Snap Guys Dancers

reduces the effective plate area
increases the effective plate area
increases the ampere-hour capacity
causes a rise in the specific gravity between 1.22 and 1.27

2. The current at the centre feedpoint of a half wave dipole is:

maximum
minimum
in-phase with the voltage
zero

3. Selective fading of a radio wave results from:

a combination of ground waves and sky waves
bending of line-of-sight waves
wave path variations with small changes in frequency
absorption of the ground wave signal

4. Ionisation in the ionosphere is caused primarily by the:

magnetic effect and axial rotation of the earth
magnetic effect of the sun
ultra-violet and other radiation from the Sun
rotation of the moon

5. Which of the following classes of amplifier would not be suitable for amplification of an SSB emission?

class 'B' grounded grid
class 'A'
class AB
class C

6. The correct detector for FM signals is a:

balanced modulator
discriminator
product detector
infinite-impedance detector

7. Neutralisation of a transmitter power amplifier stage:

improves the Q of the tank circuit
prevents self-oscillation
prevents harmonic radiation
cancels the effect of regeneration from feedback through the anode-cathode capacitance

8. Intermodulation distortion occurs in any non-linear device driven by;

a single high frequency tone
a complex signal having more than one frequency
a single low frequency tone
an unmodulated carrier

9. The velocity factor of a transmission line is:

the relationship between electrical length and physical length
the speed of electron flow within the line
a measure of the efficiency of the line
a measure of its usefulness as a matching stub

10. The impedance of an unterminated transmission line one half wave length long is:

maximum resistive
minimum resistive
maximum inductive
maximum capacitive

11. The bandwidth of an amplitude modulated signal is determined by the:

strength of the modulated signal
frequency of the carrier
frequency of the modulating signal
strength of the carrier

12. A simple S-meter circuit may consist of:

a voltmeter in parallel with the output of the detector
VSWR meter in series with the antenna
milliammeter in series with an RF stage collector current
milliammeter in series with an AF stage base circuit

13. In a frequency modulated wave the power in the carrier:

depends on the number of bessels
remains constant
changes with the degree of modulation
has no power as all the power is in the side frequencies

14. ASCII means:

Australian Semiconductor Interchange Index
American Semiconductor Information Index
Australian Scientific Code for Information Interchange
American Standard Code for Information Interchange

15. What is the most suitable instrument to test whether a transmitter is radiating harmonics?

a deviation meter
an SWR meter
a multimeter with an RF probe
an absorption wave meter

16. The standard colours of the active, neutral and earth conductors respectively in a flexible three core mains power lead are:

red, blue, green
red brown, green
black, brown, green/yellow
brown, blue, green/yellow

17.Terrestial point to point UHF and VHF propagation occurs in the:

ionosphere
stratosphere
troposphere
hemisphere

18. The ripple frequency of a full wave bridge rectifier is:

25 Hertz
100 Hertz
50 Hertz
240 Hertz

19. A folded dipole is used as the driven element in a Yagi antenna:

allows multi-band operation
enables the antenna to be erected in a more confined space
increases the terminal impedance of the antenna
increase the effective height of the antenna

20. The term 'hFE' or 'beta' of a transistor represents the:

noise figure
current amplification factor
operating speed
breakdown voltage

21. An inductor connected in series with an antenna causes an effective:

increase in the antenna length which raises the resonant frequency
decrease in the antenna length which lowers the resonant frequency
increase in the antenna length which lowers the resonant frequency
decrease in the antenna length which raises the resonant frequency

22. A capacitance of 11 nanofarads is the same as:

110 picofarads
1,100 picofarads
11,000 picofarads
11 microfarads

23. Overtone crystal oscillators provide output:

at the fundamental frequency only
on even harmonics
near an odd multiple of the fundamental frequency
on all harmonics

24. A transmitter operating in the 40 metre band is found to be emitting signals on 7100, 7160 and 14,200 respectively. These signals are:

fundamental, parasitic, third harmonic
harmonic, carrier, overtone
fundamental, parasitic, second harmonic
parasitic, overtone, fundamental

25. A heat sink is often used with power transistors to:

increase the forward current
increase the reverse current
isolate the transistor from earth loops in the chassis
prevent excessive temperature rise within the device

26. A Yagi antenna for use in the 144 MHz band would have a:

driven element approximately 2 metres long
director slightly longer than the driven element
reflector slightly longer than the driven element
driven element approximately 2.5 metres long

27. A simple and satisfactory device for producing FM in an amateur transmitter is the:

Foster-Seeley discriminator
ratio detector
varactor reactance modulator
balanced mixer

28. When operating a mobile in a road blasting area the transmitter must not be used because:

others may wish to transmit a warning
charges may be fired by its RF voltage
it may interfere with road work communications
operation from the road side is not allowed in the license conditions

29. Varactor diodes are used for:

supply voltage regulation
altering the effective capacitance of a circuit
limiting the amplitude of oscillation in an oscillator circuit
automatic gain control

30. In amateur satellite communications the apparent shift in frequency caused by the satellite moving toward or away from the Earth is called:

frequency shift
down link effect
Doppler effect
Faraday rotation

31. The three electrodes of a Silicon Controlled Rectifier (SCR) are:

source, emitter and base
anode, cathode and grid
anode, cathode and gate
source, drain and gate

32. A parallel combination of a resistor and a capacitor placed across silicon diodes in high voltage power supplies:

limits the current flow in the power supply
maintains a constant voltage regulation
equalises the PIV drops and guards against transient voltage spikes
increases the heat handling capability of the power supply

33. The RMS value of a sine wave is equal to:

peak x peak
peak / 2
peak x 1.414
peak x 0.707

34. A multiplier for a voltmeter is:

a high resistance in series with the meter movement
a high resistance in parallel with the meter movement
usually less than 1 megohm in series with the meter movement
usually less than 1 megohm in parallel with the meter movement

35. To enable an AM receiver to resolve CW signals, it is necessary to add a:

high gain audio amplifier
narrow band filter before the detector
beat frequency oscillator
more efficient noise limiter

36. Interference to TV reception from harmonics of an FM transmitter will be seen as:

two horizontal bands of white spots
long transversal dashes
ghosting
herringbone weave pattern

37. The impedance of an antenna can be measured with a:

reflectometer
wavemeter
noise bridge
deviation meter

38. Two 5 uF capacitors are connected in series - across the series combination is a 2.5 uF capacitor - the total capacitance is:

2uF
2.5uF
5uF
12.5uF

39. Frequency multipliers are normally operated in:

class A
class B
class AB
class C

40. Spurious interference is generated by a transmitter when the:

transmitter is under-modulated
when the final amplifier stage is neutralised
gain of the RF power amplifier is low
linear power amplifier is overdriven

41. An electret Microphone:

is the same as a dynamic microphone
requires no bias voltage
exhibits a piezoelectric effect
has a high impedance

42. Decreasing the capacitance in a tuned circuit will:

lower the resonant frequency
raise the resonant frequency
not change the resonant frequency
prevent the circuit form being resonant at a higher frequency

43. The calibration of a moving coil meter is linear because the pointer deflection is:

directly proportional to the coil current
inversely proportional to the coil current
directly proportional to the resistance of the coil
inversely proportional to the coil voltage

44. The skip distance is determined by the:

frequency and power level used
frequency used and the state of the ionosphere
effective radiated power and antenna height
power level and the mode of emission used

45. In an RF amplifier parasitic oscillation is caused by:

poor voltage regulation in the power supply
stray circuit inductance and capacitance
a low gain transistor
negative feedback

46. An oscillator will cease operation due to:

loss of DC power to the following stage
increased positive feedback in the oscillator
loss of positive feedback in the oscillator
loss of bias on the following stage

47. Tropospheric ducting may:

cause high frequency signals to fade suddenly
allow long distance VHF communications
occur as a result of meteor showers or auroral activity
occur more frequently on HF than on VHF

48. Eddy currents and hysteresis losses in iron core transformers:

are due to direct current
are not dependent on frequency
increase with frequency
decrease with frequency

49. The term 'vertically polarised electromagnetic wave' refers to a wave in which the:

the vertical electric component has been eliminated
electric component oscillates vertically
magnetic component oscillates vertically
vertical magnetic component has been eliminated

50. The function of the gate in a field effect transistor (FET) is to:

increase or decrease the electron flow to the plate
control but not collect the 'space charge'
stop secondary emission
control the conductance of the channel between source and drain

Score =

Correct answers: