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Amateur Radio Question PoolsNew! View the differences between the 2008 Extra question pool and the previous pool. Canadian Advanced Qualification Question PoolPrev 1 2 3 4 5 6 7 NextA-005-01-01 How is the positive feedback coupled to the input in a Hartley oscillator? Through a capacitive divider Through link coupling Through a neutralizing capacitor A-005-01-02 How is positive feedback coupled to the input in a Colpitts oscillator? Through a neutralizing capacitor Through a link coupling Through a capacitive divider A-005-01-03 How is positive feedback coupled to the input in a Pierce oscillator? Through link coupling Through capacitive coupling Through a tapped coil A-005-01-04 Why is the Colpitts oscillator circuit commonly used in a VFO? It is stable The frequency is a linear function with load impedance It has high output power A-005-01-05 Why must a very stable reference oscillator be used as part of a phaselocked loop (PLL) frequency synthesizer? Any phase variations in the reference oscillator signal will produce phase noise in the synthesizer output Any amplitude variations in the reference oscillator signal will prevent the loop from changing frequency Any amplitude variations in the reference oscillator signal will prevent the loop from locking to the desired signal A-005-01-06 Positive feedback from a capacitive divider indicates the oscillator type is: Hartley Miller Colpitts A-005-01-07 In an oscillator circuit designed for high stability, the positive feedback is drawn from two capacitors connected in series. These two capacitors would most likely be: electrolytics mylar silver mica A-005-01-08 In an oscillator circuit where positive feedback is obtained through a single capacitor in series with the crystal, the type of oscillator is: Hartley Miller Pierce A-005-01-09 A circuit depending on positive feedback for its operation would be a: detector variable-frequency oscillator audio amplifier A-005-01-10 An apparatus with an oscillator and a class C amplifier would be: a fixed-frequency single- sideband transmitter a two-stage frequency- modulated transmitter a two-stage regenerative receiver A-005-01-11 In an oscillator where positive feedback is provided through a capacitor in series with a crystal, that type of oscillator is a: Hartley Franklin Pierce A-005-02-01 The output tuning controls on a transmitter power amplifier: allow efficient transfer of power to the antenna reduce the possibility of crossmodulation in adjunct receivers are involved with frequency multiplication in the previous stage A-005-02-02 The purpose of using a centre-tap return connection on the secondary of transmitting tube's filament transformer is to: reduce the possibility of harmonic emissions keep the output voltage constant with a varying load obtain optimum power output A-005-02-03 In a grounded grid amplifier using a triode vacuum tube, the input signal is applied to: the plate the control grid the filaments A-005-02-04 In a grounded grid amplifier using a triode vacuum tube, the plate is connected to the pi-network through a: tuning capacitor electrolytic capacitor blocking capacitor A-005-02-05 In a grounded grid amplifier using a triode vacuum tube, the plate is connected to a radio frequency choke. The other end of the radio frequency choke connects to the: B+ (high voltage) ground B- (bias) A-005-02-06 In a grounded grid amplifier using a triode vacuum tube, the cathode is connected to a radio frequency choke. The other end of the radio frequency choke connects to the: filament voltage B- (bias) B+ (high voltage) A-005-02-07 In a grounded grid amplifier using a triode vacuum tube, the secondary winding of a transformer is connected directly to the vacuum tube. This transformer provides: B+ (high voltage) Screen voltage filament voltage A-005-02-08 In a grounded grid amplifier using a triode vacuum tube, what would be the approximate B+ voltage required for an output of 400 watts at 400 mA with approximately 50 percent efficiency? 2000 volts 3000 volts 1000 volts A-005-02-09 In a grounded grid amplifier using a triode vacuum tube, each side of the filament is connected to a capacitor whose other end is connected to ground. tuning capacitors by-pass capacitors electrolytic capacitors blocking capacitors A-005-02-10 After you have opened a VHF power amplifier to make internal tuning adjustments, what should you do before you turn the amplifier on? Be certain all amplifier shielding is fastened in place Be certain no antenna is attached so that you will not cause any interference Remove all amplifier shielding to ensure maximum cooling A-005-02-11 Harmonics produced in an early stage of a transmitter may be reduced in a later stage by : greater input to the final stage tuned circuit coupling between stages transistors instead of tubes A-005-03-01 In a simple 2 stage CW transmitter circuit, the oscillator stage and the class C amplifier stage are inductively coupled by a RF transformer. Another role of the RF transformer is to: be part of a tuned circuit provide the necessary feedback for oscillation act as part of a balanced mixer A-005-03-02 In a simple 2 stage CW transmitter, current to the collector of the transistor in the class C amplifier stage flows through a radio frequency choke (RFC) and a tapped inductor. The RFC, on the tapped inductor side, is also connected to grounded capacitors. The purpose of the RFC and capacitors is to: form a low-pass filter form a key-click filter form a RF-tuned circuit A-005-03-03 In a simple 2 stage CW transmitter, the transistor in the second stage would act as: the master oscillator a power amplifier an audio oscillator A-005-03-04 An advantage of keying the buffer stage in a transmitter is that: changes in oscillator frequency are less likely the radiated bandwidth is restricted high RF voltages are not present A-005-03-05 As a power amplifier is tuned, what reading on its grid- current meter indicates the best neutralization? A minimum change in grid current as the output circuit is changed Maximum grid current A maximum change in grid current as the output circuit is changed A-005-03-06 What does a neutralizing circuit do in an RF amplifier? It cancels the effects of positive feedback It reduces incidental grid modulation It controls differential gain A-005-03-07 What is the reason for neutralizing the final amplifier stage of a transmitter? To cut off the final amplifier during standby periods To keep the carrier on frequency To eliminate self-oscillations A-005-03-08 Parasitic oscillations are usually generated due to: excessive drive or excitation to the power amplifier accidental resonant frequencies in the power amplifier a mismatch between power amplifier and feedline A-005-03-09 Parasitic oscillations would tend to occur mostly in: high voltage rectifiers mixer stages RF power output stages A-005-03-10 Why is neutralization necessary for some vacuum-tube amplifiers? To cancel oscillation caused by the effects of interelectrode capacitance To cancel AC hum from the filament transformer To reduce the limits of loaded Q A-005-03-11 Parasitic oscillations in an RF power amplifier may be caused by: unintended tuned circuits lack of neutralisation excessive harmonic production A-005-04-01 What type of signal does a balanced modulator produce? Double sideband, suppressed carrier Full carrier Single sideband, suppressed carrier A-005-04-02 How can a single-sideband phone signal be produced? By using a loop modulator followed by a mixer By using a balanced modulator followed by a filter By using a reactance modulator followed by a mixer A-005-04-03 Carrier suppression in a single-sideband transmitter takes place in: the balanced modulator stage the mechanical filter the frequency multiplier stage A-005-04-04 Transmission with SSB, as compared to conventional AM transmission, results in: 6 dB gain in the transmitter and 3 dB gain in the receiver a greater bandpass requirement in the receiver 3 db gain in the transmitter A-005-04-05 The peak power output of a singlesideband transmitter, when being tested by a two-tone generator is: one-half of the RF peak output power of any of the tones twice the RF power output of any of the tones one-quarter of the RF peak output power of any of the tones A-005-04-06 What kind of input signal is used to test the amplitude linearity of a singlesideband phone transmitter while viewing the output on an oscilloscope? Two audio-frequency sine waves An audio-frequency square wave Normal speech A-005-04-07 When testing the amplitude linearity of a single-sideband microphone input and on what audio tones are fed into the transmitter, what kind of kind of instrument is the output observed? Two harmonically related tones are fed in, and the output is observed on an oscilloscope Two harmonically related tones are fed in, and the output is observed on a distortion analyzer Two non-harmonically related tones are fed in, and the output is observed on a distortion analyzer A-005-04-08 What audio frequencies are used in a two-tone test of the linearity of a singlesideband phone transmitter? 1200 Hz and 2400 Hz tones must be used Any two audio tones may be used, but they must be within the transmitter audio passband, and must be harmonically related Any two audio tones may be used, but they must be within the transmitter audio passband, and should not be harmonically related A-005-04-09 What measurement can be made of a single-sideband phone transmitter's amplifier by performing a two-tone test using an oscilloscope? Its percent of carrier phase shift Its linearity Its percent of frequency modulation A-005-04-10 How much is the carrier suppressed below peak output power in a singlesideband phone transmission? No more than 20 dB No more than 30 dB At least 60 dB A-005-04-11 What is meant by flattopping in a singlesideband phone transmission? Signal distortion caused by insufficient collector current The transmitter's automatic level control is properly adjusted The transmitter's carrier is properly suppressed A-005-05-01 In an FM phone signal having a maximum frequency deviation of 3000 Hz either side of the carrier frequency, what is the modulation index, when the modulating frequency is 1000 Hz? 0.3 3000 1000 A-005-05-02 What is the modulation index of an FM phone transmitter producing an instantaneous carrier deviation of 6 kHz when modulated with a 2 kHz modulating frequency? 2000 3 6000 A-005-05-03 What is the deviation ratio of an FM phone signal having a maximum frequency swing of plus or minus 5 kHz and accepting a maximum modulation rate of 3 kHz? 0.16 0.6 1.66 A-005-05-04 What is the deviation ratio of an FM phone signal having a maximum frequency swing of plus or minus 7.5 kHz and accepting a maximum modulation rate of 3.5 kHz? 2.14 47 0.214 A-005-05-05 When the transmitter is not modulated, or the amplitude of the modulating signal is zero, the frequency of the carrier is called its: frequency shift modulating frequency centre frequency A-005-05-06 In a FM transmitter system, the number of cycles of deviation from the centre frequency is determined solely by the: frequency of the modulating frequency amplitude and the frequency of the modulating frequency modulating frequency and the amplitude of the centre frequency A-005-05-07 Any FM wave with single-tone modulation has: four sideband frequencies one sideband frequency an infinite number of sideband frequencies A-005-05-08 The deviation meter works on the principle of: the amplitude of power in the sidebands a carrier null and multiplying the modulation frequency by the modulation index a carrier peak and dividing by the modulation index A-005-05-09 When using a deviation meter, it is important to know: modulation index modulating frequency pass-band of the IF filter A-005-05-10 What is the total bandwidth of an FMphone transmission having a 5-kHz deviation and a 3-kHz modulating frequency? 5 kHz 16 kHz 3 kHz A-005-05-11 What is the frequency deviation for a 12.21-MHz reactance-modulated oscillator in a 5-kHz deviation, 146.52- MHz FM-phone transmitter? 5 kHz 416.7 Hz 41.67 Hz A-005-06-01 If the signals of two repeater transmitters mix together in one or both of their final amplifiers and unwanted signals at the sum and difference frequencies of the original signals are generated, what is this called? Intermodulation interference Adjacent channel interference Amplifier desensitization A-005-06-02 How does intermodulation interference between two repeater transmitters usually occur? When they are in close proximity and the signals cause feedback in one or both of their final amplifiers When they are in close proximity and the signals mix in one or both of their final amplifiers When the signals are reflected out of phase by aircraft passing overhead A-005-06-03 How can intermodulation interference between two repeater transmitters in close proximity often be reduced or eliminated? By installing a high-pass filter in the antenna feed line By installing a terminated circulator or ferrite isolator in the feed line to the transmitter and duplexer By using a Class C final amplifier with high driving power A-005-06-04 If a receiver tuned to 146.70 MHz receives an intermodulation product signal whenever a nearby transmitter transmits on 146.52, what are the two most likely frequencies for the other interfering signal? 146.01 MHz and 147.30 MHz 73.35 MHz and 239.40 MHz 146.34 MHz and 146.61 MHz A-005-06-05 What type of circuit varies the tuning of an amplifier tank circuit to produce FM signals? A balanced modulator A double balanced mixer An audio modulator A-005-06-06 What audio shaping network is added at an FM transmitter to attenuate the lower audio frequencies? A heterodyne suppressor A pre-emphasis network A de-emphasis network A-005-06-07 Which type of filter would be best to use in a 2-metre repeater duplexer? A cavity filter An L-C filter A crystal filter A-005-06-08 The characteristic difference between a phase modulator and a frequency modulator is: the centre frequency de-emphasis frequency inversion A-005-06-09 In most modern FM transmitters, to produce a better sound, a compressor and a clipper are placed: between the modulator and the oscillator in the microphone circuit, before the audio amplifier between the audio amplifier and the modulator A-005-06-10 Three important parameters to be verified in an FM transmitter are: distortion, bandwidth and sideband power modulation, pre-emphasis and carrier suppression frequency stability, de-emphasis and linearity A-005-06-11 For a repeater to operate automatically, the circuit that determines when to turn the transmitter on and off is the: carrier operated relay automatic identifier multiplier A-005-07-01 Maintaining the peak RF output of a SSB transmitter at a relatively constant level requires a circuit called the: automatic gain control (AGC) automatic output control (AOC) automatic volume control (AVC) A-005-07-02 Speech compression associated with SSB transmission implies: full amplification of high level signals and reducing or eliminating signals amplification of low level a lower signal-to-noise ratio circuit level instability A-005-07-03 Which of the following functions IS NOT included in a typical digital signal processor? Analog to digital converter Digital to analog converter Mathematical transform A-005-07-04 How many bits are required to provide 256 discrete levels, or a ratio of 256:1? 16 bits 8 bits 4 bits A-005-07-05 Adding one bit to the word length, is equivalent to adding ____ dB to the dynamic range of the digitizer: 4 dB 6 dB 3 dB A-005-07-06 What do you call the circuit which employs an analog to digital converter, a mathematical transform, a digital to analog converter and a low pass filter? Mathematical transformer Digital signal processor Digital transformer A-005-07-07 Which principle IS NOT associated with analog signal processing? frequency division bandwidth limiting clipping A-005-07-08 Which of the following IS NOT a method used for peak limiting, in a signal processor? frequency clipping compression AF clipping A-005-07-09 What is the undesirable result of AF clipping in a speech processor? Increased average power Increased harmonic distortion Reduction in peak amplitude A-005-07-10 Which description IS NOT correct? You are planning to build a speech processor for your transceiver. Compared to AF clipping, RF clipping: is more expensive to implement is more difficult to implement is easier to implement A-005-07-11 Automatic Level Control (ALC) is another name for: AF compression RF clipping AF clipping A-005-08-01 What digital code consists of elements having unequal length? Baudot Morse code ASCII A-005-08-02 The International Organization for Standardization has developed a sevenlevel reference model for a packet-radio communications structure. What level is responsible for the actual transmission of data and handshaking signals? The physical layer The network layer The transport layer A-005-08-03 The International Organization for Standardization has developed a sevenlayer reference model for a packet-radio communications structure. What level arranges the bits into frames and controls data flow? The synchronization layer The communications layer The transport layer A-005-08-04 What is one advantage of using ASCII rather than Baudot code? ASCII includes built-in error correction ASCII characters contain fewer information bits The larger character set allows storeand- forward A-005-08-05 What type of error control system is used in AMTOR ARQ (Mode A)? Each character is sent twice The receiving station automatically requests repeats when needed Mode A AMTOR does not include an error control system A-005-08-06 What error-correction system is used in AMTOR FEC (Mode B)? The receiving station automatically requests repeats when needed The receiving station checks the frame check sequence (FCS) against the transmitted FCS Each character is sent twice A-005-08-07 What is the primary advantage of AMTOR over Baudot RTTY? AMTOR includes an error detection system Photographs may be transmitted using AMTOR AMTOR characters contain fewer information bits than Baudot characters A-005-08-08 We have all used the term ASCII when using computers or teletypewriting equipment. What do those initials represent? American Standard Code for Information Interchange North American System Compatible with International Interchange Amalgamated System Code for Information Interchange A-005-08-09 The designator AX.25 is associated with which amateur radio mode? RTTY ASCII spread spectrum speech A-005-08-10 How many information bits are included in the Baudot code? 5 8 6 A-005-08-11 How many information bits are included in the ASCII code? 7 6 5 A-005-09-01 What term describes a wide-band communications system in which the RF carrier varies according to some predetermined sequence? Amplitude-compandored single sideband AMTOR Time domain frequency modulation A-005-09-02 What is the term used to describe a spread spectrum communications system where the centre frequency of a conventional carrier is altered many times per second in accordance with a pseudo- random list of channels? Time-domain frequency modulation Frequency compandored spread spectrum Frequency hopping A-005-09-03 What term is used to describe a spread spectrum communications system in which a very fast binary bit stream is used to shift the phase of an RF carrier? Phase compandored spread spectrum Direct sequence Binary phase-shift keying A-005-09-04 Frequency hopping is used with which type of transmission? AMTOR Packet RTTY A-005-09-05 Direct sequence is used with which type of transmission? AMTOR Packet RTTY A-005-09-06 Which type of signal is used to produce a predetermined alteration in the carrier for spread spectrum communication? Quantizing noise Pseudo-random sequence Random noise sequence A-005-09-07 Why is it difficult to monitor a spread spectrum transmission? It varies too quickly in amplitude The signal is too distorted for comfortable listening Your receiver must be frequencysynchronized to the transmitter A-005-09-08 What is frequency hopping spread spectrum? The carrier is frequency-compandored The carrier is altered in accordance with a pseudo-random list of channels The carrier is phase-shifted by a fast binary bit stream A-005-09-09 What is direct-sequence spread spectrum? The carrier is frequency-compandored The carrier is phase-shifted by a fast binary bit stream The carrier is altered in accordance with a pseudo-random list of channels A-005-09-10 Why are received spread-spectrum signals so resistant to interference? Signals not using the spectrum-spreading algorithm are suppressed in the receiver If interference is detected by the receiver, it will signal the transmitter to change frequencies The high power used by a spreadspectrum transmitter keeps its signal from being easily overpowered A-005-09-11 How does the spread-spectrum technique of frequency hopping (FH) work? If interference is detected by the receiver, it will signal the transmitter to change frequency If interference is detected by the receiver, it will signal the transmitter to wait until the frequency is clear A pseudo-random bit stream is used to shift the phase of an RF carrier very rapidly in a particular sequence |
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