NavigationUser loginWho's new
|
Amateur Radio Question PoolsNew! View the differences between the 2008 Extra question pool and the previous pool. Canadian Basic Qualification Question PoolPrev 1 2 3 4 5 6 7 8 NextB-008-01-01 What is meant by receiver overload? Interference caused by turning the volume up too high Too much current from the power supply Interference caused by strong signals from a nearby transmitter Too much voltage from the power supply B-008-01-02 What is one way to tell if radio frequency interference to a receiver is caused by front-end overload? If grounding the receiver makes the problem worse If connecting a low pass filter to the receiver greatly cuts down the interference If the interference is about the same no matter what frequency is used for the transmitter If connecting a low pass filter to the transmitter greatly cuts down the interference B-008-01-03 If a neighbour reports television interference whenever you transmit, no matter what band you use, what is probably the cause of the interference? Incorrect antenna length Receiver VR tube discharge Receiver overload Too little transmitter harmonic suppression B-008-01-04 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? High-pass Low-pass Band-pass No filter B-008-01-05 When the signal from a transmitter overloads the audio stages of a broadcast receiver, the transmitted signal: is distorted on voice peaks can appear wherever the receiver is tuned appears only on one frequency appears only when a station is tuned B-008-01-06 Cross-modulation of a broadcast receiver by a nearby transmitter would be noticed in the receiver as: interference only when a broadcast signal is tuned the undesired signal in the background of the desired signal distortion on transmitted voice peaks interference continuously across the dial B-008-01-07 What is cross-modulation interference? Interference between two transmitters of different modulation type Interference caused by audio rectification in the receiver reamplifier Harmonic distortion of the transmitted signal Modulation from an unwanted signal is heard in addition to the desired signal B-008-01-08 What is the term used to refer to the condition where the signals from a very strong station are superimposed on other signals being received? Receiver quieting Cross-modulation interference Capture effect Intermodulation distortion B-008-01-09 What is the result of cross-modulation? Receiver quieting A decrease in modulation level of transmitted signals Inverted sidebands in the final stage of the amplifier The modulation of an unwanted signal is heard on the desired signal B-008-01-10 If a television receiver suffers from cross-modulation when a nearby amateur transmitter is operating at 14 MHz, which of the following cures might be effective? A low pass filter attached to the antenna output of the transmitter A high pass filter attached to the antenna output of the transmitter A high pass filter attached to the antenna input of the television A low pass filter attached to the antenna input of the television B-008-01-11 How can cross-modulation be reduced? By installing a suitable filter at the receiver By using a better antenna By increasing the receiver RF gain while decreasing the AF gain By adjusting the passband tuning B-008-02-01 What devices would you install to reduce or eliminate audio-frequency interference to home entertainment systems? Bypass resistors Metal-oxide varistors Bypass capacitors Bypass inductors B-008-02-02 What should be done if a properly operating amateur station is the cause of interference to a nearby telephone? Ground and shield the local telephone distribution amplifier Stop transmitting whenever the telephone is in use Ask the telephone company to install RFI filters Make internal adjustments to the telephone equipment B-008-02-03 What sound is heard from a public-address system if audio rectification of a nearby single-sideband phone transmission occurs? Clearly audible speech from the transmitter's signals On-and-off humming or clicking Distorted speech from the transmitter's signals A steady hum whenever the transmitter's carrier is on the air B-008-02-04 What sound is heard from a public-address system if audio rectification of a nearby CW transmission occurs? Audible, possibly distorted speech Muffled, severely distorted speech A steady whistling On-and-off humming or clicking B-008-02-05 How can you minimize the possibility of audio rectification of your transmitter's signals? By installing bypass capacitors on all power supply rectifiers By using CW emission only By ensuring that all station equipment is properly grounded By using a solid-state transmitter B-008-02-06 An amateur transmitter is being heard across the entire dial of a broadcast receiver. The receiver is most probably suffering from: harmonics interference from the transmitter cross-modulation or audio rectification in the receiver poor image rejection splatter from the transmitter B-008-02-07 Cross-modulation is usually caused by: rectification of strong signals harmonics generated at the transmitter improper filtering in the transmitter lack of receiver sensitivity and selectivity B-008-02-08 What device can be used to minimize the effect of RF pickup by audio wires connected to stereo speakers, intercom amplifiers, telephones, etc.? Magnet Attenuator Diode Ferrite core B-008-02-09 Stereo speaker leads often act as antennas to pick up RF signals. What is one method you can use to minimize this effect? Shorten the leads Lengthen the leads Connect the speaker through an audio attenuator Connect a diode across the speaker B-008-02-10 One method of preventing RF from entering a stereo set through the speaker leads is to wrap each of the speaker leads around a: copper bar iron bar ferrite core wooden dowel B-008-02-11 Stereo amplifiers often have long leads which pick up transmitted signals because they act as: transmitting antennas RF attenuators frequency discriminators receiving antennas B-008-03-01 How can you prevent key-clicks? By increasing power By using a key-click filter By using a better power supply By sending CW more slowly B-008-03-02 If someone tells you that signals from your hand-held transceiver are interfering with other signals on a frequency near yours, what may be the cause? Your hand-held may be transmitting spurious emissions You may need a power amplifier for your hand-held Your hand-held may have chirp from weak batteries You may need to turn the volume up on your hand-held B-008-03-03 If your transmitter sends signals outside the band where it is transmitting, what is this called? Side tones Transmitter chirping Spurious emissions Off-frequency emissions B-008-03-04 What problem may occur if your transmitter is operated without the cover and other shielding in place? It may transmit a weak signal It may transmit spurious emissions It may interfere with other stations operating near its frequency It may transmit a chirpy signal B-008-03-05 In Morse code transmission, local RF interference (key-clicks) is produced by: the making and breaking of the circuit at the Morse key frequency shifting caused by poor voltage regulation the power amplifier, and is caused by high frequency parasitics poor waveshaping caused by a poor voltage regulator B-008-03-06 Key-clicks, heard from a Morse code transmitter at a distant receiver, are the result of: power supply hum modulating the carrier too sharp rise and decay times of the carrier sparks emitting RF from the key contacts changes in oscillator frequency on keying B-008-03-07 In a Morse code transmission, local RF interference (key-clicks) is produced by: shift in frequency when keying the transmitter sparking at the key contacts sudden movement in the receiver loudspeaker poor shaping of the waveform B-008-03-08 Key-clicks can be suppressed by: inserting a choke and a capacitor at the key turning the receiver down regulating the oscillator supply voltage using a choke in the RF power output B-008-03-09 A parasitic oscillation: is generated by parasitic elements of a Yagi beam does not cause any radio interference is produced in a transmitter oscillator stage is an unwanted signal developed in a transmitter B-008-03-10 Parasitic oscillations in the RF power amplifier stage of a transmitter may be found: at high or low frequencies on harmonic frequencies at high frequencies only at low frequencies only B-008-03-11 Transmitter RF amplifiers can generate parasitic oscillations: on VHF frequencies only on the transmitter fundamental frequency on either side of the transmitter frequency on harmonics of the transmitter frequency B-008-04-01 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? De ionization of the ionosphere near your neighbour's TV antenna Harmonic radiation from your transmitter TV receiver front-end overload Too much low pass filtering on the transmitter B-008-04-02 What is meant by harmonic radiation? Unwanted signals at frequencies which are multiples of the fundamental (chosen) frequency Unwanted signals that are combined with a 60-Hz hum Unwanted signals caused by sympathetic vibrations from a nearby transmitter Signals which cause skip propagation to occur B-008-04-03 Why is harmonic radiation from an amateur station not wanted? It uses large amounts of electric power It may cause sympathetic vibrations in nearby transmitters It may cause auroras in the air It may cause interference to other stations and may result in out-of-band signals B-008-04-04 What type of interference may come from a multi-band antenna connected to a poorly tuned transmitter? Parasitic excitation Harmonic radiation Intermodulation Auroral distortion B-008-04-05 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? Your transmitter's power-supply filter choke was bad You were sending CW too fast Your transmitter was radiating harmonic signals Your transmitter's power-supply filter capacitor was bad B-008-04-06 What causes splatter interference? Keying a transmitter too fast Signals from a transmitter's output circuit are being sent back to its input circuit The transmitting antenna is the wrong length Overmodulation of a transmitter B-008-04-07 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: no high-pass filter on the TV a bad ground at the transmitter harmonic radiation from the transmitter front-end overload of the TV B-008-04-08 One possible cause of TV interference by harmonics from an SSB transmitter is from "flat topping" - driving the final amplifier into non- linear operation. The most appropriate remedy for this is: retune transmitter output use another antenna reduce microphone gain reduce oscillator output B-008-04-09 In a transmitter, excessive harmonics are produced by: low SWR resonant circuits a linear amplifier overdriven stages B-008-04-10 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: crystal oscillator operating on its fundamental seventh harmonic of an 80 metre transmission second harmonic of a 10 metre transmission third harmonic of a 15 metre transmission B-008-04-11 Harmonics may be produced in the RF power amplifier of a transmitter if: excessive drive signal is applied to it the output tank circuit is not correctly tuned the oscillator frequency is unstable modulation is applied to more than one stage B-008-05-01 What type of filter might be connected to an amateur HF transmitter to cut down on harmonic radiation? A low pass filter A key-click filter A high pass filter A CW filter B-008-05-02 Why do modern HF transmitters have a built-in low pass filter in their RF output circuits? To reduce fundamental radiation To reduce low frequency interference to other amateurs To reduce harmonic radiation To reduce RF energy below a cut-off point B-008-05-03 What circuit blocks RF energy above and below a certain limit? A high pass filter An input filter A low pass filter A band pass filter B-008-05-04 What should be the impedance of a low pass filter as compared to the impedance of the transmission line into which it is inserted? Substantially lower Twice the transmission line impedance About the same Substantially higher B-008-05-05 In order to reduce the harmonic output of a high frequency (HF) transmitter, which of the following filters should be installed at the transmitter? Band pass High pass Rejection Low pass B-008-05-06 To reduce harmonic output from a transmitter, you would put a ____________ in the transmission line as close to the transmitter as possible. high pass filter low pass filter band reject filter wave trap B-008-05-07 To reduce energy from an HF transmitter getting into a television set, you would place a ____________ as close to the TV as possible. low pass filter wave trap band reject filter high pass filter B-008-05-08 A band pass filter will: attenuate high frequencies but not low pass frequencies each side of a band allow only certain frequencies through stop frequencies in a certain band B-008-05-09 A band reject filter will: allow only two frequencies through pass frequencies each side of a band pass frequencies below 100 MHz stop frequencies each side of a band B-008-05-10 A high pass filter would normally be fitted: between microphone and speech amplifier at the Morse key or keying relay in a transmitter at the antenna terminals of the TV receiver between transmitter output and feed line B-008-05-11 A low pass filter suitable for a high frequency transmitter would: pass audio frequencies above 3 kHz attenuate frequencies below 30 MHz attenuate frequencies above 30 MHz pass audio frequencies below 3 kHz |
ARRL Amateur Radio News |
