160 meters
Encyclopedia
Just above the mediumwave
broadcast band
, 160 meters is the lowest radio frequency band allocation available to amateur radio
operators in most countries. Seasoned operators often refer to 160 meters as the Top Band. It is also sometimes referred to as the "Gentleman's Band" in contrast to the often-freewheeling 80
and 20
meter band activity.
The 1947 International Radio Conference of Atlantic City reduced the allocation to 1800-2000 kc under the provision that amateurs must not interfere with Loran operation.
As the high frequency bands were developed in mid 1920s — along with their smaller, more convenient antennas — 160 meters fell in to a period of relative nonuse. Although there has always been activity on the band, fewer and fewer hams are willing to put up the antennas necessary to take advantage of the band's unique properties. For most amateurs, the HF bands are much easier to use and HF antennas need a lot less real estate.
After World War II, the 160 meter band was apparently not coming back. A large part of the U.S. 160 meter band was allocated on a primary basis to the LORAN
radio-navigation system that began operating in and around the 160 meter band in 1942. Amateurs were relegated to secondary, non-interfering status, with severe regional power limitations and restricted day/night operations on just a few narrow segments of the band.
Many older hams recall, with no great fondness, the ear-shattering buzz-saw racket of high power LORAN stations that began in 1942 until LORAN-A was phased out in North America on December 31, 1980 and most of the world by 1985. LORAN-A was still operating in China and Japan in 1995.
Great ingenuity was used to eliminate the pulse noise of the powerful LORAN-A transmitters through such famous circuitry as the "Select-O-Ject" of the late 1950s. The technology was adapted to modern noise blanking circuits used in current amateur receivers and transceivers.
Despite many obstacles and threats from commercial and military spectrum users, the efforts of a small number of determined 160 meter operators enabled the band to survive. The band experienced a rebirth with the demise of LORAN-A in the United States in December, 1980 and the removal of power restrictions below 1900 kHz soon thereafter. Power restrictions above 1900 kHz were removed in March 1984. 160 meters was then no longer regarded as the "orphan" band as it had been for more than half a century.
(on the order of a quarter-wavelength
or more), are difficult to erect for many amateurs with limited space. Nevertheless, many radio amateurs successfully communicate over very long distances with relatively small antennas. 160 meters is populated by many highly dedicated experimenters, as it is a proving ground for ingenuity in antenna design and operating technique.
Much about ionospheric
and propagation
on 160 meters is still not completely understood. Phenomena such as "chordal hop" propagation are frequently observed, as well as other unexplained long-distance propagation mechanisms. Inexplicable radio blackouts — sometimes encountered on the AM broadcast band — also occur on 160 meters. Many of these phenomena have been investigated in the scientific community, while 160 meter operators continue to be in a unique position to further investigate such fascinating mysteries. The original "magic of radio" is very much alive and well on 160 meters.
Mediumwave
Medium wave is the part of the medium frequency radio band used mainly for AM radio broadcasting. For Europe the MW band ranges from 526.5 kHz to 1606.5 kHz...
broadcast band
AM broadcasting
AM broadcasting is the process of radio broadcasting using amplitude modulation. AM was the first method of impressing sound on a radio signal and is still widely used today. Commercial and public AM broadcasting is carried out in the medium wave band world wide, and on long wave and short wave...
, 160 meters is the lowest radio frequency band allocation available to amateur radio
Amateur radio
Amateur radio is the use of designated radio frequency spectrum for purposes of private recreation, non-commercial exchange of messages, wireless experimentation, self-training, and emergency communication...
operators in most countries. Seasoned operators often refer to 160 meters as the Top Band. It is also sometimes referred to as the "Gentleman's Band" in contrast to the often-freewheeling 80
80 meters
The 80 meter or 3.5 MHz band is a core amateur radio frequency band, allocated frequencies from 3.5 to 4.0 MHz in IARU Region 2, and generally 3.5 to 3.8 or 3.9 MHz in Regions 1 and 3 respectively. The portion of the band used for phone communications is sometimes referred to as 75 meters...
and 20
20 meters
The 20-meter or 14-MHz amateur radio band is a portion of the shortwave radio spectrum, comprising frequencies stretching from 14.000 MHz to 14.350 MHz. The 20-meter band was first made available to amateurs in the United States by the Third National Radio Conference on October 10, 1924...
meter band activity.
History
The 160 meter band is the oldest amateur band and was the staple of reliable communication in the earliest days of amateur radio, when almost all communications were over relatively short distances. The band was allocated on a worldwide basis by the International Radiotelegraph Conference in Washington, D.C., on October 4, 1927. The allocation was 1715–2000 kHz.The 1947 International Radio Conference of Atlantic City reduced the allocation to 1800-2000 kc under the provision that amateurs must not interfere with Loran operation.
As the high frequency bands were developed in mid 1920s — along with their smaller, more convenient antennas — 160 meters fell in to a period of relative nonuse. Although there has always been activity on the band, fewer and fewer hams are willing to put up the antennas necessary to take advantage of the band's unique properties. For most amateurs, the HF bands are much easier to use and HF antennas need a lot less real estate.
After World War II, the 160 meter band was apparently not coming back. A large part of the U.S. 160 meter band was allocated on a primary basis to the LORAN
LORAN
LORAN is a terrestrial radio navigation system using low frequency radio transmitters in multiple deployment to determine the location and speed of the receiver....
radio-navigation system that began operating in and around the 160 meter band in 1942. Amateurs were relegated to secondary, non-interfering status, with severe regional power limitations and restricted day/night operations on just a few narrow segments of the band.
Many older hams recall, with no great fondness, the ear-shattering buzz-saw racket of high power LORAN stations that began in 1942 until LORAN-A was phased out in North America on December 31, 1980 and most of the world by 1985. LORAN-A was still operating in China and Japan in 1995.
Great ingenuity was used to eliminate the pulse noise of the powerful LORAN-A transmitters through such famous circuitry as the "Select-O-Ject" of the late 1950s. The technology was adapted to modern noise blanking circuits used in current amateur receivers and transceivers.
Despite many obstacles and threats from commercial and military spectrum users, the efforts of a small number of determined 160 meter operators enabled the band to survive. The band experienced a rebirth with the demise of LORAN-A in the United States in December, 1980 and the removal of power restrictions below 1900 kHz soon thereafter. Power restrictions above 1900 kHz were removed in March 1984. 160 meters was then no longer regarded as the "orphan" band as it had been for more than half a century.
Technical Characteristics
Effective 160 meter operation can be particularly challenging, as full sized antennasAntenna (radio)
An antenna is an electrical device which converts electric currents into radio waves, and vice versa. It is usually used with a radio transmitter or radio receiver...
(on the order of a quarter-wavelength
Wavelength
In physics, the wavelength of a sinusoidal wave is the spatial period of the wave—the distance over which the wave's shape repeats.It is usually determined by considering the distance between consecutive corresponding points of the same phase, such as crests, troughs, or zero crossings, and is a...
or more), are difficult to erect for many amateurs with limited space. Nevertheless, many radio amateurs successfully communicate over very long distances with relatively small antennas. 160 meters is populated by many highly dedicated experimenters, as it is a proving ground for ingenuity in antenna design and operating technique.
Much about ionospheric
Ionosphere
The ionosphere is a part of the upper atmosphere, comprising portions of the mesosphere, thermosphere and exosphere, distinguished because it is ionized by solar radiation. It plays an important part in atmospheric electricity and forms the inner edge of the magnetosphere...
and propagation
Wave propagation
Wave propagation is any of the ways in which waves travel.With respect to the direction of the oscillation relative to the propagation direction, we can distinguish between longitudinal wave and transverse waves....
on 160 meters is still not completely understood. Phenomena such as "chordal hop" propagation are frequently observed, as well as other unexplained long-distance propagation mechanisms. Inexplicable radio blackouts — sometimes encountered on the AM broadcast band — also occur on 160 meters. Many of these phenomena have been investigated in the scientific community, while 160 meter operators continue to be in a unique position to further investigate such fascinating mysteries. The original "magic of radio" is very much alive and well on 160 meters.