NPSTC’s Home Page features a digital clock counting down the days, hours, minutes, and seconds until mandatory narrowbanding begins. In 3 short years, all radio systems operating at frequencies below 512 MHz will be required to narrowband, i.e. begin operating in 12.5 kHz channel bandwidths instead of the current 25 kHz channel bandwidths in use today or meet the efficiency standard of two talk paths in 25 kHz. The Federal Communications Commission (FCC) has mandated that narrowbanding be complete by January 1, 2013. What does this mean to you? It means that many existing systems operating in these bands will need to be modified or replaced.
But, the clock may be ticking even more quickly than you think. By January 1, 2011- a little over a year away- the FCC will no longer accept new or modified applications that exceed the narrowbanding guidelines, which means that a modification to expand the interference contour of an existing station will not be accepted. It means that the manufacture or importation of equipment will be limited to 12.5 kHz technology. So if an agency's 25 kHz bandwidth-only equipment is damaged or lost, replacement equipment may not be readily available after January 1, 2011. Another thing to consider is the fact that it is not unusual for public safety agencies to expand or change the geographic areas for which they are responsible, but these changes would not be permitted by 2011 for systems that operate exclusively at 25 kHz, unless they meet the efficiency standard, e.g. utilize two or four slot TDMA.
And wait, there's more. Although a deadline for the second phase of narrowbanding, conversion to 6.25 kHz channel efficiency, has not been specified by the FCC for VHF/UHF licenses, a deadline has been established which requires 700 MHz channels to operate at 6.25 kHz efficiency by January 1, 2017.
For more go to -
Narrowbanding Tech Brief
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