In Brazil, the frequency 87.9 FM is reserved for
community radio stations. These stations have power limited to up to 25 watts and coverage limited to a radius of up to 1 km.[1]
In 1945, the standard FM broadcasting band was assigned to channels that started at 88.1 MHz.[6][7] 87.9 MHz was added in 1978, as part of a project to improve use of the non-commercial channels of 88.1 to 91.9 MHz. 87.9 MHz was designated as a potential assignment for existing 10-watt "Class D" stations which were unable increase their power to at least 100 watts, and also could not be moved to the adjoining commercial channels of 92.1 to 107.9 MHz.[8] Because 87.9 is also part of TV Channel 6 in the United States, its use by radio is restricted to low-power stations meeting certain strict criteria, licensed for operation on FM Channel 200.
There are no radio stations on 87.9 MHz in the United States after the license of
KSFH was deleted in December 2021, however there is one translator licensed to the frequency. The station is K200AA in Sun Valley, Nevada, a translator of
CSN International. The translator was given a special grant by the FCC to move to 87.9 MHz from 88.1 MHz to protect
KYSA in Sparks, Nevada, which is on 88.3 MHz.
2 Shortwave uses a combination of
AM,
VSB,
USB and
LSB, with some
NBFM and
CW/
morse code (in the case of
time signal stations) as well as numerous frequencies, depending on the time of day/night, season, and solar activity level. A reasonably full list from 16 kHz to 27MHz can be found at
[1]
3 Regions 1 and 3 also use Region 2's frequencies as well, with 50 to 100 kHz spacing.