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Frequency Spectrum

Introduction

The Federal Communications Commission (FCC) regulates frequency use by setting specifications for transmit frequency, power, bandwidth, modulation, and location, to name a few, and requires a license for many uses. The FCC does NOT cover the CALIBRATION of radar units, radar ACCURACY, or OPERATOR capability requirements.

Note the following multiplier abbreviations for frequency (also see appendix B -- Electromagnetic Waves).

Table A-1 -- Frequency Multipliers

Hz (hertz) cycles per second 1 Hz
kHz (kilohertz) one thousand hertz 1,000 Hz
MHz (megahertz) one million hertz 1,000,000 Hz
GHz (gigahertz) one billion hertz 1,000,000,000 Hz
THz (terahertz) one trillion hertz 1,000,000,000,000 Hz

Traffic Radar Frequencies

Table A-2 -- Traffic Radar Frequency Bands

Band Frequency Wavelength Notes
S 2.455 GHz 4.8 in
12 cm		 obsolete
X* 9.41 GHz 1.25 in
3.2 cm		 some European countries
X* 9.90 GHz 1.2 in
3.0 cm		 some European countries
X 10.525 GHz ±25 MHz 1.1 in
2.8 cm		 one 50 MHz channel
Ku* 13.450 GHz 0.88 in
2.2 cm		 some European countries
K 24.125 GHz ±100 MHz 0.49 in
1.2 cm		 one 200 MHz channel
Europe and some US systems
K 24.150 GHz ±100 MHz 0.49 in
1.2 cm		 one 200 MHz channel
Ka 33.4 - 36.0 GHz 0.35 - 0.33 in
9 - 8.3 mm		 13 channels; 200 MHz/ch
IR -- Infrared 332 THz 904 nm Laser Radar (Chapter 6)

* Not used in USA.

Table A-3 -- Select Ka Band Traffic Radar Frequencies
Frequency tolerance for Ka band radars typically ±100 MHz.

Frequency System
33.3 GHz Genesis II
33.4 GHz photo radar
33.8 GHz BEE 36
34.3 GHz TMT-6F photo radar
Multanova 6F photo radar
34.6 GHz PR-100 photo radar
34.70 or 34.94 GHz Stalker ATR
34.2 - 35.2 GHz Stalker ATR (freq hopper)

Figure A-1 -- Select Ka Band Radars

Fig A-1

Frequency Band Designations

Military Radar Bands
Military radar band nomenclature (L, S, C, X, Ku, K and Ka bands) originated during World War II as a secret code so scientists and engineers could talk about frequencies without divulging them. After the war the codes were declassified and millimeter (mm) was added. A form of the designations was eventually adopted and later dropped (considered obsolete) by the IEEE -- Institute of Electric and Electronic Engineers. Military radar band nomenclature is widely used today in radar, satellite and terrestrial communications, and electronic countermeasure applications, both military and commercial.

Table A-4 -- Military Radar Bands

Radar Band Frequency Notes
HF 3 - 30 MHz High Frequency
VHF 30 - 300 MHz Very High Frequency
UHF 300 - 1000 MHz Ultra High Frequency
L 1 - 2 GHz
S 2 - 4 GHz
C 4 - 8 GHz
X 8 - 12 GHz
Ku 12 - 18 GHz
K 18 - 27 GHz
Ka 27 - 40 GHz
mm 40 - 300 GHz millimeter wavelength
mm sub-bands
Q 40 - 60 GHz Universal Designation
W 60 - 95 GHz Universal Designation
V 50 - 70 GHz Microwave Designation

Military HF, VHF, UHF same as Radio Band HF, VHF, UHF respectively.

ITU Radar Bands
The International Telecommunications Union (ITU) specifies bands designated for radar systems as described in the table below. The ITU bands are sub-bands of military designations.

Table A-5 -- International Telecommunications Union Radar Bands

ITU Band Frequency
VHF 138 - 144 MHz
216 - 225 MHz
UHF 420 - 450 MHz
890 - 942 MHz
L 1.215 - 1.400 GHz
S 2.3 - 2.5 GHz
2.7 - 3.7 GHz
C 5.250 - 5.925 GHz
X 8.500 - 10.680 GHz
Ku 13.4 - 14.0 GHz
15.7 - 17.7 GHz
K 24.05 - 24.25 GHz
Ka 33.4 - 36.0 GHz

VHF -- Very High Frequency
UHF -- Ultra High Frequency

Radio Bands
Radio band designations are summarized below. Note that the radio band chart includes wavelength. In the early days of radio it was easier to measure wavelength than frequency.

Table A-6 -- Radio Frequency Bands

Band Nomenclature Frequency Wavelength
ELF Extremely Low Frequency 3 - 30 Hz 100,000 - 10,000 km
SLF Super Low Frequency 30 - 300 Hz 10,000 - 1,000 km
ULF Ultra Low Frequency 300 - 3000 Hz 1,000 - 100 km
VLF Very Low Frequency 3 - 30 kHz 100 - 10 km
LF Low Frequency 30 - 300 kHz 10 - 1 km
MF Medium Frequency 300 - 3000 kHz 1 km - 100 m
HF High Frequency 3 - 30 MHz 100 - 10 m
VHF Very High Frequency 30 - 300 MHz 10 - 1 m
UHF Ultra High Frequency 300 - 3000 MHz 1 m - 10 cm
SHF Super High Frequency 3 - 30 GHz 10 - 1 cm
EHF Extremely High Frequency 30 - 300 GHz 1 cm - 1 mm

ECM Bands
The electronic countermeasures (ECM) industry occasionally refers to band designations as described below.

Table A-7 -- ECM Bands

Band Frequency
A 30 - 250 MHz
B 250 - 500 MHz
C 500 - 1,000 MHz
D 1 - 2 GHz
E 2 - 3 GHz
F 3 - 4 GHz
G 4 - 6 GHz
H 6 - 8 GHz
I 8 - 10 GHz
J 10 - 20 GHz
K 20 - 40 GHz
L 40 - 60 GHz
M 60 - 100 GHz

Sound Waves
Sound waves are really air pressure waves (not electromagnetic like radio/radar) resulting from vibrating air molecules. Sound does not exist in outer space (vacuum). Most humans can hear air pressure waves (sound) between about 20 Hz and 20,000 Hz, the audio band. Below 20 Hz is the infrasound band, 20 kHz - 10 MHz is the ultrasound band.

Table A-8
Sound Bands

Band -- Frequency Range --
infrasound 0 - 20 Hz
audio 20 - 20,000 Hz
ultrasound 20 kHz - 10 MHz

Pressure waves (sound) can extend as high as about 10 MHz, however above about 160 kHz sound propagation range greatly decreases due to excessive air absorption.

Table A-8a
Sound Applications1

Frequency Range Use Band
0 - 20 Hz Elephants, Whales infrasound
20 - 20,000 Hz Humans, Animals, Fish, SONAR audio
10 - 30 kHz Rodents audio - ultrasound
20 Hz - 75 kHz Insects audio - ultrasound
20 - 160 kHz Bats, Dolphins ultrasound
100 kHz - 2 MHz Structures Test ultrasound
1 - 10 MHz Medical Applications ultrasound

1 -- Data from Monitoring Times magazine, Monitoring Ultrasound, Phil Anderson W0XI, April 2009, p68

Police Traffic Radar Handbook
Appendix A -- Frequency Spectrum

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