T9A_Ham Radio/Amateur Radio Technician License Question Pool

Описание: Group T9A - - Antennas: vertical and horizontal polarization, concept of antenna gain, definition and types of beam antennas, antenna loading, common portable and mobile antennas, relationships between resonant length and frequency, dipole pattern
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T9A01
What is a beam antenna?

An antenna that concentrates signals in one direction
T9A02
Which of the following describes a type of antenna loading?

Electrically lengthening by inserting inductors in radiating elements
T9A03
Which of the following describes a simple dipole oriented parallel to Earth's surface?

A horizontally polarized antenna
T9A04
What is a disadvantage of the short, flexible antenna supplied with most handheld radio transceivers, compared to a full-sized quarter-wave antenna?

It has low efficiency
T9A05
Which of the following increases the resonant frequency of a dipole antenna?

Shortening it
T9A06
Which of the following types of antenna offers the greatest gain?

Yagi
T9A07
What is a disadvantage of using a handheld VHF transceiver with a flexible antenna inside a vehicle?

Signal strength is reduced due to the shielding effect of the vehicle
T9A08
What is the approximate length, in inches, of a quarter-wavelength vertical antenna for 146 MHz?

19
T9A09
What is the approximate length, in inches, of a half-wavelength 6 meter dipole antenna?

112
T9A10
In which direction does a half-wave dipole antenna radiate the strongest signal?

Broadside to the antenna
T9A11
What is antenna gain?

The increase in signal strength in a specified direction compared to a reference antenna
T9A12
What is an advantage of a 5/8 wavelength whip antenna for VHF or UHF mobile service?

It has more gain than a 1/4-wavelength antenna