Practice Test Flashcards
16 cards from real Ham Radio Technician Test practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 16 Practice Test flashcards as text
What qualifies as a defining feature of the FT8 mode of the WSJT-X family?
Answer: Alpha, Bravo, Charlie, Delta
The options provided are common phonetic alphabets used in radio communication. While not a direct 'defining feature' of the FT8 digital mode itself, the sequence 'Alpha, Bravo, Charlie, Delta' represents the standard NATO phonetic alphabet. This alphabet is universally recognized and used by amateur radio operators to clearly spell out call signs and other information, especially under noisy conditions.
Which of the following things affects a parallel conductor antenna feed line's characteristic impedance?
Answer: The distance between the centers of the conductors and the radius of the conductors
The characteristic impedance of a parallel conductor transmission line is determined by its physical geometry and the dielectric material between the conductors. Specifically, for a two-wire line, it depends on the diameter (or radius) of the conductors and the precise spacing between their centers. These physical dimensions dictate the line's inductance and capacitance per unit length, which in turn define its characteristic impedance.
To transform signals of multiple frequencies into an intermediate frequency (IF), which mixer input is adjusted or tuned?
Answer: Local oscillator
In a superheterodyne receiver, the local oscillator (LO) generates a signal that is mixed with the incoming radio frequency (RF) signal. By adjusting the frequency of the local oscillator, the mixer produces a fixed intermediate frequency (IF) signal, which is the difference (or sum) between the RF and LO frequencies. This allows the receiver to tune to different stations while processing all signals at a consistent, optimized IF.
What frequency range, with the displayed carrier frequency set to 7.178 MHz, is occupied by a 3 kHz LSB signal?
Answer: 7.175 to 7.178 MHz
LSB stands for Lower Sideband, meaning the signal occupies frequencies below the carrier frequency. A 3 kHz LSB signal with a displayed carrier of 7.178 MHz will extend 3 kHz downwards from the carrier. Therefore, the occupied frequency range will be from 7.178 MHz minus 0.003 MHz (3 kHz), which is 7.175 MHz, up to the carrier frequency of 7.178 MHz.
When the displayed carrier frequency is set to 7.178 MHz, what frequency range is occupied by a 3 kHz LSB signal?
Answer: 7.175 to 7.178 MHz
LSB (Lower Sideband) signals occupy frequencies below the carrier. For a 3 kHz LSB signal centered at a displayed carrier frequency of 7.178 MHz, the signal bandwidth extends 3 kHz downwards from the carrier. Thus, the occupied frequency range is from 7.178 MHz minus 3 kHz (0.003 MHz), which equals 7.175 MHz, up to the carrier frequency of 7.178 MHz.
What are the bipolar transistor's stable operating points when employed as a switch in a logic circuit?
Answer: Its saturation and cutoff regions
When a bipolar transistor is used as a switch in a logic circuit, it operates in two distinct states: 'on' or 'off.' The cutoff region represents the 'off' state, where the transistor acts as an open circuit with virtually no current flow. The saturation region represents the 'on' state, where the transistor is fully conducting and acts like a closed switch with minimal voltage drop, providing the stable, distinct states required for digital logic.
Which of the following prevents alternating current from flowing via an inductor?
Answer: Reactance
Inductors oppose changes in current flow, and this opposition to alternating current (AC) is known as inductive reactance. Unlike resistance, which dissipates energy, reactance stores and releases energy. As the frequency of the AC signal increases, an inductor's inductive reactance also increases, making it more effective at impeding or blocking the flow of AC.
In a device powered by a 240 VAC single phase source, which wire(s) in a four-conductor connection should be connected to fuses or circuit breakers?
Answer: Only the two wires carrying voltage
In a 240 VAC single-phase system, fuses and circuit breakers are safety devices designed to protect against overcurrent by interrupting the flow of electricity. They must be connected to the 'hot' or live conductors, which are the two wires carrying voltage relative to ground. Placing them on the neutral or ground wire would not effectively protect the circuit or device from overcurrent conditions.
What is the name of the broad outer circle where the reactance arcs end on the Smith charts shown in Figure E9-3?
Answer: Reactance axis
On a Smith chart, the broad outer circle represents the locus of points where the resistance component of impedance is zero. Along this circle, the impedance is purely reactive, meaning it consists only of inductive or capacitive reactance. Therefore, this outer boundary is referred to as the reactance axis, where the normalized resistance (r) is zero.
Tri-state logic: what is it?
Answer: Logic devices with, 0, 1, and high-impedance output states
Tri-state logic refers to digital circuits that can have three distinct output states: logic 0 (low voltage), logic 1 (high voltage), and a high-impedance (Hi-Z) state. In the high-impedance state, the output effectively disconnects from the circuit, presenting a very high impedance. This allows multiple devices to share the same bus without interference, as only one device actively drives the bus at a time.
Which transmitter operators and licensees are in charge of preventing overexposure situations at a location where several transmitters are active at once?
Answer: Each transmitter that produces 5 percent or more of its MPE limit in areas where the total MPE limit is exceeded
FCC regulations for RF exposure state that when multiple transmitters are active at a single location, responsibility for ensuring compliance with Maximum Permissible Exposure (MPE) limits is shared. Any licensee whose transmitter contributes 5% or more of the MPE limit in an area where the total MPE limit is exceeded is jointly responsible for taking corrective action to prevent overexposure, ensuring collective accountability for safety.
What is one benefit of employing ferrite cores in an inductor over powdered iron?
Answer: Ferrite toroids generally have better turns to produce a given inductance value
Ferrite materials generally possess much higher magnetic permeability compared to powdered iron. This higher permeability means that fewer turns of wire are required on a ferrite core to achieve a specific inductance value. This advantage allows for the creation of smaller, more efficient inductors, particularly beneficial in high-frequency applications.
What qualifies as an Extended Double Zepp antenna?
Answer: A center-fed 1.25-wavelength antenna (two 5/8- wave elements in phase)
An Extended Double Zepp antenna is a type of wire antenna designed for enhanced gain. It consists of two 5/8-wavelength elements fed in phase at the center, resulting in a total length of approximately 1.25 wavelengths. This configuration provides significant gain over a standard half-wave dipole, especially at lower radiation angles, making it effective for long-distance communication.
Reciprocal mixing is what?
Answer: Local oscillator phase noise mixing with adjacent strong signals to create interference to desired signals
Reciprocal mixing is a receiver phenomenon where phase noise from the local oscillator (LO) mixes with strong, nearby interfering signals. This mixing process generates noise sidebands that can fall within the receiver's passband, effectively raising the noise floor and degrading the reception of weak desired signals. It occurs even if the interfering signal itself is outside the receiver's nominal passband.
With the help of a digital signal processing noise filter, which of the following types of noise may be frequently reduced?
Answer: All these choices are correct
Digital Signal Processing (DSP) noise filters are highly effective and versatile tools in radio communication. They can utilize sophisticated algorithms to identify and reduce various types of noise, including broadband white noise, impulsive noises like ignition noise from vehicles, and periodic disturbances such as power line noise. Therefore, DSP filters can significantly improve signal clarity across a wide range of noise sources.
What time of year is it most likely that occasional E propagation will take place?
Answer: Around the solstices, especially the summer solstice
Sporadic E (Es) propagation is a phenomenon where patches of unusually ionized E-layer in the ionosphere reflect radio waves, enabling long-distance communication on VHF and higher HF bands. This type of propagation is most prevalent during the summer months in both hemispheres, peaking around the summer solstice, due to increased solar radiation and atmospheric conditions conducive to E-layer ionization.