Login or Register for FREE!
Subelement T9

ANTENNAS AND FEED LINES

Section T9B

Feed lines: types, attenuation vs frequency, selecting; SWR concepts; Antenna tuners (couplers); RF Connectors: selecting, weather protection

Which of the following connectors should be carefully taped for weather protection when used outdoors?

  • PL259
  • BNC
  • Type N
  • Correct Answer
    All these choices are correct
This question does not yet have an explanation! Register to add one

Tags: none

What is the most common impedance of coaxial cables used in amateur radio?

  • 8 ohms
  • Correct Answer
    50 ohms
  • 600 ohms
  • 12 ohms
This question does not yet have an explanation! Register to add one

Tags: none

Why is coaxial cable the most common feed line for amateur radio antenna systems?

  • Correct Answer
    It is easy to use and requires few special installation considerations
  • It has less loss than any other type of feed line
  • It can handle more power than any other type of feed line
  • It is less expensive than any other type of feed line
This question does not yet have an explanation! Register to add one

Tags: none

What is the major function of an antenna tuner (antenna coupler)?

  • Correct Answer
    It matches the antenna system impedance to the transceiver's output impedance
  • It helps a receiver automatically tune in weak stations
  • It allows an antenna to be used on both transmit and receive
  • It automatically selects the proper antenna for the frequency band being used
This question does not yet have an explanation! Register to add one

Tags: none

What happens as the frequency of a signal in coaxial cable is increased?

  • The characteristic impedance decreases
  • The loss decreases
  • The characteristic impedance increases
  • Correct Answer
    The loss increases
This question does not yet have an explanation! Register to add one

Tags: none

Which of the following connector types is most suitable as an RF connector for frequencies above 400 MHz?

  • PL-259
  • Correct Answer
    Type N
  • RS-213
  • DB-25
This question does not yet have an explanation! Register to add one

Tags: none

Which of the following is true of PL-259 type coax connectors?

  • They are preferred for microwave operation
  • They are watertight
  • Correct Answer
    They are commonly used at HF and VHF frequencies
  • They are a bayonet-type connector
This question does not yet have an explanation! Register to add one

Tags: none

Which of the following is a source of loss in coaxial feed line?

  • Water intrusion into coaxial connectors
  • High SWR
  • Multiple connectors in the line
  • Correct Answer
    All these choices are correct
This question does not yet have an explanation! Register to add one

Tags: none

What can cause erratic changes in SWR?

  • Local thunderstorm
  • Correct Answer
    Loose connection in the antenna or feed line
  • Over-modulation
  • Overload from a strong local station
This question does not yet have an explanation! Register to add one

Tags: none

What is the electrical difference between RG-58 and RG-213 coaxial cable?

  • There is no significant difference between the two types
  • RG-58 cable has two shields
  • Correct Answer
    RG-213 cable has less loss at a given frequency
  • RG-58 cable can handle higher power levels
This question does not yet have an explanation! Register to add one

Tags: none

Which of the following types of feed line has the lowest loss?

  • 50-ohm flexible coax
  • Multi-conductor unbalanced cable
  • Correct Answer
    Air-insulated hardline
  • 75-ohm flexible coax
This question does not yet have an explanation! Register to add one

Tags: none

What is standing wave ratio (SWR)?

  • Correct Answer
    A measure of how well a load is matched to a transmission line
  • The ratio of amplifier power output to input
  • The transmitter efficiency ratio
  • An indication of the quality of your station’s ground connection
This question does not yet have an explanation! Register to add one

Tags: none

Go to T9A Go to T0A