The 15 metre amateur band covers 21.000 to 21.450 MHz. It’s one of the most interesting bands for DX communication. Situated between the 20 metre and 10 metre bands, it’s valuable for worldwide contacts during periods of good solar activity. The band has played an important part in amateur radio, especially during the great sunspot peak of the late 1950s and the solar peaks of later decades.
History of the 15 Metre Band
The band is relatively young compared with the older amateur allocations, such as 80, 40 and 20 metres. It was established internationally following the 1947 Atlantic City International Radio Conference, with amateur use beginning in the early 1950s. Before this, amateurs wishing to make long-distance contacts generally depended on the 20 metre and 10 metre bands.
Propagation
The outstanding feature of the 15 metre band is its ability to support very long-distance communication through the ionosphere. Unlike the lower-frequency amateur bands, 15 metres is dependent on solar activity. During the strong solar cycle of the late 1950s, the band became famous for remarkable worldwide communication using relatively modest transmitters and aerials.
British radio amateurs operating with valve transmitters and receivers regularly contacted stations in North America, Australia, New Zealand, Africa and Asia.
Radio signals transmitted on 21 MHz can be refracted by the ionosphere and returned towards Earth, allowing contacts over thousands of miles.
During periods of high sunspot activity:
- The band can open shortly after sunrise.
- European stations can communicate with Australia and the Far East.
- North American stations may be heard strongly during the afternoon.
- South America and Africa can provide excellent signals.
- Openings sometimes continue well into the evening.
During periods of low solar activity:
The band can remain closed for much of the day, especially during winter. Occasionally, only weak or short-duration openings occur. The 15 metre band is generally more reliable than 10 metres but less consistently open than 20 metres.