Practice Questions 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 Practice Questions flashcards as text
What is the significance of the 'quiet zone' surrounding the National Radio Astronomy Observatory in Green Bank, West Virginia?
Answer: Strict power and emission controls apply to protect sensitive radio telescope receivers
The National Radio Quiet Zone around Green Bank imposes power limits and emission restrictions to protect the extremely sensitive radio telescope receivers from interference.
Which type of filter has a maximally flat response in the passband but a relatively slow roll-off outside it?
Answer: Butterworth filter
A Butterworth filter is designed for a maximally flat magnitude response in the passband, sacrificing roll-off steepness compared to Chebyshev or elliptic designs.
What is 'reciprocal mixing' in a receiver and what causes it?
Answer: Phase noise on the local oscillator mixing with a strong off-channel signal to produce interference in the IF
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.
What emission type is used when an Extra class operator transmits RTTY on HF?
Answer: J2B
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.
What is the purpose of a 'loading coil' placed at the base of a short vertical antenna?
Answer: To resonate the electrically short antenna at the operating frequency by adding inductive reactance
A loading coil adds inductive reactance to cancel the capacitive reactance of an electrically short antenna, bringing it into resonance at the desired frequency.
According to FCC rules, under what condition may an amateur station transmit music?
Answer: Only when incidental to an authorized retransmission of space shuttle communications
FCC Part 97.113 prohibits music transmission except when it is incidental to an authorized retransmission of NASA manned spacecraft communications.
What is the velocity factor of a transmission line and how does it affect electrical length?
Answer: It is the ratio of signal velocity in the line to the speed of light; a lower factor makes the line electrically longer
Velocity factor (VF) is the ratio of signal propagation speed in the line to the speed of light in a vacuum; a VF less than 1 means a physical length is electrically longer than the same length in free space.