12.5 kHz versus 25 kHz Bandwidth

There are two possible bandwidths that can be set in the 450 MHz RTK radio:

25 kHz	Wideband
12.5 kHz	Narrowband

The 25 kHz bandwidth delivers twice the baud rate of the 12.5 kHz. Wide bands have more data capacity and faster message transmission than narrow bands. In the RTK system, this results in a more robust data link. However, the disadvantage to using a larger bandwidth is that fewer licensed frequencies are available to applicants. To more efficiently use the available frequencies, some spectrum authorities are transitioning from older wideband licensing plans to narrowband licensing plans.

For example, in the United States the FCC has established January 1, 2013 as the deadline for migration to 12.5 kHz technology. Applications for wideband operations (25 kHz channels) will be accepted until January 1, 2011. All existing Part 90 radio systems operating on frequencies between 150-512 MHz have eight years to convert those systems either to 12.5 kHz bandwidth or to a technology that provides one voice path per 12.5 kHz of bandwidth or provides a data rate of 4800 bps per 6.25 kHz.