AM expanded band

The extended mediumwave broadcast band, commonly known as the AM expanded band, refers to the broadcast station frequency assignments immediately above the earlier upper limits of 1600 kHz in International Telecommunication Union (ITU) Region 2 (the Americas), and 1602 kHz in ITU Regions 1 (Europe, northern Asia, and Africa) and 3 (southern Asia and Oceania).

In Region 2, this consists of 10 additional frequencies, spaced 10 kHz apart, and running from 1610 kHz to 1700 kHz. In Regions 1 and 3, where frequency assignments are spaced 9 kHz apart, the result is 11 additional frequencies, from 1611 kHz to 1701 kHz.

The extended band is not officially allocated in Europe, and the trend of national broadcasters in the region has been to reduce the number of their AM band stations in favor of FM and digital transmissions. However, new Low-Power AM (LPAM) stations have recently come on the air from countries like Finland, Sweden, Norway, Denmark, the Netherlands, and Italy. These frequencies are also used by a number of "hobby" pirate radio stations, particularly in the Netherlands, Greece, and Serbia. Vatican Radio for many years transmitted on 1611 kHz, before ceasing broadcasts on this frequency in 2012. Since 2014, a licensed Norwegian project has been broadcasting both Radio Northern Star and The Sea on 1611 kHz.

In 1979, a World Administrative Radio Conference (WARC-79) adopted "Radio Regulation No. 480", which stated that "In Region 2, the use of the band 1605-1705 kHz by stations of the broadcasting service shall be subject to a plan to be established by a regional administrative radio conference..." As a consequence, on June 8, 1988, an ITU-sponsored conference held at Rio de Janeiro, Brazil, adopted provisions, effective July 1, 1990, to extend the upper end of the Region 2 AM broadcast band, by adding 10 frequencies which spanned from 1610 kHz to 1700 kHz. The agreement provided for a standard transmitter power of 1 kilowatt, which could be increased to 10 kilowatts in cases where it did not result in undue interference.

Even before the formal adoption of the expansion, a 50,000-watt religious station located on the island of Anguilla, British West Indies, was broadcasting on 1610 kHz as "The Caribbean Beacon". This station dated to the early 1980s, and is no longer on the air.

In Argentina, the expanded band assignments are primarily in the region surrounding the nation's capital, Buenos Aires.

Canada has made an informal agreement with the United States to allow Canadian stations operating on 1610, 1630, 1650, 1670, and 1690 kHz to be located closer to their common border than would normally be allowed, in exchange for allowing the U.S. the same privilege on the other frequencies. Therefore, all of its limited number of expanded band stations currently operate on these frequencies.

There have only been a few expanded band stations established in Cuba. The most commonly used frequency is 1620 kHz, where multiple stations simulcast Radio Rebelde network programming.