Narrow Band channels

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Narrow Band channels

Post by CPSK » Wed Feb 06, 2013 9:09 pm

As of Jan 1, 2013 the FCC requires all services (except pager) using VHF frequencies between 150 and 512Mhz be using narrow band modulation (12.5Khz vs 25Khz).
I have been using narrow band on my Yaesu/Vertex VX-150 radio for RR monitoring for about 6 mos now, since I realized that the volume level was too low when listening with wide band setting.
Now I am a bit confused as to why the AAR frequencies have to change for use with narrow band radios.
For example, AAR channel 58, 160.980Mhz becomes AAR channel 158 @ 160.9875Mhz in narrow band.
OK. Be it what it is. I suppose that the FCC requires the changes to allow more channels to fit into the same area of the spectrum.
But when I change my radio to 160.9875Mhz and narrow band, I hear nothing at all unless the signal is very strong, and then it is severely distorted.
I get the best reception when I leave the frequency alone (160.980Mhz) and set my radio on Narrow Band for the AAR channels.

In addition, I have found that I cannot enter all of the new AAR frequencies into my radio. For example, I can enter 160.9875Mhz, for AAR channel 158, but I cannot enter 160.6275Mhz for AAR channel 134. The radio jumps back to 160.6250Mhz.
I understand that this is a peculiarity of my radio, but I would be interested to know what experience everyone else is having with the switch to narrow band.
For now, it appears that at least for CSX in the New Jersey and New York area, the switch to narrow band has not changed the radio frequencies at all; just the bandwidth of the modulation from 25Khz to 12.5Khz.
That said, Amateur radio has been using a 5Khz bandwidth on two meters and 70cm for a very long time.


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Re: Narrow Band channels

Post by EMTRailfan » Thu Feb 07, 2013 10:55 am

Please read the wide to narrowband thread. Frequencies/spacing and narrowband/wideband are two different things.
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Re: Narrow Band channels

Post by CPSK » Thu Feb 07, 2013 4:20 pm


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