Frequency values were divided into certain bands according to their characters and usage.r.
|
DEFINITION |
ABBREVIATION
|
FREQUENCY
|
WAVELENGTH
|
|
Very Low Frequency |
VLF |
3 kHz-30 kHz |
100 km-10 km |
|
Low Frequency |
LF |
3O kHz-300 kHz |
10km-1 km |
|
Mediurn Frequency |
MF |
300 kHz-3 MHz |
1 km-l00m |
|
High Frequency |
HF |
3 MHz-3O MHz |
100 m-10 m |
|
Very High Frequency |
VHF |
30 MHz-3O0 MHz |
10 m-1 m |
|
Ultra High Frequency |
UHF |
300 MHz-3 MHz |
100cm-10cm |
|
Super High Frequency |
SHF |
3 GHz-30 GHz |
10cm-1 cm |
|
Extremely High Frequency |
EHF |
30 GHz-300 GHz |
1 cm-1 mm |
Properties of Frequency Bands
VLF
PUBLICATION: Earth and sky waves
RANGE: Ground waves are dominant and can reach distances farther than 4000 NM. Mountains do not interfere with the propagation of low frequency waves
ANTENNA: Antenna dimensions are quite large (depending on long wavelength)
POWER: In the ranks of kW depending on the weakening of the ground waves.
USAGE: OMEGA, commercial telegraph shots, radio broadcasts
NOISE: They are highly affected by static noise and weather conditions of the air.
LF
PUBLICATION: Earth and sky waves (sky waves only dominate at night)
RANGE: 1 500 NM with ground waves, 3000 NM with sky waves
ANTENNA: 50 m. wide dipole in neck
POWER: Within the range of several kW depending on the range
USAGE: NDB, LORAN
NOISE: High enough, sensitive to weather conditions
MF
PUBLICATION: Earth and sky waves in general, direct waves in some places
RANGE: 300 NM above ground, 1000 NM above water
ANTENNA: A few meters of dipole
POWER: At the order of several hundred watts
USAGE: NDB, LORAN, ground to ground or rarely air to ground communication
NOISE: High, Fading event
HF
PUBLICATION: Generally, sky and direct waves are dominant. It can be seen in ground waves up to 100 NM.
RANGE: Silent zone between 300 NM during the day and 100 NM up to 150 NM during the night by means of sky waves.
ANTENNA: Medium-sized dipole
POWER: 100-200 W depending on the range
USAGE: Long range to ground and air to ground communication
NOISE: Moderate
VHF
PUBLICATION: Direct waves
RANGE: 100-300 NM, related to altitude receiving
ANTENNA: 1 m dipole
POWER: Within the range of several 10 W
USAGE: VOR, ILS Localiser, Markers, VDF, FM radio and television broadcasting, wireless communication.
NOISE: Minimum
UHF
PUBLICATION: Direct waves
RANGE: More than 200 NM, depending on altitude
ANTENNA: 20-30 cm. in size
POWER: A few watts
USAGE: DME, ILS Glide Path, TACAN, military communication, GPS
NOISE: At negligible levels
SHF and EHF
PUBLICATION: Direct waves
RANGE: More than 200 NM, depending on altitude
ANTENNA: A few centimeters in size
POWER: At the order of several watts
USAGE: MLS, Radio altimeter, all radar systems
NOISE: At negligible levels.
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