Free Ham Radio Technician I Questions And Answers — Questions and Answers

Question 1: What qualifies as a defining feature of the FT8 mode of the WSJT-X family?

America, Boston, Canada, Denmark
Adam, Boy, Charles, David
Alpha, Bravo, Charlie, Delta (Correct answer)
Able, Baker, Charlie, Dog

Correct 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.

Question 2: Which of the following things affects a parallel conductor antenna feed line's characteristic impedance?

The distance between the centers of the conductors and the length of the line
The frequency of the signal and the length of the line
The distance between the centers of the conductors and the radius of the conductors (Correct answer)
The radius of the conductors and the frequency of the signal

Correct 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.

Question 3: To transform signals of multiple frequencies into an intermediate frequency (IF), which mixer input is adjusted or tuned?

Beat frequency oscillator
RF input
Image frequency
Local oscillator (Correct answer)

Correct 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.

Question 4: What frequency range, with the displayed carrier frequency set to 7.178 MHz, is occupied by a 3 kHz LSB signal?

7.175 to 7.178 MHz (Correct answer)
7.178 to 7.184 MHz
7.178 to 7.181 MHz
7.1765 to 7.1795 MHz

Correct 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.

Question 5: When the displayed carrier frequency is set to 7.178 MHz, what frequency range is occupied by a 3 kHz LSB signal?

7.178 to 7.181 MHz
7.178 to 7.184 MHz
7.175 to 7.178 MHz (Correct answer)
7.1765 to 7.1795 MHz

Correct 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.

Question 6: What are the bipolar transistor's stable operating points when employed as a switch in a logic circuit?

Its peak and valley current points
Its enhancement and depletion modes
Its active region (between the cutoff and saturation regions)
Its saturation and cutoff regions (Correct answer)

Correct 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.

Question 7: Which of the following prevents alternating current from flowing via an inductor?

Admittance
Reactance (Correct answer)
Conductance
Reluctance

Correct 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.

Question 8: 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?

Only the ground wire
Only the neutral wire
Only the two wires carrying voltage (Correct answer)
All wires

Correct 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.

Question 9: What is the name of the broad outer circle where the reactance arcs end on the Smith charts shown in Figure E9-3?

Prime axis
Reactance axis (Correct answer)
Impedance axis
Polar axis

Correct 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.

Question 10: Tri-state logic: what is it?

Propriety logic devices manufactured by Tri-State Devices
Low-power logic devices designed to operate at 3 volts
Logic devices that utilize ternary math
Logic devices with, 0, 1, and high-impedance output states (Correct answer)

Correct 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.

Question 11: Which transmitter operators and licensees are in charge of preventing overexposure situations at a location where several transmitters are active at once?

Each transmitter operating with a duty cycle greater than 50 percent
Each transmitter that produces 5 percent or more of its MPE limit in areas where the total MPE limit is exceeded (Correct answer)
Only commercial transmitters
Only the most powerful transmitter

Correct 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.

Question 12: What is one benefit of employing ferrite cores in an inductor over powdered iron?

Ferrite toroids are easier to use with surface mount technology
Ferrite toroids generally have better turns to produce a given inductance value (Correct answer)
Ferrite toroids generally have better temperature stability
Ferrite toroids generally have lower initial permeability

Correct 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.

Question 13: What qualifies as an Extended Double Zepp antenna?

An end-fed folded dipole antenna
A center-fed 1.25-wavelength antenna (two 5/8- wave elements in phase) (Correct answer)
A portable antenna erected using two push support poles
A wideband vertical antenna constructed from precisely tapered aluminum tubing

Correct 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.

Question 14: Reciprocal mixing is what?

Two out-of-band signals mix to generate an in-band spurious signal
In-phase signals canceling in a mizer resulting in loss of receiver sensitivity
Two digital signals combining from alternate time slots
Local oscillator phase noise mixing with adjacent strong signals to create interference to desired signals (Correct answer)

Correct 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.

Question 15: With the help of a digital signal processing noise filter, which of the following types of noise may be frequently reduced?

Broadband white noise
Ignition noise
Power line noise
All these choices are correct (Correct answer)

Correct 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.

Question 16: What time of year is it most likely that occasional E propagation will take place?

Around the solstices, especially the summer solstice (Correct answer)
Around the solstices, especially the winter solstice
Around the equinoxes, especially the spring equinox
Around the equinoxes, especially the fall equinox

Correct 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.

Free Ham Radio Technician I Questions And Answers

What qualifies as a defining feature of the FT8 mode of the WSJT-X family?