160 meters
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This article or section deals primarily with the United States and does not represent a worldwide view of the subject. Please improve this article or discuss the issue on the talk page. |
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 Top Band, it is also sometimes referred to as the "Gentleman's Band" in comparison to the often-freewheeling 80 and 20 meter band allocations.
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[edit] 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.
As the higher frequency bands were developed in the 1920s -- along with their smaller, more convenient antennas -- 160 meters fell in to a period of relative disuse. Although there has always been activity on the band, fewer and fewer hams were willing to put up the sort of antennas necessary to take advantage of the band's unique properties. For most amateurs, the HF bands were 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 band was allocated on a primary basis to the LORAN radio-navigation system. Amateurs were relegated to secondary, non-interfering status; with regional power limitations, and day/night operating restrictions on a few narrow sections of the band.
Many older hams recall, with no great fondness, the ear-shattering buzz-saw racket of nearby LORAN stations from the mid-1940s until 1980.[citation needed] Great ingenuity was used to eliminate the pulse noise of the powerful LORAN transmitters through such famous circuitry as the "Select-O-Ject" of the late 1950s, the technology of which 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 in the United States in 1980 and the removal of power restrictions soon thereafter. 160 meters was then no longer regarded as the "orphan" band as it had been for nearly half a century.
[edit] Technical Characteristics
Effective 160 meter operation can be particularly challenging, as full sized antennas (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 propagation on 160 meters is still not completely understood. Phenomena such as "chordal hop" propagation are frequently observed, as well other unexplained long-distance propagation mechanisms. Inexplicable radio blackouts -- such as are 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.
[edit] Frequency allocation
The International Telecommunications Union allocated the frequencies from 1810 - 2000 KHz to amateur radio operations in ITU Region 1 (Europe, Greenland, Africa, the Middle East west of the Persian Gulf and including Iraq, the former Soviet Union and Mongolia) and 1800 - 2000 kHz in the rest of the world.
[edit] US Allocation Table
| US License Class | 1.800 – 2.000 |
|---|---|
| General, Advanced, Extra |
[edit] Key
| = CW, RTTY, data, phone and image |
[edit] US Band Plan
By "Gentlemen's agreement", US amateurs voluntarily limit their 160 meter emissions according to the following suggested bandplan:
| 1.800 MHz–1.830 MHz | CW, RTTY and other narrowband modes |
| 1.830 MHz–1.840 MHz | CW, RTTY and other narrowband modes, Intercontinental QSOs only |
| 1.840 MHz–1.850 MHz | CW, SSB, SSTV, other wideband modes, Intercontinental QSOs only |
| 1.850 MHz–2.000 MHz | CW, phone, SSTV and other wideband modes |
[edit] IARU Region Band Plans
| 160 Meters | 1810 1838 | 1838 1840 | 1840 1843 | 1843 2000 | |
|---|---|---|---|---|---|
| IARU Region 1 | |||||
| IARU Region 2 | 1800 - 1840 | ||||
| IARU Region 3 | 1800 - 1840 | ||||
| Note: Region 2 QRP/DX window is 1830-1850 | |||||
[edit] Key
| = CW and data (<200 Hz bandwidth) | |
| = CW, RTTY and data (< 500 Hz Bandwidth) | |
| = CW, phone and image (<3 kHz bandwidth) | |
| = CW, RTTY, data, test, phone and image |
[edit] See also
[edit] External links
- ARRLWeb: US Amateur Bands. Retrieved on August 3, 2005.
- ARRLWeb: ARRL Band Plans. Retrieved on August 3, 2005.
- RAC Web: Canada HF Band Plan. Retrieved on June 27, 2007.
- Ham Radio QRP. Retrieved on August 3, 2005.
- UK Amateur Radio Band Plans. Retrieved on January 01, 2007. Click the 160 Meter button at the bottom of the page
- ITU Frequency Allocations: HF Amateur Bands. Retrieved on January 01, 2008.
- IARU Region 1 Bandplan. Retrieved on January 01, 2006.
- IARU Region 2 Bandplan. Retrieved on January 01, 2008.
- IARU Region 3 Bandplan. Retrieved on August 03, 2005.
- Japan Bandplan. Retrieved on April 28, 2008.
- KN4LF 160 Meter Propagation Theory Notes. A website dedicated to layman level explanations of "seemingly" mysterious 160 Meter (MF/HF) propagation occurrences.
