Which of the following describes alternating current?
AnswerCurrent that alternates between positive and negative directions
Alternating current repeatedly reverses direction. During each cycle, current flows one way and then the opposite way.
MIX // TECH
Ham Feed
One question. One answer. Zero noise.
ONLY THE RIGHT ANSWER //No distractors. No scoring. No account. Just repeated exposure to what you need to know.
What is a band plan, beyond the privileges established by the FCC?
AnswerA voluntary guideline for using different modes or activities within an amateur band
A band plan is a voluntary operating convention that suggests where different modes and activities should take place within the frequencies the FCC authorizes.
What is a disadvantage of a handheld radio transceiver’s short flexible antenna compared to a full-sized quarter-wave antenna?
AnswerIt has low efficiency
A short flexible handheld antenna is much shorter than a full-sized quarter-wave radiator, so it generally converts less transmitter power into radiated RF.
Which of the following can reduce interference to a 2-meter band transceiver from a nearby commercial FM station?
AnswerInstalling a band-reject filter
A strong nearby FM broadcast signal can overload a 2-meter receiver. A band-reject filter attenuates the unwanted broadcast-band signal before it reaches the receiver.
When is it permissible to transmit messages encoded to obscure their meaning?
AnswerOnly when transmitting control commands to space stations or model craft
Messages encoded to obscure their meaning are permitted only for control commands to space stations or model craft.
When, other than during an emergency, may a Technician class licensee be the control operator of a station operating in an Amateur Extra Class band segment?
AnswerAt no time
Outside an emergency, a Technician class licensee may not be the control operator of a station transmitting in an Amateur Extra Class-only band segment.
Which region of the atmosphere can reflect HF radio waves?
AnswerThe ionosphere
The ionosphere contains charged particles that can refract or return HF signals toward Earth, allowing contacts well beyond the normal line-of-sight range.
Which of the following is a source of loss in coaxial feed line?
AnswerWater intrusion, high SWR, and multiple connectors can all contribute to coaxial feed-line loss.
Coaxial feed-line loss can increase because of water intrusion, mismatch-related current and voltage effects from high SWR, and additional connector losses.
Which of the following controls could be used if the voice pitch of a single-sideband signal returning to your CQ call seems too high or low?
AnswerThe RIT or Clarifier
Receiver Incremental Tuning, often labeled RIT or Clarifier, shifts the receive frequency slightly without changing the main transmit frequency. It is useful for making an SSB voice sound natural.
How much current is required to deliver 120 watts at a voltage of 12 volts DC?
Answer10 amperes
Rearrange P = E × I to I = P ÷ E. Dividing 120 watts by 12 volts gives 10 amperes.
Which of the following increases the resonant frequency of a dipole antenna?
AnswerShortening it
A resonant dipole becomes resonant at a higher frequency when its physical length is shortened, because resonant length is inversely related to frequency.
Which is equal to 3000 milliamperes?
Answer3 amperes
One ampere equals 1000 milliamperes. Therefore 3000 milliamperes equals 3 amperes.
What is the resistance of a circuit for which the applied voltage is 12 volts and the current flow is 1.5 amperes?
Answer8 ohms
Use R = E ÷ I. Dividing 12 volts by 1.5 amperes gives 8 ohms.
Besides an FCC-issued amateur operator license, what is required to be the control operator of a Radio Amateur Civil Emergency Service (RACES) Station?
AnswerCertification of current enrollment by a civil defense organization
To control a RACES station, an amateur must also have certification of current enrollment by a civil defense organization.
How is a voltmeter connected to a component to measure applied voltage?
AnswerIn parallel
Voltage is the difference in potential between two points. A voltmeter therefore connects across the component, in parallel.
In which direction does a half-wave dipole antenna radiate the strongest signal?
AnswerBroadside to the antenna
A half-wave dipole has its strongest radiation broadside to the wire and much weaker radiation off the ends.
What is the abbreviation for kilohertz?
AnswerkHz
The standard abbreviation for kilohertz uses a lowercase k, uppercase H, and lowercase z: kHz.
What is the relationship between the electric and magnetic fields of an electromagnetic wave?
AnswerThey are at right angles
A radio wave has electric and magnetic fields that are perpendicular to each other and also perpendicular to the direction the wave travels.
What is the unit of capacitance?
AnswerFarad
The standard unit of capacitance is the farad, named for Michael Faraday.
Which is true about forward voltage drop in a diode?
AnswerIt is lower in some diode types than in others
Different diode materials and constructions have different forward voltage drops. For example, a Schottky diode typically drops less forward voltage than a silicon junction diode.
Which of the following is a disadvantage of FM compared with single sideband?
AnswerOnly one signal can be received at a time
FM receivers exhibit a capture effect: when two signals arrive on the same frequency, the stronger one tends to dominate instead of both being heard clearly.
Which of the following can provide power gain?
AnswerTransistor
A transistor can control a larger output signal using a smaller input signal, which lets it provide amplification and power gain.
What type of current flow is opposed by resistance?
AnswerDirect current, alternating current, and RF current.
Resistance opposes current flow regardless of whether the current is direct, alternating, or at radio frequency.