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1991-11-22
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13KB
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321 lines
111C-3.4 B 9-42 When it usually hottest because the|sun provides the energy that causes|both the ionization and the warming
When is E layer ionization at a maximum?
A. Dawn
B. Midday
C. Dusk
D. Midnight
*
112C-4.1 D 9-44 The critical frequency is usable, but |it's not optimum because it is subject|to rapid change at times
What is the name for the highest radio frequency that will
be refracted back to earth?
A. Lowest usable frequency
B. Optimum working frequency
C. Ultra high frequency
D. Critical frequency
*
113C-4.2 C 9-44 The amount of radiation received from |the sun which varies with the sun spot|cycles
What causes the maximum usable frequency to vary?
A. Variations in the temperature of the air at ionospheric
levels
B. Upper-atmospheric wind patterns
C. The amount of ultraviolet and other types of radiation
received from the sun
D. Presence of ducting
*
114C-4.3 A 9-44 The MUF is a little below the critical|frequency and is the maximum frequency|that allows good communications
What does the term maximum usable frequency refer to?
A. The maximum frequency that allows a radio signal to
reach its destination in a single hop
B. The minimum frequency that allows a radio signal to
reach its destination in a single hop
C. The maximum frequency that allows a radio signal to
be absorbed in the lowest ionospheric layer
D. The minimum frequency that allows a radio signal to
be absorbed in the lowest ionospheric layer
*
115C-5.1 C 9-45 A scatter-mode of propagation|like backscatter
When two stations are within each other's skip zone on the
frequency being used, what mode of propagation would it be
desirable to use?
A. Ground-wave propagation
B. Sky-wave propagation
C. Scatter-mode propagation
D. Ionospheric-ducting propagation
*
116C-5.2 C 9-45 A scatter-mode of propagation like|backscatter is probable
You are in contact with a distant station and are operating at a
frequency close to the maximum usable frequency. If the received
signals are weak and somewhat distorted, what type of propagation
are you probably experiencing?
A. Tropospheric ducting
B. Line-of-sight propagation
C. Backscatter propagation
D. Waveguide propagation
*
117C-6.1 A 9-46 Is it the same if there|is a tree in the path?
What is the transmission path of a wave that travels
directly from the transmitting antenna to the receiving
antenna called?
A. Line of sight
B. The sky wave
C. The linear wave
D. The plane wave
*
118C-6.2 B 9-46 You have direct waves|and reflected waves
How are VHF signals within the range of the visible
horizon propagated?
A. By sky wave
B. By direct wave
C. By plane wave
D. By geometric wave
*
119C-7.1 C 9-46 Troposphere
Ducting occurs in which region of the atmosphere?
A. F2
B. Ionosphere
C. Troposphere
D. Stratosphere
*
120C-7.2 A 9-46 Extends the Radio Horizon
What effect does tropospheric bending have on 2-meter radio
waves?
A. It increases the distance over which they can be transmitted
B. It decreases the distance over which they can be transmitted
C. It tends to garble 2-meter phone transmissions
D. It reverses the sideband of 2-meter phone transmissions
*
121C-7.3 D 9-46 Abnormal temperature pattern in|the atmosphere called inversion
What atmospheric phenomenon causes tropospheric ducting of
radio waves?
A. A very low pressure area
B. An aurora to the north
C. Lightning between the transmitting and receiving station
D. A temperature inversion
*
122C-7.4 A 9-46 Abnormal temperature pattern in|the atmosphere called inversion
Tropospheric ducting occurs as a result of what phenomenon?
A. A temperature inversion
B. Sun spots
C. An aurora to the north
D. Lightning between the transmitting and receiving station
*
123C-7.5 B 9-46 Abnormal temperature pattern in|the atmosphere called inversion
What atmospheric phenomenon causes VHF radio waves to
be propagated several hundred miles through stable air
masses over oceans?
A. Presence of a maritime polar air mass
B. A widespread temperature inversion
C. An overcast of cirriform clouds
D. Atmospheric pressure of roughly 29 inches of mercury
or higher
*
124C-7.5 D 9-46 In the Tech bands
In what frequency range does tropospheric ducting occur
most often?
A. LF
B. MF
C. HF
D. VHF
*
125D-1-1.1 C 8-13 Green is Ground and should |connect to the chassis as a|safety precaution
Where should the green wire in an ac line cord be attached
in a power supply?
A. To the fuse
B. To the "hot" side of the power switch
C. To the chassis
D. To the meter
*
126D-1-1.2 D 8-13 Black and red are Hot and are the|lead(s) that are normally fused
Where should the black (or red) wire in a three-wire line cord
be attached in a power supply?
A. To the filter capacitor
B. To the dc ground
C. To the chassis
D. To the fuse
*
127D-1-1.3 B 8-13 White for Without fuse|White is neutral and is|not normally fused
Where should the white wire in a three-wire line cord be
attached in a power supply?
A. To the side of the transformer's primary winding that
has a fuse
B. To the side of the transformer's primary winding without
a fuse
C. To the black wire
D. To the rectifier junction
*
128D-1-1.4 B 8-13 It is color coded to indicate|correct wiring polarity
Why is the retaining screw in one terminal of a light socket
made of brass while the other one is silver colored?
A. To prevent galvanic action
B. To indicate correct wiring polarity
C. To better conduct current
D. To reduce skin effect
*
129D-1-2.1 A 8-14 It depends on where it |flows, any is too much |.1 amperes may be fatal
How much electrical current flowing through the human body
is usually fatal?
A. As little as 100 milliamperes may be fatal
B. Approximately 10 amperes is required to be fatal
C. More than 20 amperes is needed to kill a human being
D. No amount of current will harm you. Voltages of over
2000 volts are always fatal, however
*
130D-1-2.2 A 8-14 If you're wet, even twelve volts will|shock and thirty volts is considered |to be dangerous to humans
What is the minimum voltage considered to be dangerous
to humans?
A. 30 volts
B. 100 volts
C. 1000 volts
D. 2000 volts
*
131D-1-2.3 A 8-14 For all of these safety questions|Select the lowest answer, Fifty|milliamperes etc.
How much electrical current flowing through the human body
is usually painful?
A. As little as 50 milliamperes may be painful
B. Approximately 10 amperes is required to be painful
C. More than 20 amperes is needed to be painful to a human
being
D. No amount of current will be painful. Voltages of over
2000 volts are always painful, however
*
132D-1-3.1 C 8-14 Should be a safety-switch inside|and the main power switch should|be easily reached
Where should the main power-line switch for a high voltage
power supply be situated?
A. Inside the cabinet, to interrupt power when the cabinet
is opened
B. On the rear panel of the high-voltage supply
C. Where it can be seen and reached easily
D. This supply should not be switch-operated
*
133D-2-1.1 B 8-15 A voltmeter is usually connected in |parallel with the circuit under test|Series won't allow current to flow
How is a voltmeter typically connected to a circuit
under test?
A. In series with the circuit
B. In parallel with the circuit
C. In quadrature with the circuit
D. In phase with the circuit
*
134D-2-2.1 C 8-15 By making a simple series voltage |divider with an external resistor |and the meter's internal resistance
How can the range of a voltmeter be extended?
A. By adding resistance in series with the circuit under test
B. By adding resistance in parallel with the circuit under test
C. By adding resistance in series with the meter
D. By adding resistance in parallel with the meter
*
135D-3-1.1 A 8-15 Watch Out! Wrong guess here will fry|the ammeter. An ammeter is usually|connected in series with the circuit
How is an ammeter typically connected to a circuit
under test?
A. In series with the circuit
B. In parallel with the circuit
C. In quadrature with the circuit
D. In phase with the circuit
*
136D-3-2.1 D 8-15 By adding an external current |shunt in parallel with the meter
How can the range of an ammeter be extended?
A. By adding resistance in series with the circuit under test
B. By adding resistance in parallel with the circuit under test
C. By adding resistance in series with the meter
D. By adding resistance in parallel with the meter
*
137D-4.1 D 8-16 As a minimum E I & R
What is a multimeter?
A. An instrument capable of reading SWR and power
B. An instrument capable of reading resistance, capacitance
and inductance
C. An instrument capable of reading resistance and reactance
D. An instrument capable of reading voltage, current and
resistance
*
138D-5-1.1 A 8-16 It would be hard to read at the |antenna and the FCC requires the|power measurement at transmitter
Where in the antenna transmission line should a peak-reading
wattmeter be attached to determine the transmitter output power?
A. At the transmitter output
B. At the antenna feed point
C. One-half wavelength from the antenna feed point
D. One-quarter wavelength from the transmitter output
*
139D-5-1.2 C 8-16 Placing a directional wattmeter at the|transmitter's output will give correct|power readings & allow SWR monitoring
For the most accurate readings of transmitter output power,
where should the RF wattmeter be inserted?
A. The wattmeter should be inserted and the output measured
one-quarter wavelength from the antenna feed point
B. The wattmeter should be inserted and the output measured
one-half wavelength from the antenna feed point
C. The wattmeter should be inserted and the output power
measured at the transmitter antenna jack
D. The wattmeter should be inserted and the output power
measured at the Transmatch output
*
140D-5-1.3 B 8-16 Except for video and TV|most things are 50 ohms
At what line impedance are RF wattmeters usually designed
to operate?
A. 25 ohms
B. 50 ohms
C. 100 ohms
D. 300 ohms
*
141D-5-1.4 A 8-16 Transmitter power is measured in watts|A directional wattmeter would indicate|which direction that power is moving
What is a directional wattmeter?
A. An instrument that measures forward or reflected power
B. An instrument that measures the directional pattern of
an antenna
C. An instrument that measures the energy consumed by the
transmitter
D. An instrument that measures thermal heating in a load
resistor
*
142D-5-2.1 B 8-16 Forward-Reflected
If a directional RF wattmeter indicates 90 watts forward
power and 10 watts reflected power, what is the actual
transmitter output power?
A. 10 watts
B. 80 watts
C. 90 watts
D. 100 watts
*
143D-5-2.2 C 8-16 Forward-Reflected
If a directional RF wattmeter indicates 96 watts forward
power and 4 watts reflected power, what is the actual
transmitter output power?
A. 80 watts
B. 88 watts
C. 92 watts
D. 100 watts
*
144D-6.1 A 8-17 A generator that produces |reference signals at known|frequencies
What is a marker generator?
A. A high-stability oscillator that generates a series
of reference signals at known frequency intervals
B. A low-stability oscillator that "sweeps" through a
bend of frequencies
C. An oscillator often used in aircraft to determine the
craft's location relative to the inner and outer
markers at airports
D. A high-stability oscillator whose output frequency
and amplitude can be varied over a wide range
*
145D-6.2 D 8-17 Uses a crystal oscillator
What type of circuit is used to inject a frequency
calibration signal into a communications receiver?
A. A product detector
B. A receiver incremental tuning circuit
C. A balanced modulator
D. A crystal calibrator
*
146D-6.3 A 8-17 Outputs a known frequency that|can be used to calibrate the |tuning dial on a receiver
How is a marker generator used?
A. To calibrate the tuning dial on a receiver
B. To calibrate the volume control on a receiver
C. To test the amplitude linearity of an SSB transmitter
D. To test the frequency deviation of an FM transmitter
*
147D-7.1 C 8-17 A signal generator produces a stable|signal that can be set to a specific|frequency
What piece of test equipment produces a stable, low-level
signal that can be set to a specific frequency?
A. A wavemeter
B. A reflectometer
C. A signal generator
D. A balanced modulator
*