# Blake: MCQ in Antenna

(Last Updated On: March 27, 2020) This is the Multiple Choice Questions in Chapter 16: Antenna from the book Electronic Communication Systems by Roy Blake . If you are looking for a reviewer in Communications Engineering this will definitely help. I can assure you that this will be a great help in reviewing the book in preparation for your Board Exam. Make sure to familiarize each and every questions to increase the chance of passing the ECE Board Exam.

#### Start Practice Exam Test Questions

Choose the letter of the best answer in each questions.

MULTIPLE CHOICE

1. The real part of an antenna’s input impedance is due to:

b. the reflected signal

c. the SWR

d. all of the above

Solution:

2. A half-wave dipole is sometimes called:

a. a Marconi antenna

b. a Hertz antenna

c. a Yagi antenna

d. none of the above

Solution:

3. The end-to-end length of a half-wave dipole antenna is actually:

a. one wavelength

b. one half-wavelength

c. slightly longer than a half-wavelength

d. slightly shorter than a half-wavelength

Solution:

4. The radiation of energy from an antenna can be seen in the:

a. standing wave pattern around the antenna

b. SWR along the feed cable

c. radiation resistance of the antenna

d. I2R loss of the antenna

Solution:

5. Measured on the ground, the field strength of a horizontally polarized half-wave dipole antenna is

strongest:

a. in one direction

b. in two directions

c. in all directions

d. depends on the number of elements

Solution:

6. The ability of an antenna to radiate more energy in one direction than in other directions is called:

a. directivity

b. selectivity

c. active antenna

d. resonance

Solution:

7. The front-to-back ratio of a half-wave dipole antenna is:

a. 0 dB

b. 3 dB

c. 10 dB

d. infinite

Solution:

8. An antenna’s beamwidth is measured:

a. from +90° to –90°

b. from front to back

c. between half-power points

d. between the minor side-lobes

Solution:

9. ERP stands for:

Solution:

10. “Ground Effects” refers to the effects on an antenna’s radiation pattern caused by:

a. radio signals reflecting off the ground

b. buildings and other structures on the ground

d. faulty connection of the feed cable ground

Solution:

11. A 1-MHz monopole antenna must be:

a. mounted vertically

b. mounted horizontally

c. at least one half-wavelength long

d. at least one wavelength long

Solution:

12. The typical antenna in an AM radio is a:

a. dipole

b. folded dipole

c. ferrite “loop-stick”

d. none of the above

Solution:

13. The polarization of plane waves received from a satellite is changed by:

a. gamma rays

c. helical rotation

d. the distance traveled

Solution:

14. A nonresonant antenna:

a. will not transmit

c. will cause SWR on the feed cable

d. all of the above

Solution:

15. At resonance, the input impedance to a lossless antenna should be:

a. resistive

b. inductive

c. capacitive

d. infinite

Solution:

16. An antenna can be matched to a feed line using:

a. a shorted stub

c. an LC network

d. all of the above

Solution:

17. As the length of a “long-wire” antenna is increased:

a. the number of lobes increases

b. the number of nodes decreases

c. efficiency decreases

d. none of the above

Solution:

18. Arrays can be:

a. phased

b. driven

c. parasitic

d. all of the above

Solution:

19. An array with one driven element, a reflector, and one or more directors is called a:

a. Marconi

b. Yagi

c. Log-Periodic Dipole

d. stacked array

Solution:

20. LPDA stands for:

a. Low-Power Dipole Array

b. Low-Power Directed Array

c. Log-Periodic Dipole Array

d. Log Power Dipole Array

Solution:

21. The radiated beam from a parabolic “dish” transmitting antenna is:

a. collimated

b. phased

c. dispersed

d. none of the above

Solution:

22. The energy picked up by a parabolic antenna is concentrated at the:

a. center

b. edges

c. focus

d. horn

Solution:

23. Antennas are often tested in:

a. an echo chamber

b. an anechoic chamber

c. a vacuum chamber

d. an RF reflective chamber

Solution:

24. Field strength at a distance from an antenna is measured with:

a. a slotted line

b. a dipole

c. an EIRP meter

d. a field-strength meter

Solution:

COMPLETION

1. An antenna is the interface between the transmission line and ____________________.

Solution:

2. Hertz antenna is another name for a half-wave ____________________.

Solution:

3. The length of a half-wave dipole is about ____________________ % of a half-wave in free space.

Solution:

4. The ____________________ resistance is the portion of an antenna’s input impedance due to transmitted radio waves leaving the antenna.

Solution:

5. Input impedance at the center feed point of a resonant half-wave dipole is about ____________________ W.

Solution:

6. Input impedance at the center feed point of a resonant folded dipole is about ____________________ W.

Solution:

7. The vertical angle of radiation is called the angle of ____________________.

Solution:

8. Antenna radiation patterns are typically drawn on graphs with ____________________ coordinates.

Solution:

9. As compared to a ____________________ source, a half-wave dipole has a gain of about 2 dBi.

point

isotropic

Solution:

10. Antenna gain measured in ____________________ is with reference to a half-wave dipole.

Solution:

11. ____________________ is the same as the gain for a lossless antenna.

Solution:

12. The front-to-back ratio of a half-wave dipole is ____________________ dB.

Solution:

13. The ____________________ of a directional antenna is the angle between its half-power points.

Solution:

14. ERP stands for ____________________ radiated power.

Solution:

15. ERP is the power input to the antenna multiplied by the antenna’s ____________________.

Solution:

16. A ____________________ is required to connect a coaxial cable to a center-fed dipole antenna.

Solution:

17. A horizontally mounted dipole will radiate waves with ____________________ polarization.

Solution:

18. A folded dipole has ____________________ bandwidth than a standard dipole.

wider

greater

more

Solution:

19. A monopole antenna is typically mounted in the ____________________ direction.

Solution:

20. The length of a typical monopole antenna is ____________________ wavelength.

Solution:

21. A monopole antenna mounted high on a tower typically uses a ____________________ plane.

Solution:

22. A vertical antenna has an _________________________ radiation pattern for ground-based receivers.

Solution:

23. The number of driven elements in a Yagi antenna is typically ____________________.

Solution:

24. The reflector on a Yagi antenna is called a ____________________ element.

Solution:

25. An LPDA is a ____________________ dipole array.

Solution:

26. If an LPDA had five elements, the number of driven elements it had would be ____________________.

Solution:

27. All the waves that hit the surface of a parabolic antenna merge at the ____________________.

Solution:

28. A ____________________ beam has all its individual rays parallel to each other.

Solution:

29. A microwave ____________________ antenna is essentially an extension of a waveguide.

Solution:

30. An ____________________ chamber is often used to test microwave antennas.

Solution:

1. Calculate the physical length of a half-wave dipole for use at 300 MHz.

Solution:

2. How much power will a 95% efficient antenna radiate if driven with 100 watts?

Solution:

3. If an antenna has 10.14 dB of gain compared to a point source, how much gain does it have compared to a half-wave dipole?

Solution:

4. What is the ERP of an antenna with 10 dBd of gain and driven by one watt?

Solution:

5. A resonant antenna has an input impedance of 100 ohms and is driven by 100 watts. What is the RMS current in the antenna?

Solution:

6. A resonant antenna has an input impedance of 100 ohms and is driven by 100 watts. What is the RMS voltage at the feed-point of the antenna?

Solution:

### Complete List of MCQ in Electronic Communication Systems by Blake

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