INGENIEUR
Band Name |
Frequency Range |
Wavelength |
|
|
Range |
Notes
HF |
3 – 30 MHz |
10 – 100 m |
High Frequency ( HF ), Coastal Radar Systems , |
|
|
|
over the horizon radars . |
VHF |
30 – 300 MHz |
1 – 10 m |
Very High Frequency ( VHF ), very long range , |
|
|
|
ground penetrating . |
UHF |
300 – 1000 MHz |
0.3 – 1 m |
Ultra High Frequency ( UHF ), very long range |
|
|
|
( e . g . ballistic missile early warning ), ground |
|
|
|
penetrating , foliage penetrating . |
L |
1 – 2 GHz |
15 – 30 cm |
Long ( L ), long range air traffic control and |
|
|
|
surveillance . |
S |
2 – 4 GHz |
7.5 – 15 cm |
Moderate range surveillance , Terminal air |
|
|
|
traffic control , long range weather , marine |
|
|
|
radar ; ' S ' for ' short '. |
C |
4 – 8 GHz |
3.75 – 7.5 cm |
Compromise - C , satellite transponders , |
|
|
|
between X and S bands , weather , long range |
|
|
|
tracking . |
X |
8 – 12 GHz |
2.5 – 3.75 cm |
Missile guidance , marine radar , weather , medium resolution mapping and ground surveillance , short range tracking . Named X band because the frequency was a secret during World War 2 . |
Table 1 : Radar Frequency Bands
busy waters . These systems used X Band or S Band radars . They are electronic navigation instruments that use a rotating antenna to sweep a narrow beam of microwaves around the water surface surrounding the ship to the horizon , detecting targets by microwaves reflected from them and generating a picture of the ship ' s surroundings on a display screen . Microwaves are a form of electromagnetic radiation with wavelengths ranging from about one metre to one millimetre with frequencies between 300MHz ( 1m ) and 300 GHz ( 1mm ). Microwaves occupy a place in the electromagnetic spectrum with frequency above ordinary radio waves and below infrared light . The typical ranges for marine radars are between 22 and 72 nautical miles . Marine radars have smaller coverage compared to air traffic surveillance radars .
The X Band is the designation for a band of frequencies in the microwave radio region of the electromagnetic spectrum . The frequency range of the X Band is rather indefinitely set between approximately 7.0 to 11.2GHz . The X band is used for wireless computer networks , radar and satellite communication . The S Band is the designation for a part of the microwave band of the electromagnetic spectrum covering frequencies between 2.0 to 4.0GHz . Thus it crosses the conventional boundary between the Super High Frequency ( SHF ) and Ultra High Frequency ( UHF ) bands at 3.0GHz . It is used by airport surveillance radar for air traffic control , surface ship radar , weather radar and some communications satellites . The X Band , being of higher frequency is used for a sharper image and better resolution whereas the S Band is used especially when operating in rain or fog as well as for identification and tracking . Table 1 shows some of the radar frequency bands .
Marine radar systems operate in the high radio frequency and microwave range . Therefore , unlike X-rays and nuclear radiation , the emissions are non-ionising radiation and do not penetrate the human body but can cause heating of the surface , particularly of the skin and eyes ( cornea ).
46 VOL 83 JULY-SEPTEMBER 2020