HAM Practice Questions 4

Question 1

What is the significance of the 'quiet zone' surrounding the National Radio Astronomy Observatory in Green Bank, West Virginia?

Accepted Answer

Strict power and emission controls apply to protect sensitive radio telescope receivers

Answer

The National Radio Quiet Zone around Green Bank imposes power limits and emission restrictions to protect the extremely sensitive radio telescope receivers from interference.

Question 2

Which type of filter has a maximally flat response in the passband but a relatively slow roll-off outside it?

Accepted Answer

Butterworth filter

Answer

A Butterworth filter is designed for a maximally flat magnitude response in the passband, sacrificing roll-off steepness compared to Chebyshev or elliptic designs.

Question 3

What is 'reciprocal mixing' in a receiver and what causes it?

Accepted Answer

Phase noise on the local oscillator mixing with a strong off-channel signal to produce interference in the IF

Answer

Reciprocal mixing occurs when the local oscillator's phase noise sidebands mix with a strong nearby signal, creating noise that falls in the IF passband and raises the receiver noise floor.

Question 4

What emission type is used when an Extra class operator transmits RTTY on HF?

Accepted Answer

J2B

Answer

RTTY using SSB audio tones (AFSK) is designated J2B — J for single-sideband suppressed carrier, 2 for a digital sub-carrier, and B for telegraphy.

Question 5

What is the purpose of a 'loading coil' placed at the base of a short vertical antenna?

Accepted Answer

To resonate the electrically short antenna at the operating frequency by adding inductive reactance

Answer

A loading coil adds inductive reactance to cancel the capacitive reactance of an electrically short antenna, bringing it into resonance at the desired frequency.

HAM - Radio Extra Class Test Practice Test

HAM - Radio Extra Class Test Practice Test

HAM Practice Questions 4