What is an isotropic antenna?
- A grounded antenna used to measure Earth conductivity
- A horizontally polarized antenna used to compare Yagi antennas
- A theoretical, omnidirectional antenna used as a reference for antenna gain
- A spacecraft antenna used to direct signals toward Earth
What is the effective radiated power relative to a dipole of a repeater station with 150 watts transmitter power output, 2 dB feed line loss, 2.2 dB duplexer loss, and 7 dBd antenna gain?
- 1977 watts
- 78.7 watts
- 420 watts
- 286 watts
What is the radiation resistance of an antenna?
- The combined losses of the antenna elements and feed line
- The specific impedance of the antenna
- The value of a resistance that would dissipate the same amount of power as that radiated from an antenna
- The resistance in the atmosphere that an antenna must overcome to be able to radiate a signal
Which of the following factors affect the feed point impedance of an antenna?
- Transmission line length
- Antenna height
- The settings of an antenna tuner at the transmitter
- The input power level
What is included in the total resistance of an antenna system?
- Radiation resistance plus space impedance
- Radiation resistance plus transmission resistance
- Transmission-line resistance plus radiation resistance
- Radiation resistance plus loss resistance
What is the effective radiated power relative to a dipole of a repeater station with 200 watts transmitter power output, 4 dB feed line loss, 3.2 dB duplexer loss, 0.8 dB circulator loss, and 10 dBd antenna gain?
- 317 watts
- 2000 watts
- 126 watts
- 300 watts
What is the effective isotropic radiated power of a repeater station with 200 watts transmitter power output, 2 dB feed line loss, 2.8 dB duplexer loss, 1.2 dB circulator loss, and 7 dBi antenna gain?
- 159 watts
- 252 watts
- 632 watts
- 63.2 watts
What is antenna bandwidth?
- Antenna length divided by the number of elements
- The frequency range over which an antenna satisfies a performance requirement
- The angle between the half-power radiation points
- The angle formed between two imaginary lines drawn through the element ends
What is antenna efficiency?
- Radiation resistance divided by transmission resistance
- Radiation resistance divided by total resistance
- Total resistance divided by radiation resistance
- Effective radiated power divided by transmitter output
Which of the following improves the efficiency of a ground-mounted quarter-wave vertical antenna?
- Installing a radial system
- Isolating the coax shield from ground
- Shortening the radiating element
- All these choices are correct
Which of the following factors determines ground losses for a ground-mounted vertical antenna operating in the 3 MHz to 30 MHz range?
- The standing wave ratio
- Distance from the transmitter
- Soil conductivity
- Take-off angle
How much gain does an antenna have compared to a 1/2-wavelength dipole when it has 6 dB gain over an isotropic antenna?
- 3.85 dB
- 6.0 dB
- 8.15 dB
- 2.79 dB
What term describes station output, taking into account all gains and losses?
- Power factor
- Half-power bandwidth
- Effective radiated power
- Apparent power