HAM FREE Ham Radio Extra Class MCQ Questions and Answers 2 — Questions and Answers
Question 1: What is the purpose of a Smith chart in amateur radio?
- To display complex impedance and admittance on a single graph (Correct answer)
- To calculate antenna gain in dBi
- To measure SWR at multiple frequencies simultaneously
- To plot signal propagation paths over terrain
Correct answer: To display complex impedance and admittance on a single graph
A Smith chart graphically represents complex impedance and admittance, making it easier to design matching networks and analyze transmission line behavior.
Question 2: Which emission type designator indicates a single-sideband suppressed-carrier voice signal?
- F3E
- A1A
- J3E (Correct answer)
- C3F
Correct answer: J3E
J3E designates a single-sideband suppressed-carrier analog voice emission in the ITU emission designator system.
Question 3: What is the maximum symbol rate permitted for RTTY or data emission on the 20-meter band?
- 300 baud (Correct answer)
- 1200 baud
- 9600 baud
- 56 kilobaud
Correct answer: 300 baud
FCC Part 97 limits the symbol rate for RTTY and data emissions on the 20-meter band to 300 baud for Extra class licensees.
Question 4: What is the typical noise figure of a well-designed preamplifier for weak-signal VHF work?
- Less than 1 dB (Correct answer)
- About 6 dB
- About 10 dB
- Greater than 15 dB
Correct answer: Less than 1 dB
A high-quality VHF preamplifier for weak-signal work typically achieves a noise figure below 1 dB to maximize receiver sensitivity.
Question 5: In a superheterodyne receiver, what causes an image frequency response?
- Oscillator phase noise mixing with adjacent signals
- A signal at twice the IF frequency away from the desired signal mixing to the same IF (Correct answer)
- Intermodulation distortion in the RF amplifier stage
- Harmonic radiation from the local oscillator
Correct answer: A signal at twice the IF frequency away from the desired signal mixing to the same IF
An image frequency is separated from the desired signal by twice the IF, and it mixes with the local oscillator to produce the same IF output.
Question 6: What is the function of a directional coupler in a transmitter system?
- To combine signals from multiple transmitters onto one antenna
- To sample forward and reflected power without interrupting the transmission line (Correct answer)
- To filter harmonic emissions before they reach the antenna
- To switch between multiple antennas automatically
Correct answer: To sample forward and reflected power without interrupting the transmission line
A directional coupler samples a small portion of forward and reflected power on a transmission line for measurement purposes without significantly affecting the main signal.
HAM FREE Ham Radio Extra Class MCQ Questions and Answers 2
What is the purpose of a Smith chart in amateur radio?