ВУЗ: Казахская Национальная Академия Искусств им. Т. Жургенова
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The Electromagnetic Spctrum 11-17
Table 11.1.6 Applications of Interest in the Microwave Band (up to 40 GHz):
Application
Frequency
Aero Navigation
0.96–1.215 GHz
GPS Down Link
1.2276 GHz
Military COM/Radar
1.35–1.40 GHz
Miscellaneous COM/Radar
1.40–1.71 GHz
L-Band Telemetry
1.435–1.535 GHz
GPS Down Link
1.57 GHz
Military COM (Troposcatter/Telemetry)
1.71–1.85 GHz
Commercial COM & Private LOS
1.85–2.20 GHz
Microwave Ovens
2.45 GHz
Commercial COM/Radar
2.45–2.69 GHz
Instructional TV
2.50–2.69 GHz
Military Radar (Airport Surveillance)
2.70–2.90 GHz
Maritime Navigation Radar
2.90–3.10 GHz
Miscellaneous Radars
2.90–3.70 GHz
Commercial C-Band SAT COM Down Link
3.70–4.20 GHz
Radar Altimeter
4.20–4.40 GHz
Military COM (Troposcatter)
4.40–4.99 GHz
Commercial Microwave Landing System
5.00–5.25 GHz
Miscellaneous Radars
5.25–5.925 GHz
C-Band Weather Radar
5.35–5.47 GHz
Commercial C-Band SAT COM Up Link
5.925–6.425 GHz
Commercial COM
6.425–7.125 GHz
Mobile TV Links
6.875–7.125 GHz
Military LOS COM
7.125–7.25 GHz
Military SAT COM Down Link
7.25–7.75 GHz
Military LOS COM
7.75–7.9 GHz
Military SAT COM Up Link
7.90–8.40 GHz
Miscellaneous Radars
8.50–10.55 GHz
Precision Approach Radar
9.00–9.20 GHz
X-Band Weather Radar (& Maritime Navigation Radar)
9.30–9.50 GHz
Police Radar
10.525 GHz
Commercial Mobile COM (LOS & ENG)
10.55–10.68 GHz
Common Carrier LOS COM
10.70–11.70 GHz
Commercial COM
10.70–13.25 GHz
Commercial Ku-Band SAT COM Down Link
11.70–12.20 GHz
DBS Down Link & Private LOS COM
12.20–12.70 GHz
ENG & LOS COM
12.75–13.25 GHz
Miscellaneous Radars & SAT COM
13.25–14.00 GHz
Commercial Ku-Band SAT COM Up Link
14.00–14.50 GHz
Military COM (LOS, Mobile, &Tactical)
14.50–15.35 GHz
Aero Navigation
15.40–15.70 GHz
Miscellaneous Radars
15.70–17.70 GHz
DBS Up Link
17.30–17.80 GHz
Common Carrier LOS COM
17.70–19.70 GHz
Commercial COM (SAT COM & LOS)
17.70–20.20 GHz
Private LOS COM
18.36–19.04 GHz
Military SAT COM
20.20–21.20 GHz
Miscellaneous COM
21.20–24.00 GHz
Police Radar
24.15 GHz
Navigation Radar
24.25–25.25 GHz
Military COM
25.25–27.50 GHz
Commercial COM
27.50–30.00 GHz
Military SAT COM
30.00–31.00 GHz
Commercial COM
31.00–31.20 GHz
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The Electromagnetic Spectrum
11-18 Broadcast Transmission Systems
Gamma Ray Band
The gamma ray band is sub-divided into the following segments:
•
Primary gamma rays, approximately 1 Kev up to 1 Mev (circa 300 pm down to 300 fm), circa
1 EHz up to 1000 EHz
•
Secondary gamma rays, approximately 1 Mev up to
∞ (300 fm down to 0 m), 1000 EHz up to
∞
Secondary gamma rays are created from collisions of high energy cosmic rays with particles in
the Earth’s upper atmosphere.
The primary gamma rays are further sub-divided into the following segments:
•
Soft gamma rays, approximately 1 Kev up to circa 300 Kev (circa 300 pm down to circa 3
pm), circa 1 EHz up to circa 100 EHz
•
Hard gamma rays, approximately 300 Kev up to 1 Mev (circa 3 pm down to 300 fm), circa
100 EHz up to 1000 EHz
Gamma rays are essentially very energetic X rays. The distinction between the two is based on
their origin. X rays are emitted during atomic processes involving energetic electrons; gamma
rays are emitted by excited nuclei or other processes involving sub-atomic particles.
Gamma rays are emitted by the nucleus of radioactive material during the process of natural
radioactive decay as a result of transitions from high energy excited states to low energy states in
atomic nuclei. Cobalt 90 is a common gamma ray source (with a half-life of 5.26 years). Gamma
rays are also produced by the interaction of high energy electrons with matter. “Cosmic” gamma
rays cannot penetrate the Earth’s atmosphere.
Applications of gamma rays are found both in medicine and in industry. In medicine, gamma
rays are used for cancer treatment, diagnoses, and prevention. Gamma ray emitting radioisotopes
are used as tracers. In industry, gamma rays are used in the inspection of castings, seams, and
welds.
11.1.3 Bibliography
Collocott, T. C., A. B. Dobson, and W. R. Chambers (eds.): Dictionary of Science & Technology.
Handbook of Physics, McGraw-Hill, New York, N.Y., 1958.
Judd, D. B., and G. Wyszecki: Color in Business, Science and Industry, 3rd ed., John Wiley and
Sons, New York, N.Y.
Kaufman, Ed: IES Illumination Handbook, Illumination Engineering Society.
Lapedes, D. N. (ed.): The McGraw-Hill Encyclopedia of Science & Technology, 2nd ed.,
McGraw-Hill, New York, N.Y.
Norgard, John: “Electromagnetic Spectrum,” NAB Engineering Handbook, 9
th
ed., Jerry C. Whi-
taker (ed.), National Association of Broadcasters, Washington, D.C., 1999.
Norgard, John: “Electromagnetic Spectrum,” The Electronics Handbook, Jerry C. Whitaker
(ed.), CRC Press, Boca Raton, Fla., 1996.
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The Electromagnetic Spectrum
The Electromagnetic Spctrum 11-19
Stemson, A: Photometry and Radiometry for Engineers, John Wiley and Sons, New York, N.Y.
The Cambridge Encyclopedia, Cambridge University Press, 1990.
The Columbia Encyclopedia, Columbia University Press, 1993.
Webster’s New World Encyclopedia, Prentice Hall, 1992.
Wyszecki, G., and W. S. Stiles: Color Science, Concepts and Methods, Quantitative Data and
Formulae, 2nd ed., John Wiley and Sons, New York, N.Y.
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The Electromagnetic Spectrum
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The Electromagnetic Spectrum
11-21
Chapter
11.2
Propagation
William Daniel, Edward W. Allen, Donald G. Fink
11.2.1 Introduction
The portion of the electromagnetic spectrum currently used for radio transmissions lies between
approximately 10 kHz and 40 GHz. The influence on radio waves of the medium through which
they propagate is frequency-dependent. The lower frequencies are greatly influenced by the char-
acteristics of the earth’s surface and the ionosphere, while the highest frequencies are greatly
affected by the atmosphere, especially rain. There are no clear-cut boundaries between frequency
ranges but instead considerable overlap in propagation modes and effects of the path medium.
In the U.S., those frequencies allocated for television-related use include the following:
•
54–72 MHz: TV channels 2–4
•
76–88 MHz: TV channels 5–6
•
174–216 MHz: TV channels 7–13
•
470–806 MHz: TV channels 14–69
•
0.9–12.2 GHz: nonexclusive TV terrestrial and satellite ancillary services
•
12.2–12.7 GHz: direct satellite broadcasting
•
12.7–40 GHz: direct satellite broadcasting
11.2.2 Propagation in Free Space
For simplicity and ease of explanation, propagation in space and under certain conditions involv-
ing simple geometry, in which the wave fronts remain coherent, may be treated as ray propaga-
tion. It. should be kept in mind that this assumption may not hold in the presence of obstructions,
surface roughness, and other conditions which are often encountered in practice.
For the simplest case of propagation in space, namely that of uniform radiation in all direc-
tions from a point source, or isotropic radiator, it is useful to consider the analogy to a point
source of light, The radiant energy passes with uniform intensity through all portions of an imag-
inary spherical surface located at a radius r from the source. The area of such a surface is 4
πr
2
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Source: Standard Handbook of Audio and Radio Engineering