Polarization, helical beam, parabolic antennas
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Canadian Advanced Exam Question Bank

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A-007-05: Polarization, helical beam, parabolic antennas

A-007-05-01: What is meant by circularly polarized electromagnetic waves?

Waves with a rotating electric field

Waves with an electric field bent into circular shape

Waves that circle the earth

Waves produced by a circular loop antenna



A-007-05-02: What is the polarization of an electromagnetic wave if its magnetic field is parallel to the surface of the Earth?

Vertical

Elliptical

Circular

Horizontal



A-007-05-03: What is the polarization of an electromagnetic wave if its magnetic field is perpendicular to the surface of the Earth?

Horizontal

Vertical

Circular

Elliptical



A-007-05-04: The polarization of a radio wave is taken as the direction of the lines of force in the _______ field:

electric

force

magnetic

electromagnetic



A-007-05-05: A transmitted wave is vertically polarized when:

its electrical component is vertical

the antenna is pointing north in the northern hemisphere

the antenna is parallel to the ground

its magnetic component is vertical



A-007-05-06: The polarisation of an antenna is the:

orientation of its radiated electric field

orientation of its radiated magnetic field

length of the radiating element

radiation angle



A-007-05-07: A parabolic antenna is very efficient because:

all the received energy is focused to a point where the pick-up antenna is located

a dipole antenna can be used to pick up the received energy

no impedance matching is required

a horn-type radiator can be used to trap the received energy



A-007-05-08: A helical-beam antenna with right-hand polarization will best receive signals with:

right-hand polarization

left-hand polarization

vertical polarization only

horizontal polarization



A-007-05-09: One antenna which will respond simultaneously to vertically- and horizontally-polarized signals is the:

helical-beam antenna

folded dipole antenna

ground-plane antenna

quad antenna



A-007-05-10: What precaution should you take whenever you make adjustments to the feed system of a parabolic dish antenna?

Be sure no one can activate the transmitter

Disconnect the antenna-positioning mechanism

Point the dish away from the sun so it doesn't concentrate solar energy on you

Be sure you and the antenna structure are properly grounded



A-007-05-11: Why should a protective fence be placed around the base of a ground-mounted parabolic dish transmitting antenna?

To reduce the possibility of persons being harmed by RF energy during transmissions

To reduce the possibility that animals will damage the antenna

To increase the property value through increased security awareness

To protect the antenna from lightning damage and provide a good ground system for the installation





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A-007-06: Losses in real antenna systems, effective radiated power
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