Radio Extra Class MCQ Flashcards
7 cards from real HAM practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Radio Extra Class MCQ flashcards as text
What is the meaning of the Q-signal 'QSB' during an HF contact?
Answer: Your signals are fading
QSB means 'your signals are fading' and indicates that signal strength is varying due to propagation changes.
In a phase-locked loop (PLL) frequency synthesizer, the voltage-controlled oscillator (VCO) output is divided and compared with:
Answer: A stable reference frequency from a crystal oscillator
The PLL compares the divided VCO output against a stable crystal reference; the loop filter drives the VCO error toward zero frequency offset.
Which propagation mode allows moonbounce (EME) communication?
Answer: Earth-Moon-Earth reflection of radio waves
EME uses the Moon as a passive reflector; signals travel ~800,000 km round trip with losses exceeding 250 dB requiring high-gain antennas and sensitive receivers.
What is the function of a 'splatter filter' or speech processor in an SSB transmitter?
Answer: To limit peak audio levels and improve average power, reducing bandwidth splatter on adjacent channels
A speech processor increases average modulation power and the splatter filter prevents over-modulation peaks from spreading energy into adjacent channels.
Under FCC Part 97, which of the following is a legitimate third-party traffic restriction?
Answer: Third-party traffic is banned with countries that have no third-party agreement with the US
FCC rules prohibit third-party international traffic with countries that do not have a third-party agreement with the United States.
What is the primary advantage of using a helical antenna for satellite communications?
Answer: It produces circular polarization, reducing polarization mismatch loss with tumbling satellites
Helical antennas radiate circularly polarized waves, which match the polarization of signals from spinning satellites regardless of their orientation.
When measuring the noise figure of a receiver, a calibrated noise source is used. What does a lower noise figure indicate?
Answer: The receiver adds less internal noise and is more sensitive to weak signals
Noise figure (NF) quantifies how much a receiver degrades signal-to-noise ratio; a lower NF means the receiver introduces less noise and can detect weaker signals.