Ham Radio Technician Test Antennas & Feedlines 4

Question 1

What is the effect of operating an antenna significantly off its resonant frequency without a tuner?

Accepted Answer

High SWR and increased feedline loss

Answer

Operating an antenna off-resonance causes a high SWR, which increases feedline losses and can stress the transmitter's output stage.

Question 2

For a vertical antenna mounted on a vehicle rooftop, the car body serves as:

Accepted Answer

The ground plane

Answer

The metal vehicle body acts as the ground plane, providing the RF return path for the vertical antenna.

Question 3

What does antenna 'gain' mean in practical terms?

Accepted Answer

Concentrating radiated power in a preferred direction compared to a reference antenna

Answer

Antenna gain is a measure of directivity — it focuses power in certain directions at the expense of others, not creating new power.

Question 4

Which connector type is commonly used with RG-8 or RG-213 coax for HF amateur radio?

Accepted Answer

PL-259 (UHF connector)

Answer

The PL-259 (sometimes called a UHF connector despite its name) is standard for HF amateur radio applications with large-diameter coax.

Question 5

What is a J-pole antenna?

Accepted Answer

A half-wave radiator fed at the base via a quarter-wave matching stub

Answer

The J-pole uses a quarter-wave matching section (the 'J' foot) to feed a half-wave vertical element at its natural current maximum.

Ham Radio Technician Test Practice Test