Re: Propagation 101

[Rob Landry <umar@nerodia.wcrb.com>]

As I understand it, the standard definitions of the various frequency
bands are:

VLF (very low frequency): 			3 kHz to 30 kHz
LF  (low frequency, long wave):			30 kHz to 300 kHz
MF  (medium frequency, medium wave):		300 kHz to 3,000 kHz
HF  (high frequency, short wave):		3 MHz to 30 MHz
VHF (very high frequency, ultra short wave):	30 MHz to 300 MHz
UHF (ultra high frequency):			300 MHz to 3,000 MHz
SHF (super high frequency):			3 GHz to 30 GHz
EHF (extremely high frequency):			30 GHz to 300 GHz

VLF is used by the U.S. Navy for slow-speed one-way transmissions to
submerged submarines.

LF is a broadcast medium in Europe, the Middle East, and the former Union
of Soviet Socialist Republics. Some people in the United States DX this
band. The FCC allows unlicensed transmissions in the band 160 - 190 KHz,
but transmitter power is limited to 1 watt.

MF includes the standard broadcast band (535 - 1,705 kHz) and the
120-meter "tropical" broadcast band (2,300- 2,500 kHz).

HF includes the 90-, 75-, and 60-meter "tropical" broadcast bands and the
49-, 41-, 31-, 25-, 22-, 19-, 16-, 15-, 13-, and 11-meter shortwave
broadcast bands.

VHF includes TV channels 2 - 6, the FM broadcast band, and TV channels 7 -
13. In some European countries digital audio radio (DAR, also called
digital audio broadcasting or DAB) is transmitted on VHF using the
Eureka-147 system.

UHF includes TV channels 14 - 69, the 950-MHz aural STL band used by radio
broadcasters, and the L- and S-band frequencies proposed for digital audio
radio (DAR) and digital audio radio satellite (DARS) services in various
countries. The FCC allows a wide variety of unliensed transmissions in the
band 902 - 928 MHz.

SHF includes most satellite TV channels and satellite radio network feeds.

EHF is sparsely utilized; atmospheric absorbtion in this band is very
high.

Communications on frequencies above 300 GHz are not regulated by the FCC. 


Rob Landry
umar@nerodia.wcrb.com

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