I20 - Radio propagation basics

The three main layers of the ionosphere that influence radio wave are the
1. A, B and C layers
2. B, C and D layers
3. C,D and E layers
4. D, E and F layers
The main cause of ionisation in the ionosphere are
1. Infra-red waves from the sun
2. Ultra-violet waves from the sun
3. X-rays from the sun
4. Gamma radiation from the sun
Which of these has the least effect on ionisation of the ionosphere
1. The power of the transmitting station
2. The time of day
3. The month of the year
4. The 11 year sun spot cycle
Which layer of the ionosphere is most important for reflecting HF signals?
1. The C layer
2. The D layer
3. The E layer
4. The F layer
The dead zone is
1. The distance between the two stations in contact
2. The distance between the end of the ground wave for each station in contact
3. The area beyond the skip zone
4. The frequency above which no signal is audible
Which layer is invovled in ionospheric ducting
1. Tropospheric layer
2. D layer
3. E layer
4. F layer
What type of conditions are likely to increase tropospheric ducting?
1. Increase in wind
2. Increase in pressure
3. Decrease in wind
4. Decrease in pressure
Which of these is least likely to attenuate signals at UHF and above?
1. Snow
2. Rain
3. Hail stones
4. Fog
What is the frequency of a signal with a wavelength of 30metres. (velocity of radio waves = 3 x 10⁸ m/sec
1. 1kHz
2. 1MHz
3. 100MHz
4. 10MHz
What is the wavelength of a signal with a frequency of 60 metres
1. 18MHz
2. 5MHz
3. 20MHz
4. 180MHz