ESAT Pre-Board Exam 20

What is a period of a wave?

• The number of degrees in one cycle
• The number of zeros crossing in one cycle
• The amplitude of a wave
• The time required to complete one cycle

Which of the following colors of light rays has the shortest wavelength?

• yellow
• violet
• red
• blue

A device that connects two dissimilar networks and performs the protocol conversion.

• gateway
• coupler
• transformer
• converter

A major and basic advantage for the use of klystron.

• High power
• Efficiency
• Lesser noise
• Cheaper

A band where most military satellite often operate.

• Ku
• C
• X
• L

The final power amplifier in an FM transmitter usually operates class

• AB
• C
• B
• A

A radio land station in the land mobile service

• Mobile station
• Land station
• Base station
• Ship earth station

Where do the maximum current and minimum voltage values on a resonant Hertz dipole exist?

• Center of the antenna
• Near the end of the antenna
• Near the center of the antenna
• Ends of the antenna

How can the antenna efficiency of a HF grounded vertical antenna be made comparable to that of a half-wave antenna?

• By lengthening the vertical
• By shortening the vertical
• By installing a good ground radial system
• By isolating the coax shield from ground

At what distance is VHF propagation normally limited?

• Around 500 miles
• Around 1500 miles
• Around 2000 miles
• Around 1000 miles