Lesson 8: Modulation Modes

Question 1

What is the impact of using excessive effective radiated power on a satellite uplink?

A. Possibility of commanding the satellite to an improper mode

B. Blocking access by other users

C. Overloading the satellite batteries

D. Possibility of rebooting the satellite control computer

Answer 1

B. Blocking access by other users

Question 2

Which sideband is normally used for 10 meter HF, VHF, and UHF single-sideband communications?
Choose only ONE best answer.

A
A. Upper sideband
B
B. Lower sideband
C
C. Suppressed sideband
D
D. Inverted sideband

Answer 2

A. Upper sideband

Question 3

What is a characteristic of single sideband (SSB) compared to FM?

Choose only ONE best answer.

A
A. SSB signals are easier to tune in correctly

B
B. SSB signals are less susceptible to interference
C
C. SSB signals have narrower bandwidth
D
D. All of these choices are correct

Answer 3

C. SSB signals have narrower bandwidth

Note:
SSB (single sideband) emissions only use 3 kHz of bandwidth while FM voice transmissions use 10 kHz to 15 kHz of bandwidth. This narrow bandwidth is an advantage of SSB over FM for voice transmissions.

Question 4

What type of modulation is commonly used for VHF packet radio transmissions?

Choose only ONE best answer.

A
A. FM or PM

B
B. SSB
C
C. AM
D
D. PSK

Answer 4

A. FM or PM

Note:
FM (frequency modulation) is most commonly used for VHF packet radio transmissions. Many older FM transceivers without subaudible tone capabilities have found their way into ham radio packet communications. A packet repeater is called a digipeater.

Question 5

What operating activity involves contacting as many stations as possible during a specified period?
Choose only ONE best answer.

A
A. Contesting
B
B. Net operations
C
C. Public service events
D
D. Simulated emergency exercises

Answer 5

A. Contesting

Question 6

What is required before using the EchoLink system?

Choose only ONE best answer.

A
A. Complete the required EchoLink training

B
B. Purchase a license to use the EchoLink software

C
C. Register your call sign and provide proof of license

D
D. All these choices are correct

Answer 6

C. Register your call sign and provide proof of license

Question 7

What kind of data can be transmitted by APRS?

A. GPS position data

B. Text messages

C. Weather data

D. All these choices are correct

Answer 7

D. All these choices are correct

Question 8

Which of the following protocols enables an amateur station to transmit through a repeater without using a radio to initiate the transmission?

Choose only ONE best answer.

A
A. IRLP

B
B. D-STAR

C
C. DMR

D
D. EchoLink

Answer 8

D. EchoLink

Question 9

Which of the following is good procedure when contacting another station in a contest?

Choose only ONE best answer.

A
A. Sign only the last two letters of your call if there are many other stations calling
B
B. Contact the station twice to be sure that you are in his log
C
C. Send only the minimum information needed for proper identification and the contest exchange

D
D. All of these choices are correct

Answer 9

C. Send only the minimum information needed for proper identification and the contest exchange

Question 10

Which of the following is included in packet radio transmissions?

Choose only ONE best answer.

A
A. A check sum that permits error detection
B
B. A header that contains the call sign of the station to which the information is being sent
C
C. Automatic repeat request in case of error
D
D. All of these choices are correct

Answer 10

D. All of these choices are correct