RADIO PROPAGATION THEORY

Question 1

1. The process which causes the reduction in signal strength as range from a transmitter increases is known as:

Answer 1

attenuation

Question 2

2. Which of the following will give the greatest surface wave range?

Answer 2

500 kHz

Question 3

3. It is intended to increase the range of a VHF transmitter from 50 nm to 100 nm. This will be achieved by increasing the power output by a factor of:

Answer 3

4

Question 4

4. A 300 kHz transmitter has an output of 1600 watts, the effective range over the sea will be:

Answer 4

120 nm

Question 5

5. The maximum range an aircraft at 2500 ft can communicate with a VHF station at 196 ft is:

Answer 5

79 nm

Question 6

6. What is the minimum height for an aircraft at a range of 200 nm to be detected by a radar at 1,700 ft amsl?

Answer 6

15,000 ft

Question 7

7. Determine which of the following statements concerning atmospheric ionisation are correct:
8. The highest levels of ionisation will be experienced in low latitudes.
9. Ionisation levels increase linearly with increasing altitude.
10. The lowest levels of ionisation occur about midnight.
11. The E-layer is higher by night than by day because the ionisation levels are lower at
    night.

Answer 7

statements 1 and 4 are correct

Question 8

8. The average height of the E-layer is …… and the maximum range for skywave will be ……

Answer 8

125 km, 1350 nm

Question 9

9. Concerning HF communications, which of the following is correct?

Answer 9

The frequency required for short ranges will be less than the frequency required for long ranges