80 meters

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In telecommunications, 80 meters is a shortwave radio band used by amateur radio operators. The band spans frequencies from 3.5 to 4.0 MHz, at most, although only a small number of countries permit amateur radio activity on the whole 500 kHz.

Contents

1 Summary
2 Frequency allocation

2.1 United States bandplan

2.1.1 Key

3 Band plan

3.2 United States

4 See also
5 References

Summary

In amateur circles, 80 meters is most heavily used for relatively local or intra-continental communication, being the favoured home of nets from the same country or region and for long ragchews between relatively local amateurs. Many amateurs use low dipoles or loops on this band, which produce predominantly high-angle radiation, which is particularly useful for using Near Vertical Incidence Skywave and other relatively short distance propagation modes. During the daytime, a station in middle or high latitudes using 100W and a single element antenna would likely have a maximum communication range of 500–800 km, perhaps extending to 1500 km for a station using a kilowatt and antennas with some gain. These ranges are lower closer to the equator due to higher solar radiation which produces D-layer absorption.

As the maximum usable frequency for long distance communication seldom sinks below 3.5 MHz anywhere on the planet, the main propagation barrier to long distance communication is heavy D-layer absorption during the daytime, ensuring that DX paths must be largely, although not entirely, in darkness. In practice, the large physical size of antennas at this frequency – a quarter-wave vertical, for example, is over 20 metres high – and the difficulty of ensuring significant low angle radiation from antennas to maximise the distance of "hops" are more important constraining factors.

At higher latitudes, a noticeable skip zone sometimes appears on the band in during darkness hours in midwinter, which can be as much as 500km, rendering communication with some nearby stations impossible. This is not generally a problem at middle or equatorial latitudes, or for large parts of the year anywhere, but it does interfere with the heavy local wintertime traffic on the band in areas such as Northern Europe and Canada.

Frequency allocation

The International Telecommunications Union allocated the whole 500 kHz from 3.5 to 4 MHz to amateurs in the Americas, and 3.5 to 3.8 MHz to amateurs in other parts of the world. However, amateurs must share this useful piece of spectrum with other users, usually on a joint primary basis. As a result, authorities in many parts of the world can and have restricted amateur allocations.

Some allocations are as follows (in kHz):

Argentina 3.500–3.750, 3.790–3.800
Australia 3.500–3.700, 3.766–3.800
Canada 3.500–4.000
Europe (except Russia) 3.500–3.800
Japan 3.500–3.575, 3.747–3.805
New Zealand 3.500–3.900
Russia 3.500–3.650
United States 3.500–4.000

United States bandplan

US License Class	3.500 – 3.525	3.525 – 3.675	3.675 – 3.725	3.725 – 3.750	3.750 – 3.775	3.775 – 3.850	3.850 – 4.000
Novice / Technician Plus
General
Advanced
Extra

Key

	= CW, RTTY and data
	= CW, RTTY, data, MCW, test, phone and image
	= CW, phone and image
	= CW and SSB phone
	= CW, RTTY, data, phone and image
	= CW only

Band plan

United States

3.560	CW QRP calling frequency
3.579	CW QRP calling frequency (colorburst crystal frequency)
3.590	RTTY DX
3.580–3.620	RTTY
3.620–3.635	Packet
3.710	CW QRP calling frequency (Novice)
3.790–3.800	DX window
3.845	SSTV
3.885	AM calling frequency
3.985	SSB QRP calling frequency

References

Medium (MF) and High frequency (HF) Amateur radio bands for ITU Region 2
MF HF

160 m 80 m 60 m 40 m 30 m 20 m 17 m 15 m 12 m 10 m
1.8 MHz 3.5 MHz 5 MHz 7 MHz 10.1 MHz 14 MHz 18.068 MHz 21 MHz 24.89 MHz 28 MHz
2 MHz 4 MHz region 7.3 MHz 10.15 MHz 14.35 MHz 18.168 MHz 21.45 MHz 24.99 MHz 29.7 MHz

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Medium (MF) and High frequency (HF) Amateur radio bands for ITU Region 2
MF	HF

160 m	80 m	60 m	40 m	30 m	20 m	17 m	15 m	12 m	10 m
1.8 MHz	3.5 MHz	5 MHz	7 MHz	10.1 MHz	14 MHz	18.068 MHz	21 MHz	24.89 MHz	28 MHz
2 MHz	4 MHz	region	7.3 MHz	10.15 MHz	14.35 MHz	18.168 MHz	21.45 MHz	24.99 MHz	29.7 MHz