THE
PILOT
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ATPL
STUDENT
pilot
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all info you need to pass atpl exams
, BASIC RADIO PROPAGATION THEORY
BASIC PRINCIPLES
PROPAGATION SPEED
• Speed at which RF energy radiates through space.
• Varies depending on the electrical nature of the medium through which it travels.
• Constant value assumed: 300 000 000m/s; 300 000km/s; 162 000NM/s.
SPEED OF A RADIO WAVE:
Ø 162 000 NM/s
Ø 300 000 Km/h
RADIO WAVES SPEED:
Ø Speed of light.
CYCLE: sequence of events in which the RF energy goes from 0 to maximum positive, to 0, to maximum negative
and returns to 0.
Ø Cycle: a complete series of values of a periodical process.
FREQUENCY: Number of complete cycles/second.
• 1 Hz = 1 cycle/sec
• Nº of complete waveforms passing a given spot in 1 second.
FREQUENCY (HZ) = PROPAGATION SPEED (M/S) / WAVELENGTH (M)
1KHz = 1 000Hz
1MHz = 1 000 000Hz
1GHz = 1 000 000 000Hz
1GHz = 1000MHz = 1 000 000kHz = 1 000 000 000Hz
Ø Frequency: nº of cycles in 1 second in a radio wave expressed in Hertz (Hz)
Ø Hertz: Number of oscillations per second of an electromagnetic wave.
Ø Freq. wavelength of 1cm: 300 000 000/0,01m = 30 000 000 000Hz = 30 000 000kHz = 30 000Mz = 30GHz
Ø Frequency of a 3km wavelength: 300 000 000 = 100 000Hz = 100kHz
Ø Frequency of a 12cm wavelength: 300 000 ,12 = 2 500 000 000Hz = 2 500MHz
Ø Frequency of a 200m wavelength: 300 000 = 1 500 000Hz = 1.5MHz
Ø Frequency of a 8.25m wavelength: 300 000 ,25m = 36 363 636Hz = 36,36MHz
WAVELENGTH
• Distance it takes to complete one full cycle.
• Inversely proportional to the frequency: + frequency >> - wavelength
Ø Distance travelled by a radio wave during one cycle of transmission.
= ThePilot = 1
, WAVELENGTH (M) = PROPAGATION SPEED (M/S) / FREQUENCY (HZ)
Ø Wavelength of an NDB transmitting on 375kHz: 800m
• Propagation speed = 300 000 000m (constant)
• 375kHz = 375 000Hz
• WL = 300 000 000m/s / 375 000Hz = 800m
Ø Wavelength of a radio signal transmitted at the frequency of 75MHz: 4m
• 75MHz = 75 000 000Hz
• WL = 300 000 000 000 = 4m
Ø Wavelength with a frequency of 400kHz: 750m
• 400kHz = 400 000Hz
• WL = 300 000 000 = 750m
Ø Wavelength with a frequency of 117.95kHz: 2,54m
• 117.95kHz = 117 950 000Hz
• WL = 300 000 000/ 117 950 000 = 2,54m
Ø Wavelength with a frequency of 427kHz: 702,57m
• 427kHz = 427 000Hz
• WL = 300 000 000 = 702,57m
Ø Wavelength with a frequency of 118.7MHz: 2,53m
• 118.7MHz = 118 700 000Hz
• WL = 300 000 700 000 = 2,53m
Ø Wavelength with a frequency of 300kHz: 1000m
• 300kHz = 300 000Hz
• WL = 300 000 000 = 1000m
Ø Wavelength with a frequency of 3GHz:
• 3GHz = 3 000 000 000Hz
• WL = 300 000 000 000 000 = 0,1m = 10 cm
Ø Wavelength with a frequency of 121.95MHz: 2,46m
• 121 950 000Hz
• WL = 300 000 950 000 = 2,46m
= ThePilot = 2
, PERIOD:
• Duration of 1 cycle, in seconds.
PHASE:
Ø Fraction of 1 wavelength expressed in degrees from 000º to 360º.
PHASE DIffERENCE:
Ø Angular difference between the corresponding point of 2 cycles of equal wavelength, which is
measurable in degrees.
AMPLITUDE:
Ø Magnitude of the difference between the variable’s extreme values (max and min peak) Maximum
deflection.
BANDWIDTH:
• Total width/spread of the range/band of frequencies that an
electronic signal uses on a given transmission medium.
• Is the difference between the upper and lower cutoff frequencies.
• Unit: Hertz
• In the image: BW = 2kHz.
CARRIER FREQUENCY:
• Is the basic frequency on which radio transmits.
FREQUENCY SPACING:
• Since carrier frequencies are not absolutely stable and can vary from their value, a “buffer spacing” must
be applied between adjacent channels in order to avoid interferences.
• Ex: 25kHz radios have a wider buffer between adjacent frequencies than 8.33kHz radios.
= ThePilot = 3
PILOT
radio
navigation
ATPL
STUDENT
pilot
resume Extended
all info you need to pass atpl exams
, BASIC RADIO PROPAGATION THEORY
BASIC PRINCIPLES
PROPAGATION SPEED
• Speed at which RF energy radiates through space.
• Varies depending on the electrical nature of the medium through which it travels.
• Constant value assumed: 300 000 000m/s; 300 000km/s; 162 000NM/s.
SPEED OF A RADIO WAVE:
Ø 162 000 NM/s
Ø 300 000 Km/h
RADIO WAVES SPEED:
Ø Speed of light.
CYCLE: sequence of events in which the RF energy goes from 0 to maximum positive, to 0, to maximum negative
and returns to 0.
Ø Cycle: a complete series of values of a periodical process.
FREQUENCY: Number of complete cycles/second.
• 1 Hz = 1 cycle/sec
• Nº of complete waveforms passing a given spot in 1 second.
FREQUENCY (HZ) = PROPAGATION SPEED (M/S) / WAVELENGTH (M)
1KHz = 1 000Hz
1MHz = 1 000 000Hz
1GHz = 1 000 000 000Hz
1GHz = 1000MHz = 1 000 000kHz = 1 000 000 000Hz
Ø Frequency: nº of cycles in 1 second in a radio wave expressed in Hertz (Hz)
Ø Hertz: Number of oscillations per second of an electromagnetic wave.
Ø Freq. wavelength of 1cm: 300 000 000/0,01m = 30 000 000 000Hz = 30 000 000kHz = 30 000Mz = 30GHz
Ø Frequency of a 3km wavelength: 300 000 000 = 100 000Hz = 100kHz
Ø Frequency of a 12cm wavelength: 300 000 ,12 = 2 500 000 000Hz = 2 500MHz
Ø Frequency of a 200m wavelength: 300 000 = 1 500 000Hz = 1.5MHz
Ø Frequency of a 8.25m wavelength: 300 000 ,25m = 36 363 636Hz = 36,36MHz
WAVELENGTH
• Distance it takes to complete one full cycle.
• Inversely proportional to the frequency: + frequency >> - wavelength
Ø Distance travelled by a radio wave during one cycle of transmission.
= ThePilot = 1
, WAVELENGTH (M) = PROPAGATION SPEED (M/S) / FREQUENCY (HZ)
Ø Wavelength of an NDB transmitting on 375kHz: 800m
• Propagation speed = 300 000 000m (constant)
• 375kHz = 375 000Hz
• WL = 300 000 000m/s / 375 000Hz = 800m
Ø Wavelength of a radio signal transmitted at the frequency of 75MHz: 4m
• 75MHz = 75 000 000Hz
• WL = 300 000 000 000 = 4m
Ø Wavelength with a frequency of 400kHz: 750m
• 400kHz = 400 000Hz
• WL = 300 000 000 = 750m
Ø Wavelength with a frequency of 117.95kHz: 2,54m
• 117.95kHz = 117 950 000Hz
• WL = 300 000 000/ 117 950 000 = 2,54m
Ø Wavelength with a frequency of 427kHz: 702,57m
• 427kHz = 427 000Hz
• WL = 300 000 000 = 702,57m
Ø Wavelength with a frequency of 118.7MHz: 2,53m
• 118.7MHz = 118 700 000Hz
• WL = 300 000 700 000 = 2,53m
Ø Wavelength with a frequency of 300kHz: 1000m
• 300kHz = 300 000Hz
• WL = 300 000 000 = 1000m
Ø Wavelength with a frequency of 3GHz:
• 3GHz = 3 000 000 000Hz
• WL = 300 000 000 000 000 = 0,1m = 10 cm
Ø Wavelength with a frequency of 121.95MHz: 2,46m
• 121 950 000Hz
• WL = 300 000 950 000 = 2,46m
= ThePilot = 2
, PERIOD:
• Duration of 1 cycle, in seconds.
PHASE:
Ø Fraction of 1 wavelength expressed in degrees from 000º to 360º.
PHASE DIffERENCE:
Ø Angular difference between the corresponding point of 2 cycles of equal wavelength, which is
measurable in degrees.
AMPLITUDE:
Ø Magnitude of the difference between the variable’s extreme values (max and min peak) Maximum
deflection.
BANDWIDTH:
• Total width/spread of the range/band of frequencies that an
electronic signal uses on a given transmission medium.
• Is the difference between the upper and lower cutoff frequencies.
• Unit: Hertz
• In the image: BW = 2kHz.
CARRIER FREQUENCY:
• Is the basic frequency on which radio transmits.
FREQUENCY SPACING:
• Since carrier frequencies are not absolutely stable and can vary from their value, a “buffer spacing” must
be applied between adjacent channels in order to avoid interferences.
• Ex: 25kHz radios have a wider buffer between adjacent frequencies than 8.33kHz radios.
= ThePilot = 3
