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WHAT IS P25 Phase 2?
AURORA'S NEW RADIO SYSTEM

The Federal Communications Commission now requires all commercial and public safety radio systems to use Narrowband modulation  as of January 1, 2013!
 
This means that most radio systems between 150 MHz and 470 MHz, which were permitted to modulate their signals up to 25 Kilohertz (kHz) wide are required to reduce their modulation to 12.5 kHz. This will permit twice as many signals in the same amount of frequency space.
 
For you as a listener, it means you should change the modulation mode in your scanner programming to NFM (Narrow Frequency Modulation) on any channel which has narrowbanded. If you do not make that change, or your radio does not have that mode, the audio of the signal you are receiving may sound 'weak', as if the user is not speaking loudly enough, and you will need to turn up the volume to hear that system well. If you do not make this change, you will not 'lose' that system, you just won't hear it quite as clearly. When a transmitter is narrowbanded, the range will be reduced by approximately 3dB; approximately 50%.  Many systems have already switched to narrowband, and you may not even be aware of it.  When they were first authorized, 700 MHz and 800 MHz systems were set up as narrowband, so they will not change.  This requirement does not apply to amateur radio transmissions, which will remain full-width FM for now, although they can use narrowband (NBFM) if they wish.