Chapter 7: Antenna Basics, Standard Wave

Which of the following describes a simple dipole oriented parallel to Earth's surface?

• A ground-wave antenna

• A horizontally polarized antenna

• A travelling-wave antenna

• A vertically polarized antenna

Which of the following increases the resonant frequency of a dipole antenna?

• Lengthening it

• Inserting coils in series with radiating wires

• Shortening it

• Adding capacitive loading to the ends of the radiating wires

In which direction does a half-wave dipole antenna radiate the strongest signal?

• Equally in all directions

• Off the ends of the antenna

• In the direction of the feed line

• Broadside to the antenna

Tags

NGSS.HS-PS4-5

What is a beam antenna?

• An antenna built from aluminum I-beams

• An omnidirectional antenna invented by Clarence Beam

• An antenna that concentrates signals in one direction

• An antenna that reverses the phase of received signals

Tags

NGSS.HS-PS4-5

Which of the following types of antenna offers the greatest gain?

• 5/8 wave vertical

• Isotropic

• J pole

• Yagi

Tags

NGSS.HS-PS4-5

What is antenna gain?

• The additional power that is added to the transmitter power

• The additional power that is required in the antenna when transmitting on a higher frequency

• The increase in signal strength in a specified direction compared to a reference antenna

• The increase in impedance on receive or transmit compared to a reference antenna

Tags

NGSS.HS-PS4-3

NGSS.HS-PS4-5

What is the primary purpose of a dummy load?

• To prevent transmitting signals over the air when making tests

• To prevent over-modulation of a transmitter

• To improve the efficiency of an antenna

• To improve the signal-to-noise ratio of a receiver

What does a dummy load consist of?

• A high-gain amplifier and a TR switch

• A non-inductive resistor mounted on a heat sink

• A low-voltage power supply and a DC relay

• A 50-ohm reactance used to terminate a transmission line

What is the approximate length, in inches, of a quarter-wavelength vertical antenna for 146 MHz?

• 112

• 50

• 19

• 12

Tags

NGSS.HS-PS4-1

What is the approximate length, in inches, of a half-wavelength 6 meter dipole antenna?

•  6

• 50

• 112

• 236

Tags

NGSS.HS-PS4-1