3 centimetres

This band is also known as the 10 GHz band. In the United States, it extends from 10.0 to 10.5 GHz.

Equipment

Commercially-manufactured gear for 10 GHz is nearly nonexistent. Amateur radio operators typically modify microwave gear intended for adjacent commercial bands. Because of a the small wavelength, extremely high gain antennas become practical. Typical 10 GHz antennas are dishes with gain of 30 to 40 dB, which means that very little power is required for high-quality voice communication.

Modulation

Although FM used to be widely used on this band, it has been largely supplanted by SSB.

Propagation

Although propagation on the band is largely line-of-sight, significant troposphere ducting does occur. Long-distance contacts have been made over hundreds of miles across Lake Superior.

Most 10 GHz QSOs are made through prearranged schedules, on nets, or during contests. Because of the high-gain antennas used, contacts are typically point-to-point, rather than initiated through calling CQ.