Ham Radio General Class Test FREE Ham Radio General Class Test Antennas and Feed Lines Questions and Answers 3

Question 1

What is the effect of conductor losses in a feed line operating at UHF frequencies compared to HF frequencies?

Accepted Answer

Losses are significantly higher at UHF

Answer

Conductor and dielectric losses in feed lines increase with frequency, making UHF losses substantially greater than HF losses.

Question 2

What is the typical characteristic impedance of window line (ladder line)?

Accepted Answer

450 ohms

Answer

Window line, a type of open-wire feed line, typically has a characteristic impedance of approximately 450 ohms.

Question 3

Which antenna configuration would provide the lowest angle of radiation for DX contacts on HF?

Accepted Answer

A horizontal dipole mounted at one wavelength above ground

Answer

A horizontal antenna at approximately one wavelength height produces a low radiation angle favorable for long-distance HF communication.

Question 4

What is the approximate gain of a three-element Yagi antenna over a dipole?

Accepted Answer

6 dBd

Answer

A typical three-element Yagi provides roughly 6 dB of gain referenced to a dipole antenna.

Question 5

What is the primary purpose of a transmission line stub used in an antenna system?

Accepted Answer

To provide impedance matching or filtering at a specific frequency

Answer

A stub is a length of transmission line used to introduce a specific reactance for impedance matching or to create a notch filter.

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