Ham Radio General Class Test FREE Ham Radio General Class Test Antennas and Feed Lines Questions and Answers 2

Question 1

What is the approximate length of a quarter-wave vertical antenna for 14.2 MHz?

Accepted Answer

16.5 feet

Answer

33 feet

Answer

5.2 feet

Answer

67 feet

Question 2

What type of feed line loss increases significantly when the line is operated with high SWR?

Accepted Answer

Coaxial cable

Answer

Open-wire ladder line

Answer

Waveguide

Answer

Hardline

Question 3

What is the primary advantage of a log-periodic dipole array (LPDA) antenna?

Accepted Answer

Wide bandwidth with consistent gain and impedance

Answer

Highest possible gain on a single band

Answer

Smallest physical size for any frequency

Answer

Elimination of feed line losses

Question 4

What happens to the feed point impedance of a half-wave dipole as it is raised from near ground level to a height of one wavelength?

Accepted Answer

It fluctuates between approximately 50 and 90 ohms

Answer

It steadily increases to over 300 ohms

Answer

It remains constant at 73 ohms

Answer

It drops to near zero ohms

Question 5

Which of the following describes the velocity factor of a feed line?

Accepted Answer

The speed at which a signal travels through the line compared to the speed of light

Answer

The rate at which signal strength decreases per unit length

Answer

The maximum voltage the line can handle before breakdown

Answer

The ratio of capacitive to inductive reactance in the line

Question 6

What is the purpose of a balun at the feed point of a dipole antenna when using coaxial cable?

Accepted Answer

To convert between balanced and unbalanced systems and reduce common-mode current

Answer

To amplify the signal before it reaches the antenna

Answer

To filter out harmonic emissions

Answer

To increase the bandwidth of the antenna