6-meter band

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The 6-meter band is a portion of the VHF radio spectrum allocated to amateur radio use. Although located in the lower portion of the VHF band, it nonetheless occasionally displays propagation mechanisms characteristic of the HF bands. This normally occurs close to sunspot maximum, when solar activity increases ionization levels in the upper atmosphere. During the last sunspot peak of 2005, worldwide 6-meter propagation occurred making 6-meter communications as good as or in some instances and locations, better than HF frequencies. The prevalence of HF characteristics on this VHF band has inspired amateur operators to dub it the "magic band".

In the northern hemisphere, activity peaks from May through early August, when regular sporadic E propagation enables long-distance contacts spanning up to 2,500 kilometres (1,600 mi) for single-hop propagation. Multiple-hop sporadic E propagation allows intercontinental communications at distances of up to 10,000 kilometres (6,200 mi). In the southern hemisphere, sporadic E propagation is most common from November through early February.

History[edit]

Amateur radio[edit]

  • The Radio Regulations of the International Telecommunication Union allow amateur radio operations in the frequency range from 50.000 to 54.000 MHz.

Frequency allocations[edit]

6-meter frequency allocations for amateur radio are not universal worldwide. In the United States and Canada, the band ranges from 50 MHz to 54 MHz. In some other countries, the band is restricted to military communications. Further, in some nations, the frequency range is used for television transmissions, although most countries have assigned those television channels to higher frequencies (see channel 1).

Although the International Telecommunication Union does not allocate 6-meter frequencies to amateurs in Europe, the decline of VHF television broadcasts and commercial pressure on the lower VHF spectrum has allowed most European countries to provide a 6-meter amateur allocation.

In the United Kingdom, it is legal to use the 6-meter band between frequencies 50 MHz to 52 MHz, with some limitations at some frequencies. In the UK, 50 MHz to 51 MHz is primary usage and the rest is secondary with power limitations. A detailed bandplan can be obtained from the Radio Society of Great Britain (RSGB) website.[1]

Many organizations promote regular competitions in this frequency to promote its use and to familiarize operators to its quirks. For example RSGB VHF Contest Committee[2] has a large number of contests on 6 meters every year.[3]

Because of its peculiarity, there are a number of 6-meter band operator groups. These people monitor the status of the band between different paths and promote 6-meter band operations.

For a full list of countries using 6-meters refer to the bandplan of the International Amateur Radio Union.[4]

Television interference[edit]

Because the 6 meter band is just below the frequencies allocated to the old VHF television Channel 2 in North America (54-60 MHz), television interference (TVI) to neighbors' sets was a common problem for amateurs operating in this band prior to June 2009, when VHF TV transmissions ended in the U.S.

Equipment[edit]

A Gonset Communicator II 6-meter AM transceiver. This vacuum tube radio with a magic eye tube tuning indicator, was affectionately known as a "Gooney Box" and was popular in the 1950s and 60s. A 2-meter version was also sold.

Over the past decade or so, the availability of transceivers that include the 6-meter band has increased greatly. Many commercial HF transceivers now include the 6-meter band, as do some handheld VHF/UHF transceivers. There are also a number of stand-alone 6-meter band transceivers, although commercial production of these has been relatively rare in recent years. Despite support in more available radios, however, the 6-meter band does not share the popularity of amateur radio's 2-meter band. This is due, in large part, to the larger size of 6-meter antennas, power limitations in some countries outside the United States, and the 6-meter band's greater susceptibility to local electrical interference.

As transceivers have become more available for the 6-meter band, it has quickly gained popularity. In many countries, including the United States, access is granted to entry-level license holders. Those without access to international HF frequencies often gain their first taste of true long-distance communications on the 6-meter band. Many of these operators develop a real affection for the challenge of the band, and often continue to devote much time to it, even when they gain access to the HF frequencies after upgrading their licenses.

Common uses[edit]

Radio control[edit]

North American
Ham Band
RC channels
Ch Frequency
00 50.80 MHz
01 50.82 MHz
02 50.84 MHz
03 50.86 MHz
04 50.88 MHz
05 50.90 MHz
06 50.92 MHz
07 50.94 MHz
08 50.96 MHz
09 50.98 MHz[5]
(not used in Canada)

In North America, especially in the United States[6] and Canada,[7] the 6-meter band may be used by licensed amateurs for the safe operation of radio-controlled (RC) aircraft and other types of RC hobby miniatures. By general agreement among the amateur radio community, 200 kHz of the 6-meter band is reserved for the telecommand of models, by licensed amateurs using amateur frequencies. The sub-band reserved for this use is 50.79 MHz to 50.99 MHz with ten "specified" frequencies, numbered "00" to "09" spaced at 20 kHz apart from 50.800 to 50.980 MHz. The upper end of the band, starting at 53.0 MHz, and going upwards in 100 kHz steps to 53.8 MHz, used to be similarly reserved for RC modelers, but with the rise of amateur repeater stations operating above 53 MHz in the United States, and very few 53 MHz RC units in Canada, the move to the lower end of the 6-meter spectrum for radio-controlled model flying activities by Hams was undertaken in North America, starting in the early 1980s, and more-or-less completed by 1991. It is still completely legal for ground-level RC model operation (cars, boats, etc.) to be accomplished on any frequency within the band, above 50.1 MHz, by any licensed amateur operator in the United States; however, an indiscriminate choice of frequencies for RC operations is discouraged by the amateur radio community.

Similar provisions to those for six-meter usage in the United States and Canada for Ham-license holding aeromodelers exist on the 70-centimeter band in Europe, for amateur radio-licensed aeromodelers in Germany[8] and Switzerland.[9]

References[edit]

  1. ^ "Band Plans". Archived from the original on 2011-07-07. Retrieved 28 May 2013. 
  2. ^ "RSGB Contest Committee". Retrieved 28 May 2013. 
  3. ^ "Radio Society of Great Britain VHF Contests Committee". Archived from the original on 2006-06-27. Retrieved 28 May 2013. 
  4. ^ "IARU REGIONS". Retrieved 28 May 2013. 
  5. ^ "MAAC Canadian Frequency Chart". Model Aeronautics Association of Canada. MAAC. Retrieved July 13, 2013. 
  6. ^ "Frequency Chart for Model Operation". Retrieved 28 May 2013. 
  7. ^ "Canadian Frequency Chart". Retrieved 28 May 2013. 
  8. ^ "United Kingdom Radio Control Council: International Frequencies - Germany". UKRCC. UKRCC. Retrieved July 13, 2013. 
  9. ^ "United Kingdom Radio Control Council: International Frequencies - Switzerland". UKRCC. UKRCC. Retrieved July 13, 2013. 

Further Reading[edit]

External links[edit]

Propagation sites[edit]

Clubs and groups[edit]