Harmful interference
EMCAB-2
Splatter interference
Receiver Overload
Inter-modulation
Rectification
Key Clicks
Spurious Emissions
Parasitic oscillation
Harmonic Radiation
Filters
Basic Qualification Question Bank for Amateur Radio Operator Certificate Examinations 12 June, 2014

Interference

Harmful interference

(C)

B-001-010-001 What is a transmission called that disturbs other communications?
A Transponder signals
B Unidentified transmissions
C Harmful interference
D Interrupted CW

(D)
B-001-010-005 What name is given to a form of interference that seriously degrades, obstructs or repeatedly interrupts a radiocommunication service?
A Intentional interference
B Adjacent interference
C Disruptive interference
D Harmful interference

(C)
B-001-010-006 Where interference to the reception of radiocommunications is caused by the operation of an amateur station:
A the amateur station operator may continue to operate without restrictions
B the amateur station operator may continue to operate and the necessary steps can be taken when the amateur operator can afford it
C the Minister may require that the necessary steps for the prevention of the interference be taken by the radio amateur
D the amateur station operator is not obligated to take any action

(D)
B-001-010-007 Radio amateur operation must not cause interference to other radio services operating in which of the following bands?
A 7.0 to 7.1 MHz
B 144.0 to 148.0 MHz
C 14.0 to 14.2 MHz
D 430.0 to 450.0 MHz

(B)
B-001-010-008 Radio amateur operations are not ARE NOT protected from interference caused by another service operating in which of the following frequency bands?
A 50 to 54 MHz
B 902 to 928 MHz
C 144 to 148 MHz
D 222 to 225 MHz

(A)
B-001-010-009 Which of the following is not correct? The operator of an amateur station:
A may make trials or tests, even though there is a possibility of interfering with other stations
B shall not cause harmful interference to a station in another service which has primary use of that band
C may conduct technical experiments using the station apparatus
D may make trials or tests, except if there is a possibility of interference to other stations

(D)
B-001-010-010 Which of these amateur band may be heavily occupied by licence exempt devices?
A 3.5 to 4.0 MHz
B 430 to 450 MHz
C 135.7 to 137.8 kHz
D 902 to 928 MHz

(C)
B-001-010-011 The amateur radio service is authorized to share a portion of what Industrial Scientific Medical(ISM) band that is heavily used by licence exempt devices?
A 144 to 148 MHz
B 1240 to 1300 MHz
C 2300 to 2450 MHz
D 430 to 450 MHz

(D)
B-001-011-010 It is permissible to interfere with the working of another station if:
A the other station is not operating according to the Radiocommunication Regulations
B you both wish to contact the same station
C the other station is interfering with your transmission
D your station is directly involved with a distress situation

(C)
B-001-025-001 In the event of the malfunctioning of a neighbour's broadcast FM receiver and stereo system, it will be deemed that the affected equipment's lack of immunity is the cause if the field strength:
A at the transmitting location is above 100 watts
B near the affected equipment is above Industry Canada's specified immunity criteria
C on the premises of the affected equipment is below Industry Canada's specified immunity criteria
D at the transmitting location is below the radio amateur's maximum allowable transmitter power

(A)
B-001-025-002 In the event of interference to a neighbour's television receiver, according to EMCAB-2 it will be deemed that a radio amateur's transmission is the cause of the problem if the field strength:
A on the neighbour's premises is above Industry Canada's specified immunity criteria
B near the TV is below  Industry Canada's specified immunity criteria
C at the transmitting location is below the radio amateur's maximum allowable transmitter power
D at the transmitting location is above the radio amateur's maximum allowable transmitter power

EMCAB-2

(D)

B-001-025-003 Which of the following is defined in EMCAB-2 as "any device, machinery or equipment, other than radio apparatus, the use or functioning of which is, or can be, adversely affected by radiocommunication emissions"?
A Cable television converters
B Audio and video recorders
C Broadcast receivers
D Radio-sensitive equipment

(A)
B-001-025-004 According to EMCAB-2 which of the following types of equipment is not included in the list of field strength criteria for resolution of immunity complaints?
A Broadcast transmitters
B Broadcast receivers
C Associated equipment
D Radio-sensitive equipment

(A)

B-008-002-001 What devices would you install to reduce or eliminate audio-frequency interference to home entertainment systems?
A Coils on ferrite cores
B Bypass resistors
C Metal-oxide varistors
D Bypass inductors

(D)
B-008-002-002 What should be done if a properly operating amateur station is the cause of interference to a nearby telephone?
A Ground and shield the local telephone distribution amplifier
B Stop transmitting whenever the telephone is in use
C Make internal adjustments to the telephone equipment
D Install a modular plug-in telephone RFI filter close to the telephone device

(D)

B-008-002-008 What device can be used to minimize the effect of RF pickup by audio wires connected to stereo speakers, intercom amplifiers, telephones, etc.?
A Magnet
B Attenuator
C Diode
D Ferrite core

(D)
B-008-002-009 Stereo speaker leads often act as antennas to pick up RF signals. What is one method you can use to minimize this effect?
A Lengthen the leads
B Connect the speaker through an audio attenuator
C Connect a diode across the speaker
D Shorten the leads

(D) One method of preventing RF from entering a stereo set through the speaker leads is to wrap each of the speaker leads:
A around a copper bar
B around an iron bar
C around a wooden dowel
D through a ferrite core

(D)
B-008-002-011 Stereo amplifiers often have long leads which pick up transmitted signals because they act as:
A transmitting antennas
B RF attenuators
C frequency discriminators
D receiving antennas

Splatter interference

(D)

B-003-012-001 What may happen if an SSB transmitter is operated with the microphone gain set too high?
A It may cause interference to other stations operating on a higher frequency band
B It may cause atmospheric interference in the air around the antenna
C It may cause digital interference to computer equipment
D It may cause splatter interference to other stations operating near its frequency

(B)
B-003-012-002 What may happen if an SSB transmitter is operated with too much speech processing?
A It may cause interference to other stations operating on a higher frequency band
B It may cause audio distortion or splatter interference to other stations operating near its frequency
C It may cause digital interference to computer equipment
D It may cause atmospheric interference in the air around the antenna

(A)
B-003-012-007 What happens to the signal of an overmodulated single-sideband or double-sideband phone transmitter?
A It becomes distorted and occupies more bandwidth
B It becomes stronger with no other effects
C It occupies less bandwidth with poor high-frequency response
D It has higher fidelity and improved signal-to-noise ratio

(B)
B-003-012-008 How should the microphone gain control be adjusted on a single-sideband phone transmitter?
A For a dip in plate current
B For slight movement of the ALC meter on modulation peaks
C For full deflection of the ALC meter on modulation peaks
D For 100% frequency deviation on modulation peaks

(B)
B-003-013-001 What may happen if an FM transmitter is operated with the microphone gain or deviation control set too high?
A It may cause interference to other stations operating on a higher frequency band
B It may cause interference to other stations operating near its frequency
C It may cause digital interference to computer equipment
D It may cause atmospheric interference in the air around the antenna

(D)
B-003-013-002 What may your FM hand-held or mobile transceiver do if you shout into its microphone and the deviation adjustment is set too high?
A It may cause digital interference to computer equipment
B It may cause atmospheric interference in the air around the antenna
C It may cause interference to other stations operating on a higher frequency band
D It may cause interference to other stations operating near its frequency

(D)
What can you do if you are told your FM hand-held or mobile transceiver is overdeviating?
A Talk louder into the microphone
B Let the transceiver cool off
C Change to a higher power level
D Talk farther away from the microphone

(C)
B-003-013-010 You are transmitting FM on the 2 metre band. Several stations advise you that your transmission is loud and distorted. A quick check with a frequency counter tells you that the transmitter is on the proper frequency. Which of the following is the most probable cause of the distortion?
A The repeater is reversing your sidebands
B The frequency counter is giving an incorrect reading and you are indeed off frequency
C The frequency deviation of your transmitter is set too high
D The power supply output voltage is low

(B)
B-008-004-006 What causes splatter interference?
A The transmitting antenna is the wrong length
B Overmodulating a transmitter
C Keying a transmitter too fast
D Signals from a transmitter's output circuit are being sent back to its input circuit

Receiver Overload

(A)

B-008-001-001 What is meant by receiver overload?
A Interference caused by strong signals from a nearby transmitter
B Interference caused by turning the volume up too high
C Too much current from the power supply
D Too much voltage from the power supply

(B)
B-008-001-002 What is one way to tell if radio frequency interference to a receiver is caused by front-end overload?
A If connecting a low pass filter to the transmitter greatly cuts down the interference
B If the interference is about the same no matter what frequency is used for the transmitter
C If grounding the receiver makes the problem worse
D If connecting a low pass filter to the receiver greatly cuts down the interference

(A)
B-008-001-003 If a neighbour reports television interference whenever you transmit, no matter what band you use, what is probably the cause of the interference?
A Receiver overload
B Incorrect antenna length
C Receiver VR tube discharge
D Too little transmitter harmonic suppression

(D)
B-008-001-004 What type of filter should be connected to a TV receiver as the first step in trying to prevent RF overload from an amateur HF station transmission?
A Low-pass
B Band-pass
C No filter
D High-pass

(C)
B-008-001-005 During a club ARRL Field Day outing, reception on the 20 m SSB station is compromised every time the 20 m CW station is on the air. What might cause such interference?
A Improper station grounding
B Harmonic radiation
C Receiver desensitization
D Both stations are fed from the same generator

(D)
B-008-001-009 Two mobile stations are traveling along the same road in close proximity to each other and having trouble communicating through a local repeater. Why may it be necessary to use simplex operation to communicate between these cars?
A Simplex operation does not require the use of CTCSS tones
B There is less time delay using simplex operation compared to using a repeater
C There are many more simplex frequencies than repeater frequencies available
D The strong signal of one mobile transmitter may desensitize the receiver of the other mobile receiver

Inter-modulation

(B)

B-008-001-006 Inter-modulation in a broadcast receiver by a nearby transmitter would be noticed in the receiver as:
A interference continuously across the dial
B the undesired signal in the background of the desired signal
C interference only when a broadcast signal is tuned
D distortion on transmitted voice peaks

(B)
B-008-001-007 You have connected your hand-held VHF transceiver to an outside gain antenna. You now hear a mixture of signals together with different modulation on your desired frequency. What is the nature of this interference?
A Audio stage intermodulation interference
B Receiver intermodulation interference
C Harmonic interference from other stations
D Audio stage overload interference

(C)
B-008-001-008 Two or more strong out-of-band signals mix in your receiver to produce interference on a desired frequency. What is this called?
A Capture effect
B Front-end desensitization
C Intermodulation interference
D Receiver quieting

(C)
B-008-001-010 A television receiver suffers interference on channel 5(76 - 82 MHz) only when you transmit on 14 MHz. From your home you see the tower of a commercial FM station known to broadcast on 92.5 MHz. Which of these solutions would you try first?
A Insert a high pass filter at the antenna connector of the HF transmitter
B Insert a low pass filter at the antenna connector of the television
C Insert a high pass filter at the antenna connector of the television
D Insert a low pass filter at the antenna connector of the HF transmitter

(C) How can intermodulation be reduced?
A By increasing the receiver RF gain while decreasing the AF gain
B By adjusting the passband tuning
C By installing a suitable filter at the receiver
D By using a better antenna

Rectification

(D)

B-008-002-003 What sound is heard from a public-address system if audio rectification of a nearby single-sideband phone transmission occurs?
A Clearly audible speech from the transmitter's signals
B On-and-off humming or clicking
C A steady hum whenever the transmitter's carrier is on the air
D Distorted speech from the transmitter's signals

(B)
B-008-002-004 What sound is heard from a public-address system if audio rectification of a nearby CW transmission occurs?
A A steady whistling
B On-and-off humming or clicking
C Audible, possibly distorted speech
D Muffled, severely distorted speech

(D)
B-008-002-005 How can you minimize the possibility of audio rectification of your transmitter's signals?
A Install bypass capacitors on all power supply rectifiers
B Use CW only
C Use a solid-state transmitter
D Ensure that all station equipment is properly grounded

(D)
B-008-002-006 An amateur transmitter is being heard across the entire dial of a broadcast receiver. The receiver is most probably suffering from:
A harmonics interference from the transmitter
B poor image rejection
C splatter from the transmitter
D audio rectification in the receiver

(A)
B-008-002-007 Your SSB HF transmissions are heard muffled on a sound system in the living room regardless of its volume setting. What causes this?
A Audio rectification of strong signals
B Harmonics generated at the transmitter
C Improper filtering in the transmitter
D Lack of receiver sensitivity and selectivity

Key_Clicks

(A)

B-008-003-001 How can you prevent key-clicks?
By using a key-click filter
By increasing power
By using a better power supply
By sending CW more slowly

(D)
B-008-003-005 In Morse code transmission, local RF interference(key-clicks) is produced by:
A frequency shifting caused by poor voltage regulation
B the power amplifier, and is caused by high frequency parasitic oscillations
C poor waveshaping caused by a poor voltage regulator
D the making and breaking of the circuit at the Morse key

(D)
B-008-003-006 Key-clicks, heard from a Morse code transmitter at a distant receiver, are the result of:
A power supply hum modulating the carrier
B sparks emitting RF from the key contacts
C changes in oscillator frequency on keying
D too sharp rise and decay times of the keyed carrier

(B)
B-008-003-007 In a Morse code transmission, broad bandwidth RF interference(key-clicks) heard at a distance is produced by:
A sudden movement in the receiver loudspeaker
B poor shaping of the waveform
C shift in frequency when keying the transmitter
D sparking at the key contacts

(A)
B-008-003-008 What should you do if you learn your transmitter is producing key clicks?
A Check the keying filter and the functioning of later stages
B Turn the receiver down
C Regulate the oscillator supply voltage
D Use a choke in the RF power output

Spurious Emissions

(B)

B-008-003-002 If someone tells you that signals from your hand-held transceiver are interfering with other signals on a frequency near yours, what could be the cause?
A You need to turn the volume up on your hand-held
B Your hand-held is transmitting spurious emissions
C You need a power amplifier for your hand-held
D Your hand-held has a chirp from weak batteries

(C)
B-008-003-003 If your transmitter sends signals outside the band where it is transmitting, what is this called?
A Transmitter chirping
B Off-frequency emissions
C Spurious emissions
D Side tones

(A)
B-008-003-004  What problem may occur if your transmitter is operated without the cover and other shielding in place?
A It may radiate spurious emissions
B It may transmit a weak signal
C It may interfere with other stations operating near its frequency
D It may transmit a chirpy signal

Parasitic oscillation

(C)

B-008-003-009 A parasitic oscillation:
A does not cause any radio interference
B is produced in a transmitter oscillator stage
C is an unwanted signal developed in a transmitter
D is generated by parasitic elements of a Yagi beam

(C)
B-008-003-010 Parasitic oscillations in the RF power amplifier stage of a transmitter may be found:
A at high frequencies only
B at low frequencies only
C at high or low frequencies
D on harmonic frequencies

Harmonic Radiation

(B)

B-008-003-011 Transmitter RF amplifiers can generate parasitic oscillations:
A on harmonics of the transmitter frequency
B above or below the transmitter frequency
C on VHF frequencies only
D on the transmitter fundamental frequency

(A)
B-008-004-001 If a neighbour reports television interference on one or two channels only when you transmit on 15 metres, what is probably the cause of the interference?
A Harmonic radiation from your transmitter
B De ionization of the ionosphere near your neighbour's TV antenna
C TV receiver front-end overload
D Too much low pass filtering on the transmitter

(D)
B-008-004-002 What is meant by harmonic radiation?
A Unwanted signals that are combined with a 60-Hz hum
B Unwanted signals caused by sympathetic vibrations from a nearby transmitter
C Signals which cause skip propagation to occur
D Unwanted signals at frequencies which are multiples of the fundamental(chosen) frequency

(C) Why is harmonic radiation from an amateur station not wanted?
A It may cause sympathetic vibrations in nearby transmitters
B It may cause auroras in the air
C It may cause interference to other stations and may result in out-of-band signals
D It uses large amounts of electric power

(B) What type of interference may come from a multi-band antenna connected to a poorly tuned transmitter?
A Auroral distortion
B Harmonic radiation
C Parasitic excitation
D Intermodulation

(A)
B-008-004-005 If you are told your station was heard on 21 375 kHz, but at the time you were operating on 7125 kHz, what is one reason this could happen?
A Your transmitter was radiating harmonic signals
B Your transmitter's power-supply filter choke was bad
C You were sending CW too fast
D Your transmitter's power-supply filter capacitor was bad

(A)

B-008-004-007 Your amateur radio transmitter appears to be creating interference to the television on channel 3(60-66 MHz) when you are transmitting on the 15 metre band. Other channels are not affected. The most likely cause is:
A harmonic radiation from the transmitter
B no high-pass filter on the TV
C a bad ground at the transmitter
D front-end overload of the TV

(C)
B-008-004-008 One possible cause of TV interference by harmonics from an SSB transmitter is from "flat topping" - driving the power amplifier into non-linear operation. The most appropriate remedy for this is:
A use another antenna
B reduce oscillator output
C reduce microphone gain
D retune transmitter output

(C)
B-008-004-009 In a transmitter, excessive harmonics are produced by:
A resonant circuits
B a linear amplifier
C overdriven stages
D low SWR

(D)
B-008-004-010 An interfering signal from a transmitter is found to have a frequency of 57 MHz(TV Channel 2 is 54 - 60 MHz). This signal could be the:
A crystal oscillator operating on its fundamental
B seventh harmonic of an 80 metre transmission
C third harmonic of a 15 metre transmission
D second harmonic of a 10 metre transmission

(A)
B-008-004-011 Harmonics may be produced in the RF power amplifier of a transmitter if:
A excessive drive signal is applied to it
B the output tank circuit is tuned to the fundamental frequ
ency C the oscillator frequency is unstable
D modulation is applied to a high-level stage

Filters

(D)

B-003-010-007 What kind of filter would you use to attenuate an interfering carrier signal while receiving an SSB transmission?
A A band pass filter
B An all pass filter
C A pi-network filter
D A notch filter

(C)
B-003-010-009 A communications receiver has four filters installed in it, respectively designated as 250 Hz, 500 Hz, 2.4 kHz, and 6 kHz. If you were listening to single sideband, which filter would you utilize?
A 6 kHz
B 500 Hz
C 2.4 kHz
D 250 Hz

(A)
B-003-010-010 A communications receiver has four filters installed in it, respectively designated as 250 Hz, 500 Hz, 2.4 kHz and 6 kHz. You are copying a CW transmission and there is a great deal of interference. Which one of the filters would you choose?
A 250 Hz
B 500 Hz
C 2.4 kHz
D 6 kHz

(A)
B-003-010-011 Selectivity can be placed in the audio stages of a receiver by the utilization of RC active or passive audio filters. If you were to copy CW, which of the following bandpasses would you choose?
A 750 - 850 Hz
B 2100 - 2300 Hz
C 300 - 2700 Hz
D 100 - 1100 Hz

(B)

B-008-005-001 What type of filter might be connected to an amateur HF transmitter to cut down on harmonic radiation?
A A CW filter
B A low pass filter
C A key-click filter
D A high pass filter

(B)
B-008-005-002 Why do modern HF transmitters have a built-in low pass filter in their RF output circuits?
A To reduce RF energy below a cut-off point
B To reduce harmonic radiation
C To reduce fundamental radiation
D To reduce low frequency interference to other amateurs

(A)
B-008-005-003 What circuit blocks RF energy above and below a certain limit?
A A band pass filter
B A high pass filter
C An input filter
D A low pass filter

(D)
B-008-005-004 What should be the impedance of a low pass filter as compared to the impedance of the transmission line into which it is inserted?
A Substantially lower
B Twice the transmission line impedance
C Substantially higher
D About the same

(C)
B-008-005-005 In order to reduce the harmonic output of a high frequency(HF) transmitter, which of the following filters should be installed at the transmitter?
A High pass
B Rejection
C Low pass
D Key click

(D)
B-008-005-006 To reduce harmonic output from a high frequency transmitter, you would put a ____________ in the transmission line as close to the transmitter as possible.
A high pass filter
B band reject filter
C wave trap
D low pass filter

(B)
B-008-005-007  To reduce energy from an HF transmitter getting into a television set, you would place a ____________ as close to the TV as possible.
A band reject filter
B high pass filter
C low pass filter
D wave trap

(A)
B-008-005-008 A band pass filter will:
A allow only certain frequencies through
B attenuate high frequencies but not low
C pass frequencies each side of a band
D stop frequencies in a certain band

(A)
B-008-005-009 A band reject filter will:
A pass frequencies each side of a band
B allow only two frequencies through
C pass frequencies below 100 MHz
D stop frequencies each side of a band

(B)
B-008-005-010 A high pass filter would normally be fitted:
A between transmitter output and transmission line
B at the antenna terminals of the TV receiver
C between microphone and speech amplifier
D at the Morse key or keying relay in a transmitter

(A)
B-008-005-011 A low pass filter suitable for a high frequency transmitter would:
A attenuate frequencies above 30 MHz
B pass audio frequencies above 3 kHz
C attenuate frequencies below 30 MHz
D pass audio frequencies below 3 kHz


The Georgian Bay Amateur Radio Club
P.O. Box 113, Owen Sound
Ontario Canada N4K5P1
© 1973 -2017 GBARC
November 20, 2017