# FREQUENCY SPECTRUM by ewghwehws

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```									                                               FREQUENCY SPECTRUM

Figure 1, which follows, depicts the electromagnetic radiation spectrum and some of the commonly used or known
areas. Figure 2 depicts the more common uses of the microwave spectrum. Figure 3 shows areas of the spectrum which
are frequently referred to by band designations rather than by frequency.

Section 7-1 provides an additional breakdown of the EO/IR spectrum.

To convert from frequency (f) to wavelength (8) and vice versa, recall that f = c/8, or 8 = c/f;
where c = speed of light.

3x10 8   3x105    300      0.3                               3x10 8             3x105               300                0.3
8meter '          '        '       '                  or       f Hz '            f kHz '            f MHz '            f GHz '
f Hz     f kHz   f MHz   f GHz                              8meter             8meter             8meter             8meter

Some quick rules of thumb follow:
Metric:
Wavelength in cm = 30 / frequency in GHz
For example: at 10 GHz, the wavelength = 30/10 = 3 cm
English:
Wavelength in ft = 1 / frequency in GHz
For example: at 10 GHz, the wavelength = 1/10 = 0.1 ft

2-3.1
0.3        0.4    0.5 0.6       0.8   1.0                 2          3         4      5        6        8       10                20        30          40         50 60     80    100
GHz                                                                       GHz                                                                GHz

1m                                                                  10 cm                                                                   1 cm

Figure 2. The Microwave Spectrum

FREQUENCY (MHz)                                                            FREQUENCY (GHz)
20         30               100       200     300       500                  1.5 2       3 4 5 6 8 10 15 20 30 40                          60 80 100             200 300 400
12 18 27

110

VHF                           UHF              L               S            C         X    K* K
u          K*    V       W              Millimeter
HF                                                                                                                               a
U.S. INDUSTRY STANDARD BANDS (IEEE Radar Designation)

9 (UHF)                                    10 (SHF)
7 (HF)                    8 (VHF)                                                                                                              11 (EHF)                     12
INTERNATIONAL STANDARD BANDS

250

A                           B            C         D           E       F    G       H I        J       K        L       M
MILITARY STANDARD BANDS
* "u" stands for unabsorbed or under K; "a" stands for absorption region or above K

Figure 3. Frequency Band Designations

2-3.2

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