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 does the term 'third-order intercept point' (IP3) indicate about an RF amplifier?
Answer: A measure of the amplifier's linearity and resistance to intermodulation distortion
IP3 is a theoretical extrapolation that quantifies an amplifier's linearity; a higher IP3 means less intermodulation distortion at a given input power.
Which digital mode was specifically designed for weak-signal meteor-scatter and EME communication?
Answer: JT65
JT65, developed by Joe Taylor K1JT, was designed for extremely weak signals and is widely used for EME (moon-bounce) and weak-signal VHF/UHF work.
What is the relationship between skin depth and frequency in a conductor?
Answer: Skin depth decreases as frequency increases
Skin depth decreases as frequency increases because the skin effect forces current to flow closer to the conductor's surface at higher frequencies.
What is the function of a 'noise blanker' in a receiver?
Answer: To detect and suppress short-duration impulse noise pulses
A noise blanker samples the incoming signal, detects impulse noise spikes (such as ignition noise), and briefly mutes the receiver during each pulse.
When operating through a satellite repeater, why must operators use the minimum power necessary?
Answer: Excessive power desensitizes the satellite's receiver and degrades the link for others
Satellite linear transponders are shared resources; using excess power captures more of the transponder's dynamic range and causes AGC-driven gain reduction that affects all other users.
In terms of feed-point impedance, how does a folded dipole differ from a standard half-wave dipole?
Answer: The folded dipole has approximately 300 ohms impedance versus about 73 ohms for a standard dipole
A folded dipole has approximately 300 ohms feed-point impedance, which is about four times that of a standard half-wave dipole, making it a natural match for 300-ohm twinlead.
What is the primary advantage of using a phase-locked loop (PLL) synthesizer for VFO frequency generation?
Answer: Crystal-referenced frequency stability with continuous tuning
A PLL synthesizer locks a voltage-controlled oscillator to a stable crystal reference, combining the frequency stability of a crystal with the continuous tuning of a VFO.