Standard theory trial exam

  1. The distance from a transmitter to the point where the signal first returns after refraction from the ionosphere is called
    a) multi hop
    b) skip zone
    c) skip distance
    d) ionosphere prediction distance

  2. To prevent radiation of radio frequency signals when a transmitter is being tested continuously, you should use
    a) a transmission line
    b) an artificial antenna
    c) an indoor antenna
    d) a standing wave ratio (SWR) meter

  3. A correctly operated Standard transmitter causes severe interference to one television set in close proximity but not to others in the same location. The problem is probably due to
    a) harmonic radiation
    b) front-end overload of the television set
    c) cross-modulation with an "off air" broadcast transmitter
    d) radiation of parasitics

  4. The approximate length of a half wave dipole antenna for 21 MHz is
    a) 15 metres
    b) 0.75 metres
    c) 7.5 metres
    d) 2.5 metres

  5. What can occur when a single-sideband signal is amplified by a nonlinear amplifier?
    a) lower amplifier efficiency
    b) increased readability
    c) elimination of unwanted sideband
    d) distortion

  6. What does the term "receiver overload" mean?
    a) Interference caused by overcrowding of the band
    b) Interference caused by a strong signal from a nearby transmitter
    c) Interference caused by adjusting the receiver volume too high
    d) Interference caused by transmitter harmonics

  7. Ionization in the ionosphere is caused primarily by the
    a) magnetic effect and axial rotation of the earth
    b) magnetic effect of the sun
    c) ultraviolet and other radiation from the sun
    d) rotation of the moon

  8. The function of a tripler stage in a transmitter is to
    a) multiply the frequency of the incoming signal by three
    b) triple the power output
    c) enable two final stages to be fed by the one oscillator
    d) act as an impedance doubling device

  9. The input impedance of a Field Effect Transistor (FET) is
    a) very high
    b) very low
    c) current dependant
    d) voltage dependant

  10. The ratio of the collector current Ic to the base current Ib of a transistor is called
    a) resistance gain
    b) voltage gain
    c) power gain
    d) current gain

  11. The feed impedance of a centre fed half wave dipole is free space is
    a) 300 ohms
    b) 50 ohms
    c) 72 ohms
    d) 32 ohms

  12. The standing wave ratio (SWR) on a transmission line is related to the
    a) voltage at the ends of the antenna and the voltage at the feed point
    b) maximum voltage and the maximum current in the antenna
    c) power fed to the antenna and the power reflected back from the antenna
    d) maximum voltage and the maximum current in the transmission line

    13

  13. This diagram shows the circuit of
    a) a full wave rectifier
    b) a half wave rectifier
    c) an oscillator
    d) a detector

  14. The ability of a communications receiver to distinguish between signals that are close in frequency is known as its
    a) selectivity
    b) sensitivity
    c) stability
    d) bandspread

    15

  15. The zener doide in this diagram
    a) is reversed biased
    b) is forward biased
    c) has positive voltage applied to its anode
    d) is not conducting

  16. Operation of the Receiver Increment Tuning (clarifier) control in a SSB transceiver
    a) increases the selectivity of the receiver
    b) adjusts the receiver gain in small steps
    c) varies the sensitivity of the receiver
    d) provides a small variation of receiver tuning

  17. Which of the following will increase the inductance of a coil
    a) increasing the coil diameter
    b) increasing the spacing between turns
    c) decreasing the number of turns
    d) all of the above

  18. If a transmitter drifts in its output frequency this would likely be due to
    a) parasitic oscillations
    b) harmonic radiation
    c) instability
    d) power supply variations

  19. A radiofrequency bypass capacitor
    a) blocks radio frequencies and passes direct current
    b) blocks direct current and passes radio frequencies
    c) must have a high reactance in order to be effective
    d) provides a low inpedance path for direct current

  20. Long distance high-frequency communication at night is normally via the ionospheric
    a) D layer
    b) F layer
    c) E layer
    d) N layer

  21. One kHz is the same as
    a) 10 Hz
    b) 100Hz
    c) 1,000 Hz
    d) 10,000 Hz

  22. When compared to ground wave propagation sky wave propagation usually has
    a) Much smaller effective range
    b) Much greater effective range
    c) The same effective range
    d) Differing effective range depending of the weather

  23. To extend the range of an ammeter it is necessary to use a
    a) resistor in series with the meter
    b) resistor in parallel with the meter
    c) rectifier in series with the meter
    d) capacitor in parallel with the meter

  24. An interfering signal from a Standard transmitter appears on 56.6 MHz. This could be due to the
    a) crystal oscillator operating on its fundamental frequency
    b) second harmonic of a 10 metre transmission
    c) third harmonic of a 15 metre transmission
    d) seventh harmonic of an 80 metre transmission

  25. The main reason for earthing mains powered equipment is to
    a) reduce RF interference
    b) reduce eddy currents
    c) reduce shock hazards
    d) reduce stray coupling

    26

  26. This carbon filament resistor may be described as
    a) 220K ohms 5%
    b) 22K ohms 5%
    c) 220K ohms 10%
    d) 56 ohms 5%

  27. The reactance of an inductor
    a) increases as the applied frequency rises
    b) decreases as the applied frequency rises
    c) decreases as the inductance rises
    d) is proportional to the current flow

  28. To convert alternating current to direct current, use is made of a
    a) thermistor
    b) resonant circuit
    c) diode
    d) carbon resistor

  29. A receiver which cannot pick up weak signals is lacking in
    a) sensitivity
    b) selectivity
    c) modulation
    d) stability

  30. What type of modulation system changes the amplitude of an
    RF wave for the purpose of conveying information?
    a) frequency modulation
    b) phase modulation
    c) amplitude-rectification modulation
    d) amplitude modulation

  31. Bleeder resistors are included in power supplies to
    a) discharge filter capacitors after the supply voltage is switched off
    b) prevent damage to filter during overload
    c) reduce ripple in the output voltage
    d) reduce the size of the filter choke

  32. Which of the following is a type of electrolytic capacitor?
    a) plastic
    b) mica
    c) tantalum
    d) ceramic

  33. The amount of forward bias required to enable a germanium transistor to commence conduction is approximately
    a) 0.2 volt
    b) 0.6 volt
    c) 0.9 volt
    d)1.0 volt

  34. Four 10 ohm resistors are connected in series. The total resistance is
    a) 2.5 ohms
    b) 4 ohms
    c) 10 ohms
    d) 40 ohms

  35. The opposition to current flow in a purely inductive or capacitive circuit is its
    a) resistance
    b) reluctance
    c) resonance
    d) reactance

  36. In fitting an amateur transceiver to a motor vehicle an important matter to consider is?
    a) whether there is voltage available to power the transceiver
    b) the placement of a laptop computer for logging purposes
    c) potential interference to the engine management system
    d) signal reflections from the wing mirrors

  37. When a current of 10 millamperes flows through a resistance of 10 ohms, the voltage drop across the resistor is
    a) 10 millivolts
    b) 100 millivolts
    c) 1 volt
    d) 10 volts

  38. The RF amplifier stages in television sets are designed to receive signals in which of the following frequency ranges
    a) 50-225 MHz and 470-854 MHz
    b) 30-150 MHz and 800-1300 MHz
    c) 70 MHz - 900 MHz
    d) 44 MHz - 900 MHz

  39. Crystal oscillators are often used for frequency control in receivers because they
    a) have more output than other oscillators
    b) are more stable than L-C oscillators
    c) radiate fewer harmonics than other oscillators
    d) generate more harmonics than other oscillators

  40. The purpose of the AGC in a superheterodyne receiver is to
    a) maintain a constant current drain from the power supply
    b) maintain a constant output level with wide input variations
    c) provide a small variation in receiver tuning
    d) keep the local oscillator frequency constant

  41. The active conductor in a 3-core AC power cords is coloured
    a) brown
    b) yellow/green
    c) red
    d) blue

  42. The total resistance of four 68 ohm resistors in parallel is
    a) 272 ohms
    b) 12 ohms
    c) 17 ohms
    d) 34 ohms

    43

  43. The mode of operation of this amplifier is known as a
    a) common emitter
    b) common collector
    c) common drain
    d) common gate

  44. The mixing of audio and radio frequency signals is
    a) frequency multiplication
    b) frequency mixing
    c) detection
    d) modulation

  45. The term "hFE" or "beta" of a transistor is its
    a) noise figure
    b) current amplification factor
    c) operating speed
    d) breakdown voltage

  46. The frequency of the local oscillator is
    a) 910 kHz
    b) 3625 kHz
    c) 4080 kHz
    d) 4990 kHz


  47. The RMS value of a sine wave can be calculated by
    a) peak x 2
    b) peak รท 2
    c) peak x 0.707
    d) peak x 1.414

    48

  48. This circuit diagram shows
    a) resistor and capacitor in parallel
    b) resistor and capacitor in series
    c) resistor and inductor in series
    d) capacitor and inductor in parallel

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  49. The basic filter characteristic drawn below, represents that of a
    a) low pass
    b) high pass
    c) bandpass
    d) bandstop

  50. Voltage variable capacitor (varicap or varactor) diodes behave as capacitors when
    a) biased in the forward direction
    b) un-biased
    c) saturated
    d) biased in the reverse direction

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