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CHAPTER 5
1 If the frequency stability of a transmitter is poor it may
cause:
a. Electric shocks.
b.* Operation out of the bands.
c. Excessive collector dissipation.
d. Excessive power to be drawn from the supply.
2 The frequency stability of a VFO is dependant upon:
a.* Temperature compensated components.
b. The use of large components.
c. Soldered connections.
d. Adjustable power supplies.
3 The frequency stability of mobile equipment is dependant upon
a. Mobile battery voltage.
b. Speed at which the vehicle travels.
c.* Wide temperature ranges that occur in a vehicle.
d. The type of antenna used.
4 If the coil in a VFO has no former, then vibrations:
a. Will keep the frequency generated in the band.
b.* May take the frequency generated out of the band.
c. Will provide a clean signal.
d. Are beneficial.
5 To prevent the operating frequency of a mobile transceiver
varying while a vehicle is traveling:
a. The mobile antenna must be matched.
b. The power lead must be filtered.
c.* The oscillator coils should be unable to vibrate.
d. The voltage supply should not exceed 12 Volt.
6 Rigid mechanical construction of a VFO is desirable to minimize
a.* Short term frequency instability.
b. Long term frequency drift.
c. Oscillator chirp when keyed.
d. Thermal frequency drift.
7 If an LC oscillator is used to generate directly a signal at
14,05Mhz for a CW transmitter and it drifts by -1%, it will:
a. Stay within the designated band.
b. Go above the top band edge.
c.* Go below the bottom band edge.
d. Be rejected.
8 If a 14,10 MHz oscillator drifts by +1% then the frequency will
be:
a. 14,20MHz.
b.* 14,241MHz.
c. 14,11MHz.
d. Equal to crystal control.
9 The 100pf capacitor in a resonant circuit decreases in
capacitance by 10% when it gets hot. The effect it will have on a
7.3Mhz oscillator will be:
a. To increase the harmonic output of the oscillator.
b. To decrease the oscillation frequency.
c.* Allow the oscillation frequency to drift out of the 7MHz band.
d. To stop oscillation as the circuit is no longer resonant.
10 Chirp is a form of frequency instability. It is caused by:
a. Background noise.
b. Over modulation.
c. Over deviation.
d.* Pulling of an oscillator when keying.
11 Chirp on a CW signal can be minimized by:
a.* Providing a stable power supply to the oscillator.
b. Keeping the key down while receiving.
c. Using thicker wires.
d. Using a paddle.
12 Which of the following actions would NOT help to achieve a
reduction of "chirp" in a VFO-controlled Morse code transmitter?
a. Adding voltage regulation to the oscillator power supply.
b. Using a buffer stage after the oscillator.
c.* Running the transmitter output at the same frequency as the
oscillator.
d. Key a later stage in the transmitter rather than the
oscillator.
13 To stop unwanted radiations from an oscillator, it should be:
a.* enclosed in a metal box.
b. left unscreened.
c. not be RF decoupled.
d. placed in a paper box.
14 Power supplies to RF Power amplifiers should:
a. be open wires.
b. be AF filtered.
c.* be RF filtered.
d. be inductively coupled.
15 It is good practice to feed DC power to screened oscillators
and mixers using:
a. A reverse polarity diode.
b.* A feed through capacitor in the line.
c. A printed circuit board.
d. An isolation transformer.
16 A wide bandwidth signal must not:
a.* Generate signals outside the allocated bands.
b. Exceed 75% modulation.
c. Be used on any amateur bands.
d. Be used for test purposes.
17 Which of the following modes of amateur transmission uses the
narrowest band of frequency?
a.* Interrupted continuous wave.
b. Audio frequency shift keying.
c. Fast scan television.
d. Single sideband suppressed carrier.
18 Intelligible voice modulation requires a bandwidth of:
a. 300 Hz.
b.* 2 to 3 KHz.
c. 5 to 10 KHz.
d. 10 KHz.
19 Over modulation of an A.M. signal is likely to cause:
a. Excessive deviation.
b. 10 sidebands.
c. Minimum interference.
d.* Severe splatter on adjacent frequencies.
20 The Audio modulation signal on an FM transmitter varies the:
a.* Transmitter output power.
b. Level of drive applied to the final.
c. Carrier output frequency.
d. Microphone gain of the transmitter.
21 What usually results if a voice transmitter is over modulated?
a. Increased carrier power.
b. Improved fade margin.
c. Improved fidelity.
d.* Excessive bandwidth.
22 Key clicks can be minimized by:
a. Using thin key leads.
b.* Damping the key switching circuits.
c. sending slow Morse code.
d. reducing transmitter output power.
23 If key clicks are to be avoided in a Morse code transmission,
attention should be given in the transmitter to:
a. Stabilizing the power amplifier supply voltage.
b. The use of a linear method of bias.
c. Control of the oscillator frequency.
d.* Shaping of the wave envelope.
24 When keying the variable frequency oscillator of a transistor
Morse code transmitter, the greatest difficulty likely to be
encountered is:
a. Arcing at the key contacts.
b. Production of harmonics.
c. Dangerous voltages.
d.* Frequency instability.
25 The effect of key click interference is:
a.* Produce distorted CW signals.
b. Produce sparking at the contacts.
c. Reduce effective radiated power.
d. Generate excessive sidebands.
26 If a transmitter is overdriven it is likely to cause
a.* Harmonics.
b. Sub-harmonics.
c. A change in the modulation mode.
d. Small dc variations.
27 The first odd harmonic of 145,05 MHz is:
a. 48,35 MHz
b. 290,1 MHz
c.* 435,15 MHz
d. 725,25 MHz.
28 Interference is experienced on the 144MHz band from some 432MHz
crystal controlled equipment. The basic oscillation is around
12MHz. The most likely multiplication order is:
a. x2x3x3x2
b.* x2x2x3x3
c. x3x3x2x2
d. x3x2x3x2
29 To minimize unwanted radiation of out of band signals, a
transmitter should be followed by:
a. A low pass filter.
b.* A band pass filter.
c. A high pass filter.
d. A notch filter.
30 High power transmitting equipment in perfect working order may
create harmonic interference due to:
a. A broadcast receiver having a high pass filter.
b.* Non-linear elements in the receiving antenna system.
c. Linear electrical elements in the receiving antenna.
d. Poor VSWR conditions in the feed line.
31 Which of the following design features of a transmitter would
assist in the reduction of radiated harmonics in the output:
a.* A low pass filter between the audio amplifier and the
modulator.
b. Provision of a class C output stage.
c. Class AB operation of R.F. power amplifier.
d. Capacity coupling of the aerial to the anode circuit.
32 Which of the following bands are NOT harmonically related to
the 1810 to 1850 MHz band?
a. 7,000 to 7,100 MHz.
b.* 10,100 to 10,150 MHz.
c. 14,000 to 14,350 MHz.
d. 21,000 to 21,450 MHz.
33 Spurious resonances may occur in decoupling circuits. this is
due to:
a. The power supply.
b.* Self resonance of RF chokes.
c. Saturation of the core of RF chokes.
d. The resistive element of an RF choke.
34 Spurious oscillations caused by resonance of RF chokes can be
minimized by using:
a.* Low Q chokes.
b. Long power cables.
c. Non-inductive capacitors.
d. Non-resonant circuits.
35 An unwanted signal is generated by a transmitter each time it
is keyed. It is removed by installing a small capacitor on the
power supply terminals. This unwanted signal is called:
a. Chirp.
b. Harmonic distortion.
c.* Spurious Oscillation.
d. Key clicks.
36 Self oscillations can occur when the output of an amplifier is
coupled to:
a. An antenna.
b. A dummy load.
c. A pi- filter network.
d.* The amplifier input.
37 An R.F. power amplifier is found to oscillate at its
fundamental frequency when the R.F. drive is removed. This effect
is called:
a.* Self-oscillation.
b. Parasitic oscillation.
c. Harmonic oscillation.
d. Overload oscillation.
38 The cure for self oscillation of an audio amplifier is:
a. To increase voltage gain.
b. To filter the feedback signal.
c. To inductively couple the input stage.
d.* To introduce negative feedback.
39 The accuracy of the frequency of an amateur transmission can be
checked using :
a. A sensitive dip-meter.
b.* Reference crystal marker oscillator.
c. An SWR meter.
d. An absorption wave meter.
40 An accurate crystal calibrator or a Frequency counter can be
used to determine the:
a. Deviation of a transmitter.
b. Exact output power of the carrier.
c.* Carrier frequency.
d. Sideband used on an SSB transceiver.
41 An inductively coupled absorption wave meter can commonly be
used to provide:
a.* Relative Field strength readings.
b. Standing wave ratios.
c. True power readings.
d. Accurate frequency readings.
42 Insufficient carrier suppression on an SSB Signal will cause:
a. distortion.
b. poor readability.
c. difficulty to set the receiver BFO.
d.* heterodynes on the audio frequencies.
43 An AM receiver tuned to the carrier frequency of an unmodulated
lower side band signal tone will hear:
a.* Nothing.
b. A distorted signal of 4kHz.
c. A clear tone.
d. A fully quiet carrier.
44 The carrier of an SSB signal is removed by a circuit called:
a. A full wave rectifier.
b. A notch filter.
c.* A balanced modulator.
d. A discriminator.
45 To minimize mains hum on transmitted signals all DC power
supplies should:
a. use a low DC voltage.
b. use a screened transformer.
c. be RF decoupled.
d.* use smoothing and regulator circuits.
46 The output of a full wave rectifier is connected to a series
regulator to:
a.* produce a constant output voltage.
b. reduce power dissipation.
c. filter out harmonics.
d. reduce/limit the maximum current.
47 A 1000mfd capacitor across the DC output of a power supply
a. Will increase any 100Hz ripple present.
b. Improve low frequency response.
c.* Remove AC rectified mains hum.
d. Decrease smoothed output voltage.
48 To minimize interference on adjacent channels, voice
frequencies should be kept below:
a. 500Hz
b. 1kHz
c.* 3kHz
d. 5kHz
49 So as not to cause unnecessary sideband splatter the percentage
modulation of an AM signal must be kept below:
a. 25%
b. 50%
c. 75%
d* 100%
50 What causes splatter?
a. Inadequate harmonic suppression in the final amplifier.
b.* Excessive bandwidth of a transmitter.
c. A poorly regulated transmitter power supply.
d. Insufficient drive to the final amplifier.
51 Intermodulation caused by a linear SSB amplifier is due to:
a.* Over driving the power level of the amplifier.
b. The operating frequency being to high.
c. Harmonic distortion.
d. Two modulating frequencies occurring at the same time.
52 Over-driving an SSB Linear amplifier can cause:
a. Improved communication.
b. A louder audio signal.
c. Lower power consumption.
d.* Distortion and splatter.
53 Which of the following might be effective at reducing the risk
of parasitic oscillations in a low power VHF output stage?
a.* Ferrite beads on the emitter leads of the power device.
b. Ferrite beads on the microphone cable.
c. Ferrite beads in series with the microphone.
d. Ferrite beads on the loudspeaker leads.
54 Parasitic oscillations can cause interference, they are:
a. Of a very low frequency.
b. Always twice the operating frequency.
c.* High in frequency but not related to the operating frequency.
d. Always three times the operating frequency.
55 Any non-linear device will produce:
a.* Mixing products.
b. Amplification.
c. Filtering.
d. Key-clicks.
56 When a synthesized VFO oscillator is not locked to the
reference frequency, it will be:
a. Stable.
b. Equal to the reference frequency.
c.* Unstable.
d. Equal to the operating frequency.
57 A Domestic Receiver having an IF of 455kHz and receiving a
signal on 945kHz, experiences strong breakthrough from someone on
the 160m band. This could be caused by second channel interference
of:
a. 1,810 MHz.
b. 1,825 MHz.
c. 1,835 MHz.
d.* 1,855 MHz.
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