[1][2] They were named after the World Administrative Radio Conference, which in 1979 created a worldwide allocation of these bands for amateur use.
This agreement has been codified in official recommendations, such as the IARU Region 1 HF Manager's Handbook, which states: "Contest activity shall not take place on the 5, 10, 18, and 24 MHz bands.
"[3] Non-contesting radio amateurs are recommended to use the contest-free HF bands (30, 17, and 12m) during the largest international contests.
[10] The band segment 10.12 to 10.14 may only be used for SSB transmissions in the area of Africa south of the equator during local daylight hours.
[11][12] Australia (VK, region 3) has a unique set of privileges on 30 meters which allows voice operation on a section of the band for advanced license holders.
These are WIA [13] recommendations only as ACMA does not restrict Australian amateurs' modes within HF allocations beyond requiring less than 8 kHz occupied bandwidth per channel below 28 MHz.