40-meter band

The 40 meters or 7 MHz band is a core amateur radio frequency band, spanning 7000 to 7300 kilohertz, allocated to radio amateurs in all countries worldwide. The 40 meter band was made available to amateurs in the United States by the [http://earlyradiohistory.us/1924conf.htm Third National Radio Conference] on October 10th, 1924. 40 meters is considered the most reliable all-season DX band, most useful for inter-continental communication at night. It is extremely useful for short to medium distance contacts from local contacts out to a range of 500–1500 km, depending on conditions, during the day. In higher latitudes, daytime inter-continental communication is also possible in winter, for example a good path often opens between Japan and northern Europe in the hours leading up to European midday from late November until late January, with a long path opening to the west coast of the United States and Canada after midday.

For many years the portion of the band from 7100-7300 kilohertz has been allocated to short wave broadcasters outside the Americas and not available to radio amateurs outside ITU Region 2. At the World Radio Conference WRC-03 in 2003 it was agreed that the broadcast stations would move out of the section 7100-7200 kiloherz on 29 March 2009 and that portion would become a worldwide exclusive amateur allocation afterwards. Discussions on releasing the remaining 100 kHz of the band to amateurs at a later date will continue in future conferences. Several European countries have now allowed amateur communication in the 7100-7200 kilohertz section on a shared non-interference basis as an interim measure.

Due to the 24 hour nature of the band, the wide variety of ranges that can be spanned with it, and its shared nature, it tends to be extremely crowded, and interference from other amateurs and broadcasters can be a serious limiting factor. In addition, amateurs in east and south-east Asia have suffered severe interference from illegal users in recent years.

Radio propagation characteristics

This band allows both long distance communications (DX) between late afternoon and early morning hours and short distance NVIS contacts during daytime, especially during periods of high solar activity.

With its unique combination of intra- and inter-continental communications possibilities, 40 meters is considered a key band in building a winning shortwave contesting score, especially in the lower part of the sunspot cycle.

Frequency allocation

Japan

United States

Key

ee also

Shortwave bands

References

*cite web | title = ARRLWeb: US Amateur Bands | work = | url = http://www.arrl.org/FandES/field/regulations/bands.html | accessmonthday=3 August | accessyear = 2005

*cite web | title = ARRLWeb: ARRL Band Plans | work = | url = http://www.arrl.org/FandES/field/regulations/bandplan.html | accessmonthday=3 August | 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 = UK Amateur Radio Bandplans Band Plans | work = | url = http://www.rsgb-spectrumforum.org.uk/Papers/Spectrum%20Forum%20Website%20Version%20(0606).htm | accessmonthday=3 August | accessyear = 2005

*cite web | title = Ham Radio QRP | work = | url = http://www.ac6v.com/qrp.htm#CALL | accessmonthday=3 August | accessyear = 2005

*cite web | title = IARU Region 1 Bandplan | work = | url = http://www.iaru.org/Chapter-5.1.pdf | accessmonthday=3 August | accessyear = 2005

*cite web | title = IARU Region 2 Bandplan | work = | url = http://www.iaru-regionii.org/Region_2_HF_Band_Plan.html | accessmonthday=3 August | accessyear = 2005

*cite web | title = IARU Region 3 Bandplan | work = | url = http://www.jarl.or.jp/iaru-r3/r3bandplan.doc | accessmonthday=3 August | accessyear = 2005