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

Question 1

An amateur operator is installing a new HF station and wants to feed a center-fed dipole antenna with 50-ohm coaxial cable. What is the primary function of a balun in this setup?

Accepted Answer

To convert the balanced antenna feedpoint to the unbalanced coaxial cable

Answer

To filter out-of-band signals

Answer

To increase the antenna's gain

Answer

To provide a DC path to ground for static discharge

Question 2

A ham is using an SWR meter to check a newly installed antenna system. The reading at the low end of the 20-meter band is 2.5:1, and at the high end, it is 1.5:1. What does this indicate about the antenna's length?

Accepted Answer

The antenna is too short for the band.

Answer

The antenna is too long for the band.

Answer

The antenna is perfectly resonant.

Answer

The SWR meter is likely defective.

Question 3

Which of the following feed lines generally has the lowest loss per unit of length at HF frequencies, especially when dealing with a high SWR?

Accepted Answer

450-ohm ladder line

Answer

RG-58 coaxial cable

Answer

RG-213 coaxial cable

Answer

75-ohm hardline

Question 4

A General Class operator wants to build a half-wave dipole antenna for the 40-meter band, centered on 7.150 MHz. Using the standard formula, what is the approximate total length of the antenna in feet?

Accepted Answer

65.5 feet

Answer

32.7 feet

Answer

139.8 feet

Answer

131 feet

Question 5

What is the primary advantage of a 3-element Yagi antenna compared to a simple dipole antenna for the same frequency?

Accepted Answer

It provides forward gain and directivity.

Answer

It is omnidirectional.

Answer

It has a higher takeoff angle.

Answer

It is less affected by height above ground.

Question 6

An operator measures a high SWR of 3.5:1 at the transmitter. What is a potential consequence of operating the transmitter under this condition for an extended period?

Accepted Answer

The transmitter's final amplifier stage could be damaged.

Answer

Improved signal-to-noise ratio on receive.

Answer

The antenna's polarization will automatically switch.

Answer

The feed line loss will decrease significantly.

An amateur operator is installing a new HF station and wants to feed a center-fed dipole antenna with 50-ohm coaxial cable.What is the primary function of a balun in this setup?

An amateur operator is installing a new HF station and wants to feed a center-fed dipole antenna with 50-ohm coaxial cable.
What is the primary function of a balun in this setup?