity compared to a dipole
  4. Forward gain compared to average gain over the entire hemisphere


What is an advantage of placing a grounded electrostatic shield around a small loop direction-finding antenna?

  1. It adds capacitive loading, increasing the bandwidth of the antenna
  2. It eliminates unbalanced capacitive coupling to the surroundings, improving the nulls
  3. It eliminates tracking errors caused by strong out-of-band signals
  4. It increases signal strength by providing a better match to the feed line


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

  1. It has a bidirectional pattern
  2. It has no clearly defined null
  3. It is practical for use only on VHF and higher bands
  4. All these choices are correct


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 RF attenuation used when direction-finding?

  1. To narrow the receiver bandwidth
  2. To compensate for isotropic directivity and the antenna effect of feed lines
  3. To increase receiver sensitivity
  4. To prevent receiver overload which reduces pattern 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


What is a Pennant antenna?

  1. A four-element, high-gain vertical array invented by George Pennant
  2. A small, vertically oriented receiving antenna consisting of a triangular loop terminated in approximately 900 ohms
  3. A form of rhombic antenna terminated in a variable capacitor to provide frequency diversity
  4. A stealth antenna built to look like a flagpole


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 utilizing high impedance wire for the coupling loop
  3. By winding adjacent turns in opposing directions
  4. By increasing the number of turns and/or the area


What feature of a cardioid pattern antenna makes it useful for direction finding?

  1. A very sharp peak
  2. A very sharp single null
  3. Broadband response
  4. High radiation angle