MCQs in Antennas Part IX

This is the Multiples Choice Questions Part 9 of the Series in Antennas as one of the Communications Engineering topic. In Preparation for the ECE Board Exam make sure to expose yourself and familiarize in each and every questions compiled here taken from various sources including but not limited to past Board Examination Questions in Electronic System and Technologies, Communications Books, Journals and other Communications References.

Online Questions and Answers Topic Outline

• MCQs in Basic considerations
• MCQs in Wire Radiators in Space
• MCQs in Isotropic Radiator
• MCQs in Current and Voltage Distributions
• MCQs in Resonant and Non-resonant Antennas
• MCQs in Antenna Terms and Definition
• MCQs in Antenna Gain and Resistance
• MCQs in Bandwidth, Beamwidth and Polarization
• MCQs in Grounded and Ungrounded Antennas
• MCQs in Grounding Systems and Matching Systems
• MCQs in Antenna Types
• MCQs in Directional and Non-directional Antennas
• MCQs in Microwave Antennas
• MCQs in Wideband and Special Purpose Antennas

MCQs in Antennas Series

Following is the list of multiple choice questions in this brand new series:

Antennas MCQs

PART 1: MCQs from Number 1 – 50                        Answer key: PART I

PART 2: MCQs from Number 51 – 100                   Answer key: PART II

PART 3: MCQs from Number 101 – 150                 Answer key: PART III

PART 4: MCQs from Number 151 – 200                 Answer key: PART IV

PART 5: MCQs from Number 201 – 250                 Answer key: PART V

PART 6: MCQs from Number 251 – 300                 Answer key: PART VI

PART 7: MCQs from Number 301 – 350                 Answer key: PART VII

PART 8: MCQs from Number 351 – 400                 Answer key: PART VIII

PART 9: MCQs from Number 401 – 450                 Answer key: PART IX

PART 10: MCQs from Number 451 – 500                 Answer key: PART X

SEE: More Questions and Answers in Antennas

Continue Practice Exam Test Questions Part IX of the Series

401. An ungrounded antenna near the ground

• a. Acts as a single antenna of twice the height
• b. Is unlikely to need an earth mat
• c. Acts as an antenna array
• d. Must be horizontally polarized

402. One of the following consists of nonresonant antennas:

• a. The rhombic antenna
• b. The folded dipole
• c. The end-fire array
• d. The broadside array

403. One of the following is very useful as a multiband HF receiving antenna. This is the:

• a. Conical horn
• b. Folded dipole
• c. Log-periodic
• d. Square loop

404. Which of the following antennas is best excited from a waveguide?

• a. Biconical
• b. Horn
• c. Helical
• d. Discone

405. Indicate which of the following reasons for using a counterpoise with antennas is false:

• a. Impossibility of a good ground connection
• b. Protection of personnel working underneath
• c. Provision of an earth for the antenna
• d. Rockiness of the ground itself

406. One of the following is not a reason for the use of an antenna coupler:

• a. To make the antenna look resistive
• b. To provide the output amplifier with the correct load impedance
• c. To discriminate against harmonics
• d. To prevent reradiation of the local oscillator

407. Indicate the antenna that is not wideband

• a. Discone
• b. Folded dipole
• c. Helical
• d. Marconi

408. Indicate which one of the following reasons for the use of an earth mat with antennas is false:

• a. Impossibility of a good ground connection
• b. Provision of an earth for the antenna
• c. Protection of personnel working underneath
• d. Improvement of the radiation pattern of the antenna

409. Show which of the following terms does not apply to the Yagi-Uda array

• a. Good bandwidth
• b. Parasitic elements
• c. Folded dipole
• d. High gain

410. An antenna that is circularly polarized is the

• a. Helical
• b. Small circular loop
• c. Parabolic reflector
• d. Yagi-Uda

411. The standard reference antenna for the directive gain is the

• a. Infinitesimal dipole
• b. Isotropic antenna
• c. Elementary doublet
• d. Half-wave dipole

412. Top loading is sometimes used with an antenna in order to increase its

• a. Effective height
• b. Bandwidth
• c. Beamwidth
• d. Input capacitance

413. Cassegrain feed is used with a parabolic reflector to

• a. Increase the gain of the system
• b. Increase the beamwidth of the system
• c. Reduce the size of the main reflector
• d. Allow the feed to be places at a convenient point

414. Zoning is used with a dielectric antenna in order to

• a. Reduce the bulk of the lens
• b. Increase the bandwidth of the lens
• c. Permit pin-point focusing
• d. Correct the curvature of the wavefront from a horn that is too short

415. A helical antenna is used for satellite tracking because of its

• a. Circular polarization
• b. Maneuverability
• c. Broad bandwidth
• d. Good front-to-back ratio

416. The discone antenna is

• a. A useful direction-finding antenna
• b. Used as a radar receiving antenna
• c. Circularly polarized like other circular antennas
• d. Useful as a UHF receiving antenna

417. One of the following is not omnidirectional antenna

• a. Half-wave dipole
• b. Log-periodic
• c. Discone
• d. Marconi

418. The polarization of a discone antenna is ______________.

• a. Horizontal
• b. Vertical
• c. Omni
• d. Directional

419. _____________ is the horizontal pointing angle of an antenna.

• a. Right angle
• b. Angle of elevation
• c. Bandwidth
• d. Azimuth

420. Which is a properly terminated antenna?

• a. Rhombic
• b. Hertz
• c. Marconi
• d. Dipole

421. ____________ is a device that detects both vertically and horizontally polarized signals simultaneously.

• a. Crystal
• b. Orthomode transducer
• c. Light transducer
• d. Optoisolator

422. How much does the radiated power of an antenna increases if its current increased by 3.3 times?

• a. 6.6 times
• b. 3.3 times
• c. 10.89 times
• d. 9.9 times

423. What do you call the energy that was not radiated into space or completely transmitted?

• a. Incident waves
• b. Captured waves
• c. Standing waves
• d. Modulated waves

424. What is the estimated medium wind loading in the Philippines for antenna tower design?

• a. 200 kph
• b. 250 kph
• c. 300 kph
• d. 100 kph

425. The minimum number of turns a helix antenna must have

• a. 4
• b. 5
• c. 3
• d. 6

426. When testing transmitter to prevent interfering with other stations, which type of antenna must be used?

• a. Dummy antenna
• b. Herztian antenna
• c. None
• d. Void antenna

427. A device that radiates electromagnetic energy and/or intercepts electromagnetic radiation

• a. Antenna
• b. Transmitter
• c. Transmission line
• d. Transceiver

428. Determine the gain of a 6 ft parabolic dish operating at 1800 MHz

• a. 15.5 dB
• b. 30 dB
• c. 11.2 dB
• d. 28.17 dB

429. Radiation characteristic of a dipole

• a. figure of eight
• b. omnidirectional
• c. bi-directional
• d. unidirectional

430. An antenna which is not resonant at particular frequencies and so can be used over a wide band of frequencies is called

• a. Aperiodic
• b. Cassegrain
• c. Top-loaded
• d. Boresight

431. Two wires that are bent 90 degrees apart.

• a. Rhombic
• b. Hertz
• c. Dipole
• d. Log-periodic

432. Harmonic suppressor connected to an antenna

• a. Tank circuit
• b. M-derived filter
• c. Low-pass filter
• d. High-pass filter

433. Theoretical gain of a Herztian dipole

• a. 0 dB
• b. 1.76 dB
• c. 2.15 dB
• d. 3 dB

434. A helical antenna is used for satellite tracking because of

• a. Maneuverability
• b. Good front-to-back
• c. Circular polarization
• d. Broad bandwidth

435. A convenient method of determining antenna impedance

• a. Reactance circle
• b. Stub matching
• c. Smith chart
• d. Trial and error

436. Unity gain antenna.

• a. Half-wave dipole
• b. Rhombic
• c. Dummy
• d. Isotropic

437. EIRP stands for ______________________.

• a. Effective isotropic reflected power
• b. Effective isotropic refracted power
• c. Efficient and ideal radiated power
• d. Effective isotropic radiated power

438. Which of the following refers to the smallest beam of satellite antenna’s radiation pattern?

• a. Global beam
• b. Zoom beam
• c. Spot beam
• d. Hemispheric beam

439. A region in front of a parabolic antenna

• a. Transmission zone
• b. Fraunhofer
• c. Fresnel
• d. All of these

440. An antenna that can only receive a television signal.

• a. Isotropic antenna
• b. Reference antenna
• c. TVRO
• d. Yagi antenna

441. Radiation pattern of a discone

• a. Figure of eight
• b. Bi-directional
• c. Omnidirectional
• d. Unidirectional

442. Radio wave concentration in the direction of the signal emitted by a directional antenna.

• a. Back lobe radiation
• b. Transmitted signal
• c. Side lobe radiation
• d. Major lobe radiation

443. The reflector and director of an antenna array are considered as:

• a. Transcendental elements
• b. Feed-points
• c. Driven elements
• d. Parasitic elements

444. An electronic equipment used to measure standing wave ratio:

• a. Altimeter
• b. Multimeter
• c. Reflectometer
• d. Wavemeter

445. The product of the power supplied to the antenna and its gain relative to a half-wave dipole in a given direction.

• a. Rated power
• b. ERP
• c. Peak envelope power
• d. Carrier power

446. What makes an antenna physically long electronically short?

• a. Adding C in series
• b. Top loading
• c. Adding L in series
• d. All of these

447. The capture area of an antenna is directly proportional to the

• a. Distance between transmitter and receiver
• b. Power density of the signal
• c. Gain of the antenna
• d. Frequency of the received signal

448. A type of an undergrounded antenna is a/an ________________.

• a. Hertz
• b. Isotropic
• c. Parabolic
• d. Marconi

449. What is meant by antenna gain?

• a. The ratio of the signal in the forward direction to the signal in the backward direction
• b. The ratio of the amount of power produced by the antenna compared to the output power of the transmitter
• c. The final amplifier gain minus the transmission line losses (including any phasing lines present)
• d. The numeric ratio relating the radiated signal strength of an antenna to that of another antenna

450. It consists of a number of dipoles of equal size, equally spaces along a straight line with all dipoles fed in the same phase from the same source.

• a. End-fire array
• b. Yagi antenna
• c. Log-periodic antenna
• d. Broadside array

Complete List of MCQs in Communications Engineering per topic

Series of Multiple Choice Questions in Electronics Systems and Technologies

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