2.2 kilometer tape

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The 2.2 kilometer band is the frequency range from 135.7 kHz to 137.8  kHz . It is in the long wave spectrum . The name is derived from the wavelength of this frequency range.

2.2 kilometer amateur band

The 2.2-kilometer band is the only long-wave band in amateur radio and thus the lowest band assigned to amateur radio. Radio amateurs do broadcasts on lower frequencies (vA VLF on 8270 Hz, "Dreamers Band"), but without official frequency allocation.

Band plan

The amateur radio - band plan is as follows:

Frequency range Max. Bandwidth use
135.7-136.0 kHz 200 Hz CW, station tests, QRSS
136.0-137.4 kHz 200 Hz CW
137.4-137.6 kHz 200 Hz Digimode, no CW
137.6-137.8 kHz 200 Hz CW, activity center QRSS 137.7 kHz

Devices and antennas

Due to the long wavelength, transmission activity on the 2.2 kilometer band is demanding and can only be carried out successfully by relatively few radio amateurs on a regular basis.

Accordingly, commercially available devices are generally not designed for transmission on these frequencies. With a few exceptions, practically only do-it-yourself devices are used.

One of the greatest challenges in broadcasting is setting up a transmitting antenna. Usually, vertical antennas fed to ground are used, such as the T antenna or an inverted L antenna. The efficiency of a 2.2 km transmitting antenna that can be achieved by radio amateurs with reasonable effort is usually less than 1%. The losses mainly occur in the soil.

In most countries, the maximum permissible radiated power is 1 W EIRP. This may sound like little at first, but due to the efficiency it can only be achieved with considerable effort.

Wave propagation

In the 2.2 kilometer band, with 1 W of radiation power, radio connections are possible day and night over several hundred to thousands of kilometers. The daily damping is, however, significantly increased. During the day, the wave front is reflected on the underside of the ionospheric D-layer. Due to the low electron density in the D-layer, this is only possible on long-wave and longer wavelengths; The layer has an absorbent effect on medium and short waves. After sunset the D-layer dissolves very quickly, the long wave is then reflected or scattered much more efficiently at the E-layer.

Industrial engineering

Voice connections are not permitted due to the limited bandwidth available (see band plan). Beacon modes are widely used. These are not used to exchange information, but to determine the wave propagation conditions and antenna comparisons. These are currently (January 2020) WSPR ( FSK ) and Opera32 ( OOK ). JT9 ( FSK ) and CW (Morse Code) are mainly used for communication between amateur radio stations . The latter both with the Morse code key and with machine-generated Morse code, which is stretched over time to improve the signal-to-noise ratio (QRSS).

Web links

Individual evidence

  1. ↑ ON7YD, long wave, 136 kHz, antennas. Retrieved October 6, 2019 .