AJX Radio engineering Exam Review

Question 1

What is SSR mode A?

Answer 1

The basic mode that is capable of discriminating an aircraft Identification code

Question 2

What determines the azimuth of a target?

Answer 2

The direction of the antenna

Question 3

Amplitude modulation causes generation of what?

Answer 3

Side bands

Question 4

Fill in the blanks:
To hear the ________, partial power of the ______ system is fed back to the _______ system through a detector to provide ______.

Answer 4

To hear the –voice being transmitted–, partial power of the –transmitting– system is fed back to the –receiving– system through a detector to provide –side tone–.

Question 5

Why does SSB system use one side band only?

Answer 5

Because either one side band contains all message information

Question 6

HF communication quality is deteriorated by what depending on the strength of the sun’s activity?

Answer 6

By magnetic storm or the Dellinger phenomenon

Question 7

Fill in the blanks:
When receiving signal is strong the voltage of the ____________is ___________and the receiver gain is ____________for preventing of ____________

Answer 7

When receiving signal is strong, the voltage of the –automatic gain control– is –high– and the receiver gain is –reduced– for preventing –overloading–

Question 8

A carrier wave is generated by what?

Answer 8

An oscillator

Question 9

Fill in the blanks:
The transmitter generates _________. The message signal________ the current. The modulated high-frequency current is fed to the_________.

Answer 9

The transmitter generates –high frequency electric current–. The message signal –modulates– the current. The modulated high-frequency current is fed to the –antenna–.

Question 10

Fill in the blanks:

In weak receiving conditions, the ACG voltage is __________to ________ the receiver gain

Answer 10

In weak receiving conditions, the AGC voltage is low to increase to receiver gain

Question 11

Radio equipment requires what type of power?

Answer 11

DC power

Question 12

What sort of antennas are applied to VHF and UHF range equipment?

Answer 12

Sleeve antenna, Brown antenna and Yagi antenna

Question 13

In the ionosphere which layer reflects HF radio waves

Answer 13

The F layer

Question 14

The side tone is what?

Answer 14

A feedback of the transmitting signal to the receiving system

Question 15

How is radar distance calculated?

Answer 15

From the elapsed time of the radio signal spent for the round trip between the antenna and the target

Question 16

The Yagi antenna is what type of antenna

Answer 16

A directional antenna

Question 17

How is the AC of the engine driven generator changed to DC?

Answer 17

With the Transformer rectifier unit (TRU)

Question 18

Fill in the blanks:

The carrier wave is _______ by the ______ and the _________ is amplified to a sufficient level for _________.

Answer 18

The carrier wave is –modulated– by the –signal wave– and the –modulated carrier wave – is amplified to a sufficient level for –transmission–.

Question 19

What is SSR mode C?

Answer 19

Mode C has an additional capability of automatic altitude reporting over the mode A system.

Question 20

What is SSR mode S?

Answer 20

Mode S is capable of automatic addressing of an individual aircraft and data link between aircraft and SSR stations