E9A01

Which of the following describes an isotropic Antenna?

1. A theoretical antenna used as a reference for antenna gain

E9A02

How much gain does a 1/2-wavelength dipole have compared to an isotropic antenna?

1. 2.15 dB

E9A03

Which of the following antennas has no gain in any direction?

1. Isotropic antenna

E9A04

Why would one need to know the feed point impedance of an antenna?

1. To match impedances for maximum power transfer from a feed line

E9A05

Which of the following factors determine the radiation resistance of an antenna?

1. Antenna height and conductor length/diameter ratio, and location of nearby conductive objects

E9A06

What is the term for the ratio of the radiation resistance of an antenna to the total resistance of the system?

1. Antenna efficiency

E9A07

What is included in the total resistance of an antenna system?

1. Radiation resistance plus ohmic resistance

E9A08

What is a folded dipole antenna?

1. A dipole constructed from one wavelength of wire forming a very thin loop

E9A09

What is meant by antenna gain?

1. The numerical ratio relating the radiated signal strength of an antenna in the direction of maximum radiation to that of a reference antenna

E9A10

What is meant by antenna bandwidth?

1. The frequency range over which an antenna satisfies a performance requirement

E9A11

How is antenna efficiency calculated?

1. (radiation resistance / total resistance) x 100%

E9A12

How can the efficiency of an HF quarter-wave grounded vertical antenna be improved?

1. By installing a good radial system

E9A13

Which is the most important factor that determines ground losses for a ground-mounted vertical antenna operating in the 3-30 MHz range?

1. Soil conductivity

E 9A14

How much gain does an antenna have over a 1/2-wavelength dipole when it has 6 dB gain over an isotropic antenna?

1. 3.85 dB

E9A15

How much gain does an antenna have over a 1/2-wavelength dipole when it has 12 dB gain over an isotropic antenna?

1. 9.85 dB

E9A16

What is meant by the radiation resistance of an antenna?

1. The value of a resistance that would dissipate the same amount of power as that radiated from an antenna

NEXT

Go To TOC