AM expanded band
The band became officially available around 1993—only in ITU region 2 (North and South America). It is popular with microbroadcasters for having slightly better propagation characteristics than the standard AM band.
Though supported on most (but not all) modern AM radio receivers sold in the Americas, this band is usually unavailable to older radio receivers except for those with substantial overcoverage. 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.
In the United States of America, the FCC granted "stereo preferences" to commercial broadcasters intending to use AM stereos when issuing licenses for the bandcitation needed. 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.original research?
Expanded band stations generallyvague 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 mayvague be 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.citation needed).
Because 1610 kHz (the top or right-most channel on analog radios) had previously been reserved for Travelers' Information Stations (TIS) as 530 kHz—the bottom or left-most channel still is. Some TIS stations were displaced for new expanded-band stationscitation needed. There are no AM stations in the United States licensed to 1610 kHz 1
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. This results due to the fact that aeronautical radionavigation may use 1708 kHz,.2
However, they have restrictions not placed on licences for the standard mediumwave band: e.g. 5 kHz bandwidths and type H3E emissions, as used by CHU in Canada on shortwave, without reducing sound quality.
- 47 CFR §90.103
- FCC document on AM expanded band
- A proposal to use the expanded MW band for international broadcasting in Australia and NZ