80 meter tape

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The 80 meter band is the frequency range from 3.5 MHz to 4.0  MHz . It is in the shortwave spectrum . The name is derived from the approximate wavelength of this frequency range.

Propagation conditions

During the day, it spreads mainly via the bump (range below 200 km); from dusk also through the then developing sky wave (range up to approx. 4,000 km). Since the Maximum Usable Frequency (MUF) for this frequency range rarely drops below 3.5 MHz, the propagation conditions are mainly determined by the absorption of the radio waves during the day in the D-layer . Often the same properties are present as with the limit wave . The International Telecommunication Union (ITU) provides range curves for the bump.

Antennas

Due to the wavelength of 80 m, half-wave dipoles in this frequency range have a length of 40 meters (without taking the shortening factor into account ). It is therefore often incorrectly referred to as a " long wire antenna ", as wires of the appropriate length are often stretched between houses, masts or similarly suitable holding points. Correctly, a long wire antenna is more than a whole wavelength long. There are also magnetic antennas that are circular, square or polygonal (so-called magnetic loops  - for example from a bicycle rim or copper tube). Such an antenna has an efficiency of a few per thousand in the 80 meter band. Interference can be suppressed by rotating the antenna. However, the bandwidth of a few kilohertz is very low, so this type of antenna must always be readjusted when searching for a station.

80 meter amateur band

In amateur radio, the 80-meter amateur band is mostly used for local (e.g. Germany-wide) radio contacts or for radio connections with other radio amateurs on the same continent. This fact is based on the fact that the (long-distance) flat radiation can only be achieved with installation heights above ground, which is not possible for most radio amateurs (half a wavelength, corresponds to 40 m). However, with the appropriate antennas, worldwide connections are definitely possible.

The frequency ranges that radio amateurs can use vary greatly. In some countries the entire 500 kHz is assigned to amateur radio, in others only 300 kHz. And even this frequency range is often shared with other radio services.

region Frequency range
IARU region 1 3.500 to 3.800 MHz
IARU region 2 3.500 to 3.850 MHz
IARU region 3 3.500 to 3.900 MHz

Some countries deviate from these international assignments (figures in MHz):

  • Argentina 3,500-3,750, 3,790-3,800
  • Australia 3,500-3,700, 3,766-3,800
  • Canada 3,500-4,000
  • Japan 3,500-3,575, 3,747-3,805
  • USA 3,500-4,000

Band plan

The band plan in IARU Region 1 is as follows:

Frequency range Bandwidth use
3.500-3.510 MHz 200 Hz CW, preferably intercontinental
3.510-3.560 MHz 200 Hz CW, preferred CW contest area , activity center 3555 kHz
3.560-3.570 MHz 200 Hz CW, low transmission power (up to 5 watts), contest-free area, activity center 3560 kHz
3.570-3.580 MHz 200 Hz Narrow band, digimode
3.580-3.590 MHz 500 Hz Narrow band, digimode
3.590-3.600 MHz 500 Hz Narrow band, digimode, automatic digital stations
3.600-3.620 MHz 2700 Hz all operating modes, digimode, automatic digital stations
3.620-3.650 MHz 2700 Hz all operating modes, preferably Contest SSB, activity center for digital voice transmission on 3630 kHz
3.650-3.700 MHz 2700 Hz all modes of operation, activity center for low-power radio ( QRP ) in SSB on 3690 kHz
3.700-3.775 MHz 2700 Hz All operating modes, preferably Contest SSB, activity center for image transmission on 3735 kHz, activity center for emergency radio on 3760 kHz
3.775-3.800 MHz 2700 Hz all modes of operation, preferably Contest SSB, primarily for intercontinental connections

literature

Web links

Individual evidence

  1. ↑ Ground wave propagation curves for frequencies between 10 kHz and 30 MHz ( English , PDF) International Telecommunication Union (ITU). Retrieved March 15, 2019.