B-006-09: Gain, directivity, radiation pattern, antenna bandwidth
B-006-09-01:
What is a parasitic beam antenna?
An antenna where some elements obtain their radio energy by induction or radiation from a driven element
An antenna where the driven element obtains its radio energy by induction or radiation from director elements
An antenna where all elements are driven by direct connection to the feed line
An antenna where wave traps are used to magnetically couple the elements
B-006-09-02:
How can the bandwidth of a parasitic beam antenna be increased?
Use larger diameter elements
Use traps on the elements
Use tapered-diameter elements
Use closer element spacing
B-006-09-03:
If a slightly shorter parasitic element is placed 0.1 wavelength away from an HF dipole antenna, what effect will this have on the antenna's radiation pattern?
A major lobe will develop in the horizontal plane, toward the parasitic element
A major lobe will develop in the horizontal plane, parallel to the two elements
A major lobe will develop in the vertical plane, away from the ground
The radiation pattern will not be affected
B-006-09-04:
If a slightly longer parasitic element is placed 0.1 wavelength away from an HF dipole antenna, what effect will this have on the antenna's radiation pattern?
A major lobe will develop in the horizontal plane, away from the parasitic element, toward the dipole
A major lobe will develop in the horizontal plane, parallel to the two elements
A major lobe will develop in the vertical plane, away from the ground
The radiation pattern will not be affected
B-006-09-05:
The property of an antenna, which defines the range of frequencies to which it will respond, is called its:
bandwidth
front-to-back ratio
impedance
polarization
B-006-09-06:
Approximately how much gain does a half-wave dipole have over an isotropic radiator?
2.1 dB
1.5 dB
3.0 dB
6.0 dB
B-006-09-07:
What is meant by antenna gain?
The numerical ratio relating the radiated signal strength of an antenna to that of another antenna
The numerical ratio of the signal in the forward direction to the signal in the back direction
The numerical ratio of the amount of power radiated by an antenna compared to the transmitter output power
The final amplifier gain minus the transmission line losses
B-006-09-08:
What is meant by antenna bandwidth?
The frequency range over which the antenna may be expected to perform well
Antenna length divided by the number of elements
The angle between the half-power radiation points
The angle formed between two imaginary lines drawn through the ends of the elements
B-006-09-09:
In free space, what is the radiation characteristic of a half-wave dipole?
Minimum radiation from the ends, maximum broadside
Maximum radiation from the ends, minimum broadside
Omnidirectional
Maximum radiation at 45 degrees to the plane of the antenna
B-006-09-10:
The gain of an antenna, especially on VHF and above, is quoted in dBi. The "i" in this expression stands for:
isotropic
ideal
ionosphere
interpolated
B-006-09-11:
The front-to-back ratio of a beam antenna is:
the ratio of the maximum forward power in the major lobe to the maximum backward power radiation
the forward power of the major lobe to the power in the backward direction both being measured at the 3 dB points
undefined
the ratio of the forward power at the 3 dB points to the power radiated in the backward direction
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