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2024 Amateur Extra pool
15 / 602 questions need explanations
97.5% complete
All explanations are written and maintained by ordinary users like you! Please help us finish the explanations in this pool.
E3
B01
Where is transequatorial propagation (TEP) most likely to occur?
A.
Between points separated by 2,000 miles to 3,000 miles over a path perpendicular to the geomagnetic equator
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B.
Between points located 1,500 miles to 2,000 miles apart on the geomagnetic equator
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C.
Between points located at each other’s antipode
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D.
Through the region where the terminator crosses the geographic equator
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E4
B09
Which of the following can be measured by a two-port vector network analyzer?
A.
Phase noise
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B.
Filter frequency response
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C.
Pulse rise time
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D.
Forward power
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E5
D07
What combines to create the self-resonance of a component?
A.
The component’s resistance and reactance
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B.
The component’s nominal and parasitic reactance
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C.
The component’s inductance and capacitance
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D.
The component’s electrical length and impedance
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E5
D08
What is the primary cause of loss in film capacitors at RF?
A.
Inductance
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B.
Dielectric loss
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C.
Self-discharge
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D.
Skin effect
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E6
B06
Which of the following is a common use of a Schottky diode?
A.
In oscillator circuits as the negative resistance element
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B.
As a variable capacitance in an automatic frequency control circuit
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C.
In power supplies as a constant voltage reference
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D.
As a VHF/UHF mixer or detector
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E6
C05
Which of the following digital logic families has the lowest power consumption?
A.
Schottky TTL
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B.
ECL
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C.
NMOS
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D.
CMOS
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E7
B03
What circuit is required at the output of an RF switching amplifier?
A.
A filter to remove harmonic content
(0% chose this)
B.
A high-pass filter to compensate for low gain at low frequencies
(0% chose this)
C.
A matched load resistor to prevent damage by switching transients
(0% chose this)
D.
A temperature compensating load resistor to improve linearity
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E7
B09
What is characteristic of an emitter follower (or common collector) amplifier?
A.
Low input impedance and phase inversion from input to output
(0% chose this)
B.
Differential inputs and single output
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C.
Acts as an OR circuit if one input is grounded
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D.
Input and output signals in-phase
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E9
C05
What is the purpose of feeding an off-center-fed dipole (OCFD) between the center and one end instead of at the midpoint?
A.
To create a similar feed point impedance on multiple bands
(0% chose this)
B.
To suppress off-center lobes at higher frequencies
(0% chose this)
C.
To resonate the antenna across a wider range of frequencies
(0% chose this)
D.
To reduce common-mode current coupling on the feed line shield
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E9
D12
What is the purpose of making a Yagi’s parasitic elements either longer or shorter than resonance?
A.
Wind torque cancellation
(0% chose this)
B.
Mechanical balance
(0% chose this)
C.
Control of phase shift
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D.
Minimize losses
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E9
H06
What indicates the correct value of terminating resistance for a Beverage antenna?
A.
Maximum feed point DC resistance at the center of the desired frequency range
(0% chose this)
B.
Minimum low-angle front-to-back ratio at the design frequency
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C.
Maximum DC current in the terminating resistor
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D.
Minimum variation in SWR over the desired frequency range
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E9
H07
What is the function of a Beverage antenna’s termination resistor?
A.
Increase the front-to-side ratio
(0% chose this)
B.
Absorb signals from the reverse direction
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C.
Decrease SWR bandwidth
(0% chose this)
D.
Eliminate harmonic reception
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E9
H09
What type of radiation pattern is created by a single-turn, terminated loop such as a pennant antenna?
A.
Cardioid
(0% chose this)
B.
Bidirectional
(0% chose this)
C.
Omnidirectional
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D.
Hyperbolic
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E0
A07
What is meant by “100% tie-off” regarding tower safety?
A.
All loose ropes and guys secured to a fixed structure
(0% chose this)
B.
At least one lanyard attached to the tower at all times
(0% chose this)
C.
All tools secured to the climber’s harness
(0% chose this)
D.
All circuit breakers feeding power to the tower must be tied closed with tape, cable, or ties
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E0
A09
Which of the following types of equipment are exempt from RF exposure evaluations?
A.
Transceivers with less than 7 watts of RF output
(0% chose this)
B.
Antennas that radiate only in the near field
(0% chose this)
C.
Hand-held transceivers sold before May 3, 2021
(0% chose this)
D.
Dish antennas less than one meter in diameter
(0% chose this)
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