86 lines
3.1 KiB
Markdown
86 lines
3.1 KiB
Markdown
T9B – Feed lines: types, attenuation vs frequency, selecting; SWR concepts; Antenna tuners (couplers); RF Connectors: selecting, weather protection
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- [[T9B01]] (B)
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What is a benefit of low SWR? #card
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- A. Reduced television interference
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- B. Reduced signal loss
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- C. Less antenna wear
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- D. All these choices are correct
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- [[T9B02]] (B)
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What is the most common impedance of coaxial cables used in amateur radio? #card
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- A. 8 ohms
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- B. 50 ohms
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- C. 600 ohms
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- D. 12 ohms
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- [[T9B03]] (A)
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Why is coaxial cable the most common feed line for amateur radio antenna systems? #card
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- A. It is easy to use and requires few special installation considerations
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- B. It has less loss than any other type of feed line
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- C. It can handle more power than any other type of feed line
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- D. It is less expensive than any other type of feed line
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- [[T9B04]] (A)
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What is the major function of an antenna tuner (antenna coupler)? #card
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- A. It matches the antenna system impedance to the transceiver's output impedance
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- B. It helps a receiver automatically tune in weak stations
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- C. It allows an antenna to be used on both transmit and receive
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- D. It automatically selects the proper antenna for the frequency band being used
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- [[T9B05]] (D)
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What happens as the frequency of a signal in coaxial cable is increased? #card
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- A. The characteristic impedance decreases
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- B. The loss decreases
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- C. The characteristic impedance increases
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- D. The loss increases
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- [[T9B06]] (B)
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Which of the following RF connector types is most suitable for frequencies above 400 MHz? #card
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- A. UHF (PL-259/SO-239)
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- B. Type N
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- C. RS-213
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- D. DB-25
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- [[T9B07]] (C)
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Which of the following is true of PL-259 type coax connectors? #card
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- A. They are preferred for microwave operation
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- B. They are watertight
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- C. They are commonly used at HF and VHF frequencies
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- D. They are a bayonet-type connector
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- [[T9B08]] (D)
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Which of the following is a source of loss in coaxial feed line? #card
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- A. Water intrusion into coaxial connectors
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- B. High SWR
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- C. Multiple connectors in the line
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- D. All these choices are correct
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- [[T9B09]] (B)
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What can cause erratic changes in SWR? #card
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- A. Local thunderstorm
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- B. Loose connection in the antenna or feed line
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- C. Over-modulation
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- D. Overload from a strong local station
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- [[T9B10]] (C)
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What is the electrical difference between RG-58 and RG-213 coaxial cable? #card
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- A. There is no significant difference between the two types
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- B. RG-58 cable has two shields
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- C. RG-213 cable has less loss at a given frequency
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- D. RG-58 cable can handle higher power levels
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- [[T9B11]] (C)
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Which of the following types of feed line has the lowest loss at VHF and UHF? #card
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- A. 50-ohm flexible coax
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- B. Multi-conductor unbalanced cable
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- C. Air-insulated hardline
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- D. 75-ohm flexible coax
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- [[T9B12]] (A)
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What is standing wave ratio (SWR)? #card
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- A. A measure of how well a load is matched to a transmission line
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- B. The ratio of amplifier power output to input
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- C. The transmitter efficiency ratio
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- D. An indication of the quality of your station’s ground connection
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