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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