3 centimeter tape

Californian radio amateur with microwave equipment for 10 GHz

The 3-centimeter band is an amateur radio band in the frequency range from 10,000 GHz to 10,500  GHz . It is in the microwave spectrum . The name is derived from the wavelength of this frequency range.

Propagation conditions

The propagation conditions in this band are even more similar to those of light than in less high-frequency bands. With an unobstructed view of the horizon, tropospheric weather conditions result in interesting propagation paths. Radio amateurs take advantage of these weather conditions with highly bundled directional antennas ( with parabolic mirrors ).

One way of propagation is rain scatter connections, in which the antenna is directed into a rain cloud or thundercloud. The raindrops reflect the radio waves in forward scatter, back scatter or side scatter, i.e. further forward, backward or to the side. As a result, several hundred kilometers of transmission path can be overcome with relatively little effort.

Regenscatter can be operated in the summer months from the end of April to October as long as the rain or storm clouds are not frozen. Ice crystals and snow reflect the 3 cm waves very poorly or not at all.

Another way of propagation in special weather conditions is inversion weather, as on the lower VHF bands . In large high-pressure areas, there are warm layers of air with a sharp boundary on top of cold air layers. The weather is very calm. The radio waves glide along this boundary between the two layers of air and several hundred to over a thousand kilometers can be stably bridged through the high pressure area.

First connection and range record

The first two-way amateur radio link in the 3 cm band was established in 1946 by American radio amateurs . The current range record for terrestrial connections was achieved in January 2015 by two Australian amateur radio stations and is 2,732 km. On September 9, 2017, a new range record was achieved in this band for earth-moon-earth connections. An Australian amateur radio station came into contact with a US amateur radio station in Delaware 18,949 km away . The digital operating mode QRA64D by Joe Taylor was used .

Band plan

The amateur radio band plan is as follows:

Frequency range	use
10,000-10,150 GHz	digital communication
10.150-10.250 GHz	all operating modes
10.250-10.350 GHz	digital communication
10.350-10.368 GHz	all operating modes
10.368-10.370 GHz	Narrow band, activity center 10,368,200 MHz
10.370-10.450 GHz	all operating modes
10.450-10.500 GHz	Amateur radio satellites

Web links

• Frequency usage plan according to § 54 TKG of the Federal Network Agency

Individual evidence

1. ^ First activity on 10,000 and 21,000 Mc. In: QST , July 1946, p. 140.
2. ↑ New world record claimed on 10 GHz.
3. ↑ New 10 GHz Earth-Moon-Earth world record set.