- 160-meter band
Just above the
mediumwave broadcast band, 160 meters is the lowest radio frequency band allocation available toamateur 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.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.Fact|date=January 2008 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.
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.
Frequency allocation
The
International Telecommunications Union allocated the frequencies from [http://life.itu.int/radioclub/rr/hfband.htm 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 - 2000kHz in the rest of the world.US Allocation Table
ee also
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Shortwave bands External links
*cite web | title = ARRLWeb: US Amateur Bands | work = | url = http://www.arrl.org/FandES/field/regulations/bands.html | accessmonthday = August 3 | accessyear = 2005
*cite web | title = ARRLWeb: ARRL Band Plans | work = | url = http://www.arrl.org/FandES/field/regulations/bandplan.html | accessmonthday = August 3 | accessyear = 2005
*cite web | title = RAC Web: Canada HF Band Plan | work = | url = http://www.rac.ca/service/RAC_Draft_HF_Band_PlanR1.pdf | accessmonthday = June 27 | accessyear = 2007
*cite web | title = Ham Radio QRP | work = | url = http://www.ac6v.com/qrp.htm#CALL | accessmonthday = August 3 | accessyear = 2005
*cite web | title = UK Amateur Radio Band Plans | work = | url = http://www.rsgb.org/spectrumforum/bandplans/RSGB%20Band%20Plan%20master.htm | accessdate = January 01 | accessyear = 2007 Click the 160 Meter button at the bottom of the page
*cite web | title = ITU Frequency Allocations: HF Amateur Bands | work = | url = http://life.itu.int/radioclub/rr/hfband.htm | accessdate = January 01 | accessyear = 2008
*cite web | title = IARU Region 1 Bandplan | work = | url = http://www.iaru-r2.org/wp-content/uploads/region-1-hf-bandplan-2006.pdf | accessdate = January 01 | accessyear = 2006
*cite web | title = IARU Region 2 Bandplan | work = | url = http://www.iaru-r2.org/wp-content/uploads/region-2-mf-hf-bandplan-e.pdf | accessdate = January 01 | accessyear = 2008
*cite web | title = IARU Region 3 Bandplan | work = | url = http://www.jarl.or.jp/iaru-r3/r3bandplan.doc | accessdate = August 03 | accessyear = 2005
*cite web | title = Japan Bandplan | work = | url = http://www.jarl.or.jp/English/6_Band_Plan/JAbandplan.pdf | accessdate = April 28 | accessyear = 2008
*cite web | title = KN4LF 160 Meter Propagation Theory Notes | work= A website dedicated to layman level explanations of "seemingly" mysterious 160 Meter (MF/HF) propagation occurrences | url = http://www.kn4lf.com/kn4lf8.htm | accessdate = | accessyear =
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