# Blake: MCQ in Satellite Communications

(Last Updated On: January 10, 2018)

This is the Multiple Choice Questions in Chapter 20: Satellite Communications 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 height of the geosynchronous orbit above the equator is about:

• a. 3,578 km
• b. 35,780 km
• c. 357,800 km
• d. depends on satellite velocity

ANS: B

2. The high and low points of a satellite’s orbit are called, respectively,:

• a. apogee and perigee
• b. perigee and apogee

ANS: A

3. The area on the earth that is "covered" by a satellite is called its:

• a. earth station
• c. footprint
• d. plate

ANS: C

4. The velocity required to stay in orbit:

• a. is constant
• b. is zero (freefall)
• c. is lower close to the earth than far from the earth
• d. is higher close to the earth than far from the earth

ANS: D

5. An antenna is aimed by adjusting the two "look angles" called:

• a. azimuth and elevation
• b. azimuth and declination
• c. declination and elevation
• d. apogee and perigee

ANS: A

6. The power per transponder of a typical Ku-band satellite is in the range:

• a. 5 to 25 watts
• b. 50 to 250 watts
• c. 500 to 2500 watts
• d. depends on its orbit

ANS: B

7. The power level for an earth station to transmit to a satellite is on the order of:

• a. 101 watts
• b. 102 watts
• c. 103 watts
• d. 104 watts

ANS: C

8. The "payload" on a communications satellite consists of:

• a. transponders
• b. batteries
• c. solar cells
• d. all of the above

ANS: A

9. "Station-keeping" refers to:

• a. antenna maintenance
• d. none of the above

ANS: C

10. DBS stands for:

• a. decibels of signal
• b. down-beam signal

ANS: D

11. LNA stands for:

• a. low-noise amplifier
• b. low north angle
• c. low-noise amplitude
• d. low-noise array

ANS: A

12. A reduction in TWT power for linearity is called:

• a. backdown
• b. backoff
• c. power-down
• d. EIRP drop

ANS: B

13. TVRO stands for:

• b. television repeater only
• c. television remote origin
• d. none of the above

ANS: A

14. TDMA stands for:

• a. transponder-directed multiple antennas
• b. television distribution master antenna
• c. time-division multiple access
• d. transmit delay minimum aperture

ANS: C

15. VSAT stands for:

• a. video satellite
• b. video signal antenna terminal
• c. very small antenna terminal
• d. very small aperture terminal

ANS: D

16. On the uplink from a terminal, a VSAT system uses:

• a. high power to a small antenna
• b. low power to a small antenna
• c. low power to a large antenna
• d. LEO satellites

ANS: B

17. A typical VSAT system is configured as a:

• a. star
• b. mesh
• c. ring
• d. repeater

ANS: A

18. LEO stands for:

• a. long elliptic orbit
• b. low-earth orbit
• c. lateral earth orbit
• d. longitudinal earth orbit

ANS: B

19. For real-time communication, LEO systems require:

• a. a constellation of satellites
• b. tracking dish antennas
• c. very high power
• d. all of the above

ANS: A

20. The frequency bands used by Ku-band satellites are:

• a. 4 GHz and 6 GHz
• b. 12 GHz and 14 GHz
• c. 20 GHz and 30 GHz
• d. none of the above

ANS: B

COMPLETION

1. A satellite in geosynchronous orbit takes ____________________ hours to complete one orbit.

ANS: 24

2. The ____________________ is the signal path from the earth station to the satellite.

3. The ____________________ is the signal path from the satellite to the earth station.

4. A satellite in a ____________________ orbit appears to stay directly above one spot on the equator.

ANS: geostationary

5. Non-geostationary satellites are sometimes called ____________________ satellites.

ANS: orbital

6. A geosynchronous orbit is about ____________________ km above the earth.

ANS: 35,780

7. A ____________________ is an outline of the area on the earth’s surface that a satellite broadcasts to.

ANS: footprint

8. All satellite orbits are ____________________ in shape.

ANS: elliptical

9. The ____________________ is the distance of a satellite’s closest approach to the earth.

ANS: perigee

10. The ____________________ is a satellite’s farthest distance from the earth.

ANS: apogee

11. An antenna’s ____________________ is its angular direction between east and west.

ANS: azimuth

12. An antenna’s ____________________ is its vertical angle with respect to the earth’s surface.

ANS: elevation

13. An antenna’s ____________________ is the angle by which it is offset from the earth’s axis.

ANS: declination

14. Satellites using the ____________________ band operate on 12 GHz.

ANS: Ku

15. The time for a signal to make a round trip via satellite is about ____________________ milliseconds.

ANS: 500

16. A ____________________ is a type of repeater used on communications satellites.

ANS: transponder

17. Both the gain and the beamwidth of a dish antenna depend on its ____________________.

ANS: diameter

18. VSAT systems commonly use a ____________________ network configuration.

ANS: star

19. To date, LEO satellite systems have been a financial ____________________.

ANS: failure

20. C-band antennas are ____________________ than Ku-band antennas.

ANS: larger

1. A receiving antenna with a gain of 44.4 dBi looks at a sky with a noise temperature of 15 K. The loss between the output of the antenna and the input of the LNA is 0.4 dB, and the LNA has a noise temperature of 40 K. Calculate the G/T.

ANS:

25 dB

2. A receiver has a noise figure of 1.7 dB. Find its equivalent noise temperature.

ANS:

139 K.

3. A receiving antenna with a G/T of 25 dB is used to receive signals from a satellite 38,000 km away. The satellite has a 100-watt transmitter and an antenna with a gain of 30 dBi. The signal has a bandwidth of 1 MHz at a frequency of 12 GHz. Calculate the C/N at the receiver.

ANS:

38 dB

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