Propagation Theory Flashcards
Within the airband, what frequency range is normally used for radio navigation?
108 MHz to 117.975 MHz.
What is the frequency separation between airband channels?
25 kHz or 8.33 kHz.
In practice, what is the range of VHF radio waves proportional to?
To the power of the transmitter.
What is the main requirement for successful VHF communication?
Line of sight.
What is the frequency range of the airband?
108 MHz to 137 MHz.
What is the general formula for determining the theoretical range of VHF radio waves?
1.23 · [√(transmitter height) + √(receiver height)]
Within the airband, what frequency range is normally used for voice communication?
118 MHz to 137 MHz.
What determines the characteristics of a radio wave?
Its frequency and wavelength.
Define: ducting.
A way VHF radio waves travel when certain atmospheric layers exist. In these conditions the range of VHF radio waves may be increased beyond line of sight.
What is the only occasion when the word point should be used instead of decimal?
When discussing the 8.33 kHz spacing capability.
Define: airband.
A series of frequencies allocated exclusively to civil aviation.
Are aircraft required to be equipped with radios capable of 8.33 kHz spacing?
Not universally. It is a requirement in the upper European airspace.
Define: radio wave.
Electromagnetic wave travelling at the speed of light.
When transmitting frequencies, and assuming that the first and third decimal are not a zero, state how many decimal points should be transmitted:
(a) when channels are separated by 8.33 kHz
(b) when channels are separated by 25 kHz
(a) one or three
(b) two
