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30 Cards in this Set
- Front
- Back
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3-63J1
Which of the following could cause a high standing wave ratio on a transmission line? |
A detuned antenna coupler
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3-63J2
Why is the value of the radiation resistance of an antenna important? |
Knowing the radiation resistance makes it possible to match impedances for maximum power transfer
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3-63J3
A radio frequency device that allows RF energy to pass through in one direction with very little loss but absorbs RF power in the opposite direction is a: |
Isolator
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3-63J4
What is an advantage of using a trap antenna? |
It may be used for multiband operation
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3-63J5
What is meant by the term radiation resistance of an antenna? |
An equivalent resistance that would dissipate the same amount of power as that radiated from an antenna
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3-63J6
What is meant by the term antenna bandwidth? |
The frequency range over which an antenna can be expected to perform well
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3-64J1
What is the current flowing through a 52 ohm line with an input of 1,872 watts? |
6 amps
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3-64J2
The voltage produced in a receiving antenna is: |
Always proportional to the received field strength
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3-64J3
Which of the following represents the best standing wave ratio (SWR)? |
1:1
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3-64J4
At the ends of a half-wave antenna, what values of current and voltage exist compared to the remainder of the antenna? |
Minimum voltage and minimum current
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3-64J5
An antenna radiates a primary signal of 500 watts output. If there is a 2nd harmonic output of 0.5 watt, what attenuation of the 2nd harmonic has occurred? |
30 dB
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3-64J6
There is an improper impedance match between a 30 watt transmitter and the antenna, with 5 watts reflected. How much power is actually radiated? |
25 watts
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3-65J1
A vertical 1/4 wave antenna receives signals: |
Equally from all horizontal directions
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3-65J2
The resonant frequency of a Hertz antenna can be lowered by: |
Placing an inductance in series with the antenna
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3-65J3
An excited 1/2 wavelength antenna produces: |
Both electro-magnetic and electro-static fields
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3-65J4
To increase the resonant frequency of a 1/4 wavelength antenna: |
Add a capacitor in series
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3-65J5
What happens to the bandwidth of an antenna as it is shortened through the use of loading coils? |
It is decreased
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3-65J6
To lengthen an antenna electrically, add a: |
Coil
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3-66J1
What is the meaning of the term velocity factor of a transmission line? |
The velocity of the wave on the transmission line divided by the velocity of light in a vacuum
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3-66J2
What determines the velocity factor in a transmission line? |
Dielectrics in the line
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3-66J3
Nitrogen is placed in transmission lines to: |
Prevent moisture from entering the line
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3-66J4
A perfect (no loss) coaxial cable has 7 dB of reflected power when the input is 5 watts. What is the output of the transmission line? |
1 watt
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3-66J5
Referred to the fundamental frequency, a shorted stub line attached to the transmission line to absorb even harmonics could have a wavelength of: |
1/4 wavelength
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3-66J6
If a transmission line has a power loss of 6 dB per 100 feet, what is the power at the feed point to the antenna at the end of a 200 foot transmission line fed by a 100 watt transmitter? |
6 watts
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3-67J1
What is the effective radiated power of a repeater with 50 watts transmitter power output, 4 dB feedline loss, 3 dB duplexer and circulator loss, and 6 dB antenna gain? |
39.7 watts
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3-67J2
What is the effective radiated power of a repeater with 75 watts transmitter power output, 4 dB feedline loss, 3 dB duplexer and circulator loss, and 10 dB antenna gain? |
150 watts
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3-67J3
What is the effective radiated power of a repeater with 75 watts transmitter power output, 5 dB feedline loss, 4 dB duplexer and circulator loss, and 6 dB antenna gain? |
37.6 watts
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3-67J4
What is the effective radiated power of a repeater with 100 watts transmitter power output, 4 dB feedline loss, 3 dB duplexer and circulator loss, and 7 dB antenna gain? |
100 watts
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3-67J5
What is the effective radiated power of a repeater with 100 watts transmitter power output, 5 dB feedline loss, 4 dB duplexer and circulator loss, and 10 dB antenna gain? |
126 watts
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3-67J6
What is the effective radiated power of a repeater with 50 watts transmitter power output, 5 dB feedline loss, 4 dB duplexer and circulator loss, and 7 dB antenna gain? |
31.5 watts
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