NTC Class C Element 4 (IV)

[Information] : Where a question shows [Information]. All the information given below that question is OK

Why is an antenna tuner (Antenna Tuning Unit - ATU) used?
1. to increase the SWR of antenna
2. to lower the transmitter output
3. to increase the transmitter output
4. to effect good impedance match between transmitter and antenna
What does an S-meter measure?
1. resistance
2. received signal strength
3. inductance
4. impedance
Dummy Load : [Information]
1. A dummy load is used instead of an antenna when a transceiver is tested or adjusted
2. A dummy load is a resistive component that absorbs all the output power of an electrical generator or radio transmitter.
  The dummy antenna is connected to the output of a radio transmitter and electrically simulates an antenna to allow the transmitter to be adjusted and tested without radiating radio waves.
3. The dummy load ordinarily should be a pure resistance; the amount of resistance should be the same as the impedance of the antenna or transmission line that is used with the transmitter (usually 50 Ω or 75 Ω) :The ideal dummy load provides a standing wave ratio (SWR) of 1:1 at the given impedance.
4. A dummy load must be chosen or designed to tolerate the amount of power that can be delivered by the transmitter
Power Measurement: [Information]
1. Standard RF power measurements are conducted using a non-radiating artificial antenna (dummy load) with a standard impedance of 50 ohms. The load should be capable of handling the rated power of the transmitter to be measured.
2. The measurement device can be a combined indicating meter and artificial antenna or a combination standing wave ratio (SWR) meter and a separate artificial antenna. All measurements are only valid if the SWR is equal to 1:1
3. Transmitter controls such as compression device should be de-activated. The setting of Microphone gain and Drive controls should be in accordance with the manufactures recommendations
How can amateur station equipment best be protected from lightening damage?
1. Never turn off the equipment
2. Use heavy insulation for the wiring
3. Disconnect the ground system from all radios
4. Disconnect all equipment from the power lines and antenna cables
The frequency band most useful for SSB communication is
1. HF
2. VHF
3. UHF
4. SHF
Frequency meter :
1. Frequency meter is a device for measuring the repetitions per unit of time (customarily, a second) of a complete electromagnetic waveform (frequency).
Instrument used to measure resistance with value less than one ohm
1. multimeter
2. ohmmeter
3. Wheatstone bridge
4. resistance bridge
A multimeter or a multitester, also known as a VOM, is an electronic measuring instrument that combines several measurement functions in one unit. A typical multimeter can measure voltage, current, and resistance.
1. Ok
Which of the following devices would you need to conduct Amateur Radio communications using a data emission?
1. Transceiver
2. Transvertor
3. Computer
4. Internet connection
Instrument used to measure voltage in an electrical circuit
1. galvanometer
2. ohmmeter
3. voltmeter
4. thermocouple
What term describes the process of combining an information signal with a radio signal?
1. Modulation
2. Demodulation
3. Super modulation
4. Single modulation
Intermodulation interference is the undesired combining of several signals in a nonlinear device, producing new, unwanted frequencies, which can cause interference in adjacent receivers located at repeater sites
1. Ok
How is an ammeter usually connected to a circuit?
1. With clips
2. In parallel
3. With copper wire
4. In series
What is used to effect good impedance match between the transmitter and the antenna?
1. coax cable
2. resistometer
3. antenna coupler (ATU)
4. SWR meter
What RF-safety precautions should you take before beginning repairs on an antenna?
1. Inform your neighbors so they are aware of your intentions
2. Turn off the main power switch in your house
3. Be sure you and the antenna structure are grounded
4. Be sure to turn off the transmitter and disconnect the feedline
What is the instrument that measure high and low states of ICs?
1. VTVB
2. logic probe
3. thermocouple
4. grid dip meter
What instrument is used to measure standing wave ratio?
1. A voltmeter
2. A SWR meter
3. A resistance meter
4. A inductance meter
Direction finding: [Information]
1. Direction finding (DF) or radio direction finder (RDF) is a device for finding the direction, or bearing, to a radio source from which a received signal was transmitted.
2. A receiver to hear the targeted transmitted signal, a directional antenna system which used to determine the direction of the source of a signal.The directional antenna system can be hand held.A compass will show from which direction (heading) the directional antenna is receiving the strongest signal.
3. Triangulation : Direction finding (DF) refers to the establishment of the direction from which a received signal was transmitted. Each receiver uses a directional antenna to determine the angle from at which the signal was received.
  By combining antenna headings from several different receiving locations to locate the signal source, the source of a transmission may be located via triangulation.
What does the term "Frequency Stability Over Temperature means"
1. Frequency tolerance with respect to a range of temperature measured in PPM or Parts Per Million
2. This specification is intended for RF amplifiers
3. The higher the PPM value the better is the stability
4. It measures the gain with respect to temperature
Ability of a circuit to discriminate against different signals
1. selectivity
2. S/N ratio
3. S/D ratio
4. sensitivity
If a single-sideband phone transmitter is 100% modulated, what will a speech processor do to the transmitter's power?
1. It will decrease the average power output
2. It will decrease the peak output power
3. It will add nothing to the output PEP
4. It will increase the output PEP
In what radio frequency range do 2-meter communications take place?
1. HF
2. MF
3. UHF
4. VHF
Which frequency is within the 6-meter band?
1. 48 MHZ
2. 28 MHZ
3. 52 MHZ
4. 75 MHZ
Most humans can hear sounds in what frequency range?
1. 10 - 100 hz
2. 20 - 20,000 hz
3. 20 - 30,000 hz
4. 30 hz - 5 mhz
What circuit blocks RF energy above and below certain limits?
1. A band-pass filter
2. A high-pass filter
3. A low-pass filter
4. A series filter
Which of the following controls could be used if the voice pitch of a single-sideband signal seems too high or too low?
1. RF volume control
2. Change bandwidth
3. The receiver RIT or clarifier
4. Adjust VFO
What is a coaxial cable?
1. two copper wires
2. flat television cable
3. A center wire inside an insulating material covered by a metal sleeve or shield
4. mains cable
Frequency Counter : [Information]
1. To measure the Frequency of an Audio Oscillator
2. To measure the frequency of an RF Oscillator
3. Measure the reference frequency in a PLL circuit
What is a logic probe?
1. A probe to detect metal objects
2. A probe for detecting underwater objects
3. A probe used for analyzing and troubleshooting logical states.
4. A probe for measuring changes in ambient temperature
Which of the following is a common use for the dual VFO feature on a transceiver?
1. To permit transmitting on two different bands
2. To permit two frequencies to be monitored at the same time
3. To permit the monitoring of the transmit and receive frequencies when they are not the same
4. To permit computer interface connection
What is cross-modulation?
1. Modulation produced after passing through a zero-crossing detector
2. Modulation based on the zero-crossings of an RF signal
3. The transfer of the amplitude modulation of a strong unwanted carrier onto the wanted carrier caused by non-linearity in the RF amplifier or mixer of a receiver
4. Modulation which is a cross between an AM and FM mode
What is intermodulation interference?
1. Interference caused by signals arriving from different paths.
2. Interference caused by a shift in the carrier frequency of an AM transmitter.
3. Interference caused by the combining several signals in a non-linear device producing new unwanted frequencies.
4. Interference caused by odd order harmonics of a transmitter's fundamental frequency.
The stage in an SSB operational transmitting system where distortion most likely occurs
1. final amp
2. buffer amp
3. modulator
4. oscillator
Which of the following statements about station grounding is true?
1. If the chassis of all station equipment is connected with a good conductor, there is no need to tie them to an earth ground
2. RF hot spots can occur in a station located above the ground floor if the equipment is grounded by a long ground wire
3. A ground loop is an effective way to ground station equipment
4. The chassis of each piece of station equipment should be tied together with high-impedance conductors
Which of these connector types is commonly used for audio signals in Amateur Radio
1. PL-259
2. RCA Phono
3. SO-239
4. BNC
A "TR" switch means?
1. A Transfer relay switch
2. Transmit-Receive change-over switch
3. A Telephone Receiver switch
4. A Telephone Response switch
How could you best keep unauthorized persons from using your amateur station at home?
1. Use a padlock
2. Use a key-operated on/off switch in the main power line
3. Buy a Aso
4. Erect High Voltage - Keep Out signs
Which of the following can be used to enter the operating frequency of a modern transceiver?
1. Channel selector
2. Automatic frequency control
3. Shift knob
4. The keypad or VFO knob
What are the typical characteristic impedances of coaxial cables used for antenna feed lines at amateur stations?
1. 25 ohms and 30 ohms
2. 300 ohms and 450 ohms
3. 75 ohms and 100 ohms
4. 50 ohms and 75 ohms
Which of the following is true concerning access to frequencies?
1. QSO's in process always have priority
2. Nets always have priority
3. Contest operations must always yield to non-contest use of frequencies
4. No one has priority access to frequencies, common courtesy should be a guide
To generate pulsating DC voltage, what equipment is used?
1. RF generator
2. Hartley oscillator
3. quartz generator
4. sweep generator
What is frequency drift? [Information]
1. Unintended and arbitrary offset of an oscillator from its nominal frequency
2. Measured either in the long-term or short-term period of time
3. It is caused by changes in temperature, voltage or changes in component values
What is capture effect?
1. A phenomenon in FM reception in which only the stronger of two signals at, or near, the same frequency will be demodulated.
2. This phenomenon is inherent in AM modulation.
3. The capturing of electrons in a vacuum tube by the plate electrode.
4. Wideband antennas have this characteristic effect.
Signal Tracer: A signal tracer is a piece of electronic test equipment used to troubleshoot radio and other electronic circuitry.
1. A signal tracer device normally provides an amplifier, and a loudspeaker, often battery-powered and packaged into a small, hand-held test probe. An optional diode detector is usually also provided, allowing the detection of amplitude-modulated signals.
Two -Tone Test : [Information]
1. The measure of linearity of SSB transceivers and linear amplifiers often requires a standard two-tone (700 and 1900 Hz) audio source. Linearity impacts both SSB fidelity and the amount of SSB splatter that causes adjacent channel interference
2. Two Tone test generator provides a standard 2-tone (700 and 1900 Hz)
  audio source. This type of testing is most commonly used as a measure of transmitter linearity for amateur radio equipment
3. What does a two-tone test illustrate on an oscilloscope?
  Linearity of a SSB transmitter.
Signal generator
1. generates pulsating DC voltage
2. used to measure resistance less than one ohm
3. designed to produce AF & RF bands
4. used for monitoring relative RF output during transmitter & antenna adjustment
Which of the following can be determined with a field strength meter?
1. The strength of a transmitter
2. The radiation resistance of an antenna
3. The radiation pattern of an antenna
4. The measurment of inductance pattern
What is the purpose of the VOX sensitivity control?
1. To set the audio level of the microphone
2. To set the audio level at which the transmitter activates
3. To set the audio frequency range at which the transmitter activates
4. To set the speed of the morse code to be sent
Logic probe. {Information]
1. A logic probe is a test probe used for analyzing and troubleshooting the logical states (boolean 0 or 1) of a digital circuit.
2. Red High logic state a binary 1: The logic probe / digital logic tester is able to detect lines that are at the digital or logic high state. The logic probe will indicate this typically with an LED which is often coloured red.
3. Green: Low logic state a binary 0: The logic probe also is able to indicate a logic or digital low. A common indication is the use of a green coloured LED.
4. Amber (Yellow) : Digital pulses.The logic probe may incorporate some form of pulse detection circuitry. When the line is active and being pulsed a third colour, possibly a amber LED will be indicated.
What is used to test the linearity and output power of an SSB transceiver?
1. Single-tone sine wave test
2. Two-tone sine wave test
3. Single-tone square wave test
4. Three-tone sine wave test
What instrument is used to present test signals in frequency domain?
1. frequency meter
2. spectrum analyzer
3. digital oscilloscope
4. logic probe
What type of instrument can be used to measure a RF field?
1. Field-strength meter
2. Dummy load meter
3. Receiver S meter
4. SWR meter
What is receiver desensitization?
1. The receiver is not tuned to the correct frequency
2. Defective RF amplifier in the receiver
3. Overloading of a receiver front-end by a strong off-channel signal causing a reduction in sensitivity
4. When the receiver front-end is misaligned
To increase the capacitance of a capacitor add _______
1. An inductor in series
2. A capacitor in parallel
3. A capacitor in series
4. A resistor in parallel
The origin of interfering signal can be located with the use of a direction finder by
1. Triangulation
2. Sky wave
3. Ground wave
4. Biangulation
What type of filter should be connected to a TV receiver as the first step in trying to prevent RF overload from a nearby 2 M transmitter?
1. LP filter
2. HP filter
3. BP filter
4. Band reject filter
Which of the following measurements are commonly used using a multimeter?
1. SWR and RF power output
2. Voltage and resistance
3. Noise and signal strength
4. Inductance and impedence
What could be a symptom of a ground loop somewhere in your station?
1. The SWR reading for one or more antennas is suddenly very high
2. An item of station equipment starts to draw excessive amounts of current
3. You receive reports of "hum" on your station's transmitted signal
4. You receive reports of harmonic interference from your station
What may happen if an SSB transmitter is operated with the microphone gain set too high?
1. It may cause interference to other stations operating on a higher frequency
2. It may cause digital interference to computer equipment
3. It may cause splatter interference to other stations operating near its frequency
4. It may cause atmospheric interference in the air around the antenna
If a signal covers the frequency 14200 to 14250 kHz what is the bandwidth?
1. 50 khz
2. 60 khz
3. 70 khz
4. 80 khz
What does a spectrum analyzer test instrument display?
1. Spectral composition of light
2. Spectral analysis of elements
3. Frequency domain waveforms
4. Time domain waveforms
What might cause erratic changes in SWR readings?
1. The transmitter has a problem
2. Negative feedback
3. Speech modulation
4. A loose connection in an antenna or a feedline
What signals are used to conduct a two-tone test?
1. Two non-harmonically related audio signals
2. Two audio frequency range square wave signals
3. Two audio signals of the same frequency
4. Two swept frequency tones
What is an advantage of a digital voltmeter as compared to an analog voltmeter?
1. Faster response
2. Better for measuring computer circuits
3. Better precision for most uses
4. Better for RF measurements
Which of the following precautions should be taken when measuring circuit resistance with an ohmmeter
1. Ensure that the circuit is grounded
2. Ensure that the applied voltages are correct
3. Ensure that the circuit is not powered
4. Ensure that the circuit is operating at the correct frequency
Why is it best not to draw the DC power for a 100-Watt HF transceiver from an automobile's cigarette lighter socket?
1. The DC polarity of the socket is reversed from the polarity of modern HF transceiver
2. The socket's wiring may not be adequate for the current being drawn by the transceiver
3. The power from the socket is never adequately filtered for HF transceiver operation
4. The socket is not wired with an RF-shielded power cable
What is normally meant by operating a transceiver in "split" mode?
1. The radio is operating at half power
2. The transceiver is set to different transmit and receive frequencies
3. The transmitter is emitting a SSB signal, as opposed to DSB operation
4. The transceiver is operating from an external power source
Frequency band used by an AM broadcast station when the radio dial is 860 kHz
1. Medium Frequency
2. High Frequency
3. Very High Frequency
4. Ultra High Frequency
Which instrument is used to measure electrical current?
1. Voltmeter
2. Ammeter
3. Ohmmeter
4. Impedence meter
Audio rectification interference:
1. Audio rectification interference occurs when an electronic circuit (usually an amplifier), which ideally should respond only to audio frequency signals, responds to external radio frequency (RF) signals. Typically, the circuit picks up signals from a nearby radio transmitter in addition to the sound the listener wants to hear. The unwanted signal may be constant or intermittent, faint or uncontrollably loud.
If you are told your amateur station is causing television interference, what should you do?
1. First make sure your station is operating properly, and it does not cause interference to your own television
2. Continue operating normally, because you have no reason to worry about the interference
3. Immediately turn off your transmitter and contact the nearest NTC office
4. Connect a high-pass filter to the transmitter output and low-pass filter to the antenna input of the television
If you are the net control station of a daily HF net, what should you do if the frequency on which you normally meet is in use just before the net begins?
1. Cancel the net for the day
2. Conduct the net on a clear frequency 3 to 5 kHz away from the regular net frequency
3. Increase your power output so that the net participants will be able to hear you over the existing activity
4. Reduce your output power and start the net as usual
What popular operating activity involves contacting as many stations as possible during a specified period of time?
1. Contesting
2. Club Nets
3. DXing
4. Check in
Electrical wiring safety: [Information]
1. To protect you against electrical shock, the chassis of each piece of your station equipment should be connected to...
  A good ground connection
2. On mains operated power supplies, the ground wire should be connected to the metal chassis of the power supply. This ensures, in case there is a fault in the power supply, that the chassis......does not develop a high voltage with respect to the ground
3. Why would there be a switch in a high voltage power supply to turn off the power if its cabinet is opened....To keep anyone opening the cabinet from getting shocked by dangerous high voltages
4. Fuse box controls the electrical flow to your home....... In the event of an overload, the fuse attached to that circuit will blow.....This will cut power to every device on that circuit in the house....... They protect you and your home from electrical fires and other problems.......Most boxes have a main switch that will control power to the entire house.
What reading on an SWR meter indicates perfect impedance match between the antenna and the feedline?
1. 2:1
2. 1:1
3. 5:1
4. 3:1
Where must a filter be installed to reduce harmonic emissions?
1. Between the transmitter and the antenna
2. Between the power supply and the transceiver
3. At the microphone
4. Between the receiver and the transmitter
Which of the following is an advantage of a switched-mode power supply as compared to a linear power supply?
1. The relatively high frequency power oscillator allows the use of small, light weight and low-cost transformers in the switched-mode supply
2. Higher output voltages are possible with the switched-mode supply
3. Fewer circuit components are required for the switched-mode power supply
4. Has greater efficiency than linear regulators
How can a ground loop be avoided?
1. Connect the AC neutral conductor to the ground wire
2. Avoid using lock washers and star washers when making ground connections
3. Connect all ground connections in series
4. Connect all ground contacts to a single point
What is the minimum safe distance from a power line when installing an antenna?
1. As far as possible away from the height of the power line
2. The antenna length divided by two
3. So that if the antenna falls unexpectedly, no part of it can come closer than 10 feet to the power wires
4. 1/2 wavelength at the operating frequency
Spectrum Analyzer: [Information]
1. A spectrum analyzer measures the magnitude of an input signal versus frequency within the full frequency range of the instrument
2. The purpose of a spectrum analyzer is to provide a plot or trace of signal amplitude against frequency.
Frequency 430 MHz is within the frequency band called
1. UHF
2. SHF
3. EHF
4. VHF
Speech Processor: The purpose of a speech processor as used in a modern transceiver is to increase the intelligibility of transmitted phone signals during poor conditions. It also increases average power of a transmitted single sideband phone signal. [Information]
1. the speech processor must be properly adjusted to gain the above benefits.
2. the effects of an incorrectly adjusted speech processor.
  1.Distorted speech.
  2.Splatter.
  3.Excessive background pickup.
A Grid-dip (GDO) meter measures_______
1. Feedback
2. Transmitter power output
3. Antenna impedence
4. Resonant frequency of an LC tank circuit
What is the best instrument to use to check the signal quality of a CW or single-sideband phone transmitter?
1. A monitoring oscilloscope
2. A sidetone monitor
3. A field-strength meter
4. A signal tracer and an audio amplifier
What is the purpose of a transmitter power supply interlock?
1. To ensure that dangerous voltages are removed if the cabinet is opened
2. To prevent unauthorized access to a transmitter
3. To prevent the transmitter from being remove
4. To prevent the power supply from being switched on accidently
Dummy antenna is used to:
1. to reduce standing waves
2. to prevent unnecessary radiation that may cause interference
3. match the antenna
4. reduce power
What brief statement is often used in place of "CQ" to indicate that you are listening on a repeater
1. Say "Hello testing" followed by your call sign
2. Say your call sign
3. Say the repeater call sign followed by your call sign
4. Say the letters "QRZ" followed by your call sign
It is an instrument that measures the relative power being radiated from an antenna
1. Volt meter
2. SWR meter
3. Reflector meter
4. Field strength meter
Which of the following may be useful in correcting a radio frequency interference problem?
1. Band-reject and band-pass filters
2. Snap-on ferrite chokes
3. Low-pass and high-pass filters
4. All the above is correct
What does an antenna tuner do?
1. Allows an antenna to be used on both transmit and receive
2. Matches the antenna system impedance to the transceiver's output impedance
3. Automatically selects the proper antenna for the frequency band being used
4. Helps a receiver automatically tune in weak stations
Call signs are transmitted to:
1. Show location
2. Clear the frequency
3. Identify the originator of message
4. Cause interference
What is frequency tolerance?
1. Detuning of receiver front-end caused by overload
2. Ability to recover from frequency changes
3. Ability to tolerate shock and vibration
4. Initial deviation of a crystal or oscillator frequency as compared to the absolute at 25 deg. C.
Final Ampifier Neutralizing: [Information]
1. The reason for neutralizing the final amplifier stage of a transmitter is to eliminate self-oscillations. This neutralization is done by returning a portion of the amplifier output back into the input in such a way that the signal is 180 degrees out of phase.
2. Q : What is the reason for neutralizing the final amplifier stage of a transmitter?
  A:To eliminate parasitic oscillations. Parasitic oscillations generally produce a large number of harmonics.
3. Q : What does a neutralizing circuit do in an RF amplifier?
  A : It cancels the effects of positive feedback
Connect a resistor in series with a meter to ________ the measuring range of a voltmeter.
1. Increase
2. Decrease
3. Extend
4. Maintain
The interference brought by the resultant signal from addition and subtraction of the fundamental and harmonics of two or more signals is called
1. positive modulation
2. negative modulation
3. intermodulation
4. semi moduation
What does the term "Receiver Sensitivity" means?
1. It is the ability of a receiver to overcome strong signals
2. It is a measure of a receiver's ability to re-produce very weak signals
3. It is a measure of a receiver's ability to re-produce the modulation exactly as it was transmitted
4. It is the ability of a receiver to discriminate against off frequency signals
Which HF antenna would be the best to use for minimizing interference?
1. Vertical
2. Dipole
3. End fed
4. A unidirectional antenna
What is the characteristic of the current flow in a series RLC circuit at resonance
1. It is halved
2. It is minimum
3. It is maximum
4. It is doubled
What, in general terms, is standing wave ratio (SWR)?
1. The transmitter efficiency ratio
2. The ratio of high to low impedance in a feedline
3. An indication of the quality of your station's ground connection
4. A measure of how well a load is matched to a transmission line
What is an important safety precaution to take when putting up an antenna tower?
1. Use a ladder
2. Ground the tower
3. Look for and stay clear of any overhead electrical wires
4. Wear a safety helmet
Vehicle noise suppression: [Information]
1. Vehicle ignition noise: Buzzing that varies with engine speed, which is caused by arcing in the ignition system.
2. A noise blanker on a receiver is an effective way to reduce ignition noise.
Considering RF safety, what precaution should you take whenever you make adjustments to the feed line of a directional antenna system?
1. Wear a dosimeter
2. Lock the antenna brake
3. Wear safety gloves
4. Be sure no one can activate the transmitter
Tendency of RF current to flow along the surface of wire at high frequencies
1. Faraday’s effect
2. Skin effect
3. Magnetic
4. Smooth effect
Which of the following is common practice during net operations to get the immediate attention of the net control station when reporting an emergency?
1. Play a pre-recorded emergency alert tone followed by your call sign
2. Repeat the words SOS three times followed by the call sign of the reporting station
3. Begin your transmission with "Priority" or "Emergency" followed by your call sign
4. Press the push-to-talk button three times
The logarithm of the ratio of the output power over the input power is
1. Biobel
2. centibel
3. Decibel
4. DoorBel
Converting Frequency in Mhz to Wavelength in meters : [Information]
1. Frequency to Wavelength : 300 divided by Wavelength (meters): 30 mhz to Wavelength (meters) = 300 / 30 = 10 meters
2. Wavelength to frequency : 40 meters to frequency : 300 / 40 = 7.5 Mhz
3. 2 meters = 300 / 2 = 150 Mhz
4. 150MHz = 300 / 150 = 2 meters
What would be the SWR if you feed a vertical antenna that has a 25-ohm feed point impedance with 50-ohm coaxial cable?
1. 3:1
2. 2:1
3. 1:1
4. 1.5:1
Phonetic Alphabet is commonly used in radio communications because it:
1. Easy to remember
2. Useful
3. Ensure words are clearly understood
4. Reduce transmission time
What should you do if you receive a report that your station's transmissions are causing splatter or interference on nearby frequencies?
1. Check your transmitter for off-frequency operation or spurious emissions
2. Report the interference to the equipment manufacturer
3. Change mode of transmission
4. Increase transmit power
What does the term "Selectivity" means?
1. It is the ability to select different transmitter channels
2. It is the ability of a receiver to distinguish between a signal at the desired frequency and signals at adjacent frequencies
3. It is the ability to be able to select the transmitter output.
4. It is the ability to choose different antennas to use
An electrical circuit with a predominantly inductive reactance has a
1. positive power factor
2. negative power factor
3. lagging power factor
4. None of the above
An electrical current which changes polarity periodically is called
1. Positive current
2. Direct current
3. Half current
4. Alternating current
Harmonic Interference [Information]
1. Harmonics are undesired transmissions that are multiples of the intended transmission frequency.... Almost all RF transmitters produce some harmonics at low power levels, as compared to the fundamental frequency that is the desired transmission frequency.
  Harmonics produced by an ill functioning amateur radio transmitter may lie well outside of the amateur frequency bands and cause interference to other radio services or electronic devices... Harmonics are another potential cause of radio frequency interference.
2. A harmonic is a multiple of a single frequency — this single frequency is usually referred to as the fundamental frequency or sometimes the first harmonic. Using f as the fundemental frequency
  1st harmonic = 1 x f = fundamental frequency
  2nd harmonic = 2 x f
  3rd harmonic = 3 x f etc
  
  Example : If the fundemental transmission frequency is 28Mhz then the 2nd harmonic would be 2 x 28Mhz = 56Mhz which is Television Channel 2 (55.25 MHz) in the Philippines.... and may cause interference to those viewing Channel 2.
What does a two-tone test illustrate on an oscilloscope?
1. Side band suppression
2. Linearity of a SSB transmitter.
3. Signal output
4. Check the microphone
What does "repeater offset" mean ? [Information]
1. The difference between a repeater's transmit frequency and its receive frequency.....2 meters has a standard offset of 600KHz
If the transmitter output is not matched with the antenna, what will be the effect aside from reduced power?
1. Warm antenna feeder
2. Radiation of harmonic frequencies
3. High resistance
4. Parasitic oscillation
What are the frequency limits of the 2-meter band in ITU Region 3 ?
1. 144.000 - 148.000 MHz
2. 144.000 - 147.000 MHz
3. 144.000 - 147.500 MHz
4. 144.000 - 146.000 MHz
Which of these items would be useful for a hidden transmitter hunt?
1. A directional antenna
2. Field strength meter
3. Calibrated SWR meter
4. Grid Dip meter
An oscilloscope displays signals in what format?
1. Signal to noise ratio
2. Amplitude level and time duration
3. Noise floor of the signal
4. Amplitude level and frequency span
What is the second harmonic of 1200 Hz
1. 600 Hz
2. 2400 Hz
3. 600 Khz
4. 3600 Khz
What SWR among those mentioned shows the worst impedance match between transmission line and antenna?
1. 2:1
2. 5:1
3. 3:1
4. 1:1
If it is 1 AM in Manila, what is the Universal Standard time?
1. 15:00
2. 16:00
3. 17:00
4. 18:00
Standing-wave ratio (SWR) is a mathematical expression of the non-uniformity of an electromagnetic field (EM field) on a transmission line such as coaxial cable. Usually, SWR is defined as the ratio of the maximum radio-frequency (RF) voltage to the minimum RF voltage along the line. ... The ideal VSWR is therefore 1:1.
1. Ok
Field Strength Meter : Watt meter : SWR Meter: Grid Dip Meter (Grid Dip Oscillator - GDO) : [Information]
1. Field Strength Meter: In telecommunications, a field strength meter is an instrument that measures the electric field strength emanating from a transmitter and is commonly expressed in millivolts per meter (mV/m) or microvolts per meter (μV/m)
2. Wattmeter (Power meter) measures the power output of a transmitter. The meter generally has input and
  output connectors and is installed in the feedline between the transmitter and the antenna.
3. SWR Meter:The SWR meter or VSWR (voltage standing wave ratio) meter measures the standing wave ratio in a transmission line...The meter can be used to indicate the degree of mismatch between a transmission line and its load (usually a radio antenna), or evaluate the effectiveness of impedance matching efforts.
4. Grid Dip Meter. (Grid Dip Oscillator - GDO) have been widely used by amateur radio operators for measuring the properties of resonant circuits, filters, and antennas. They can also be used for transmission line testing, as signal generators, and for measuring inductance and capacitance of components.
Electronic T-R switch : Speech processor : S-meter [Information]
1. The T/R (Transmit / Receive) switch must be capable of automatically and rapidly switching the radio antenna or antennas between the transmitter and receiver.
2. The purpose of an RF speech processor is to increase the readability of your signal at the other end of a QSO. Speech processors do not increase peak power; they increase average power output.
3. The S-meter is an instrument present on the majority of radio receivers that measures the strength of the signal that is being received, and uses a special unit: the S-point. S-points are often used for RST reports. S-points go from S1 to S9 and each S-point is defined as a 6 dB change in signal strength.
Dummy Load : Antenna Tuning Unit (ATU) : Oscilloscope [Information]
1. A dummy load is a device used to simulate an electrical load, usually for testing purposes. In radio a dummy antenna is connected to the output of a radio transmitter and electrically simulates an antenna, to allow the transmitter to be adjusted and tested without radiating radio waves.
2. An antenna tuner is a device that is inserted between a radio transmitter and its antenna; when properly adjusted (tuned) it improves power transfer by matching the impedance of the transmitter to the impedance of the antenna.
3. An oscilloscope is an instrument that graphically displays electrical signals and shows how those signals change over time. The primary function of an oscilloscope is to measure voltage waves.
Safety [Information]
1. Before checking a fault in a mains operated power supply unit, first:
  Turn off the power and remove the power plug
2. Wires carrying high voltages in a transmitter should be well insulated to avoid:
  Short circuits
3. A residual current device is recommended for protection in a mains power circuit because it:
  Removes power to the circuit when the phase and neutral currents are not equal
4. An earth wire should be connected to the metal chassis of a mains-operated power supply to ensure that if a fault develops, the chassis:
  Does not develop a high voltage with respect to earth
1. 73 de 4F3EW - 8 November 2021