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 effect of increasing the number of elements in a Yagi antenna while keeping the boom length constant?
Answer: Element spacing decreases, which typically reduces gain compared to an optimally spaced design
Squeezing more elements onto a fixed boom reduces inter-element spacing, which generally lowers gain and degrades pattern compared to an optimally spaced Yagi with fewer elements.
What is a 'pi-network' tank circuit in a transmitter used for?
Answer: To match the amplifier's output impedance to the antenna feedline while providing harmonic suppression
A pi-network acts as both a low-pass filter to suppress harmonics and an impedance-matching network between the amplifier output and the transmission line.
What is 'auroral propagation' and which amateur bands does it most affect?
Answer: VHF and UHF reflection off the ionized aurora borealis, mainly affecting 50 MHz and above
Auroral propagation uses the ionized curtain of the aurora borealis as a reflector for VHF signals, most notably on the 6-meter and 2-meter bands.
Which parameter best describes the ratio of a power amplifier's output power to its DC input power?
Answer: Efficiency
Efficiency is the ratio of RF output power to DC input power, expressed as a percentage; higher efficiency means less heat dissipation for a given output power.
What document must an amateur station have available during an FCC inspection?
Answer: The current FCC license or a photocopy, or a displayed electronic copy
FCC rules require the station license (or an electronic or photocopy) to be available at the station for inspection; original paper is not mandated.
When computing the height of an antenna above 'effective ground' for ground-wave propagation, what soil condition produces the best results?
Answer: Salt water or very moist, rich agricultural soil
Salt water has extremely high conductivity (~4 S/m), minimizing ground-wave attenuation; rich moist soil is the next best, while rocky or sandy soils are poor conductors.
What is the purpose of an 'automatic level control' (ALC) circuit in an HF transceiver?
Answer: To prevent the transmitter from exceeding its rated peak envelope power by reducing drive when needed
ALC samples the transmitter's output power and feeds a control voltage back to the driver stage to reduce gain if the PEP would otherwise exceed the set maximum, protecting finals from overdrive.