80-Meter-Band
As a 80 - meter band is defined as the frequency range of 3.5 MHz to 4.0 MHz. It is located in the shortwave spectrum. The name is derived from the approximate wavelength of this frequency range.
Propagation conditions
The propagation takes place mainly during the day over the bump ( range under 500 km); from dusk till dawn by the then existing space wave ( Range up to approx 4000 km ). Since the Maximum Usable Frequency ( MUF) rarely falls for this frequency range below 3.5 MHz, the propagation conditions are mainly during the day determined by the absorption of radio waves in the D- layer. Often, the same characteristics are as in the cutoff wavelength.
Antennas
Due to the wavelength of 80 m are half-wave dipoles in this frequency range, a length of 40 meters ( without taking into account the velocity factor ). They are called therefore often wrongly called " long wire antenna ", as often wires to the appropriate length between houses, masts or similar suitable stopping points are clamped. Correctly, a long wire antenna is more than a full wavelength long. There are also magnetic antennas, circular, square or rectangular (so-called magnetic loop - for example of a bicycle rim and copper tube) to be built. Such an antenna reaches several per mill efficiency in the 80 meter band. Disorders can be hidden by turning the antenna. However, the bandwidth of a few kilohertz is very low, so this type of antenna must be tuned at the tuning always ( remotely).
80 -meter amateur band
In amateur radio the 80 -meter amateur band mostly for local ( eg Germany -wide ) is used for radio radio contacts or connections with other radio amateurs on the same continent. This circumstance is due to the fact that the flat for a ( far conveniently ) radiation can only be achieved with installation heights above ground, which is not feasible for most radio amateurs (half wavelength, corresponding to 40 m). However, global connections are also quite at appropriate antennas possible.
The frequency ranges that can use the radio amateurs vary greatly. In some countries, complete 500 kHz are allocated to the amateur radio, in others only 300 kHz. And even this frequency range is often shared with other radio services.
Some countries deviate from these international assignments from (in MHz):
- Argentina from 3.500 to 3.750, from 3.790 to 3.800
- Australia from 3.500 to 3.700, from 3.766 to 3.800
- Canada from 3.500 to 4.000
- Japan from 3.500 to 3.575, from 3.747 to 3.805
- USA from 3.500 to 4.000
Band Plan
The band plan is as follows: