AM expanded band

The extended mediumwave broadcast band, commonly known as the [AM] expanded band, is a broadcast frequency allocation. It moves the upper limit of the AM bandplan from 1610 to 1700 kHz.

History

The band became officially available around 1993—only in ITU region 2 (North and South America). It is popular with micro-broadcasting for having less interference due to less signals than the standard/legacy AM band.

Though supported on most modern AM radio receivers sold in the Americas, this band is usually unavailable to older receivers except for those with substantial extended coverage. On such radios, the 1600-1700 segment was labeled "Police", since it was the original 'police radio' band. In the U.S., coverage on newer radios is mandated by the Federal Communications Commission (FCC), invoking the All-Channel Receiver Act.

Regional use

Americas

In the United States of America, the Federal Communications Commission voted to support an expanded band on April 12, 1990.^[1] The FCC granted "stereo preferences" to commercial broadcasters intending to use AM stereo when issuing licenses for the band. However, such stations have never been required to broadcast in stereo. With the evolution of the AM band becoming more talk radio than music, it is unlikely that the FCC would take any action against an extended-band station only broadcasting in monophonic sound.

The standard for FCC licensed Expanded band stations has been broadcast omnidirectionally with ten kilowatts of power in the daytime and one kilowatt at night—except for stations that use antennas with higher than normal efficiency or those multiplexed with an existing station on a different frequency. In those cases, they are by FCC Part 73 rules only authorized to less than one kilowatt at night; generally limiting such stations to 281 millivolts per meter per kilowatt at one kilometer, the minimum efficiency for a Class B station under FCC Part 73 rules. One station, 1700 license to Brownsville, TX, operates at 12% less than the standard (8.8KW Day and 880 watts at night) due to treaty with Mexico.

Because 1610 kHz (the top or right-most channel on analog radios) had previously been used for Travelers' Information Stations (TIS) as 530 kHz — the bottom or left-most channel — still is (though 530 is NOT a FCC US AM Broadcast channel, some TIS stations were displaced for new expanded-band stations . There are no AM stations in the United States licensed to 1610 kHz ^[2]

While 1710 kHz appears on many radios, it is unused even by TIS stations, except for a group (WQFG689) licensed with a waiver to the County of Hudson in New Jersey. This is due to the fact that TIS stations are authorized under Part 90 of the FCC rules which deal with all two way radio [except marine (Part 80) and ham/amateur radio (Part 97)] and not Part 73 or 74 which are the broadcast rules.

Greater Europe

Although the extended band is not officially allocated in Europe, it is used by Vatican Radio and a number of "hobby" pirate radio stations, particularly in the Netherlands, Greece, and Serbia.

Australasia

In Australia, many commercial radio broadcast licences have been authorised for the extended band.

The vast majority of licences have never been used. Due to a number of factors, few Australian stations in this band have many listeners.

The Philippines

In the Philippines, the first AM expanded band radio station in low power format broadcasting in Marikina City is DZBF DEL Radio - Radyo Marikina 1674 kHz started in July 25, 1996.

References

External links

• FCC document on AM expanded band
• A proposal to use the expanded MW band for international broadcasting in Australia and NZ