Narrow Band Radio Systems

[fireresq243]

The county I live in is looking into getting a narrow band radio system. I have never heard of them before and I wasjust wondering what they were. Are they 800mhtz. Could someone let me know. Thanks

[GregH]

As I understand it, older radios worked with frequencies spaced 25 kHz apart to prevent interference between frequencies. With the number of new frequencies being requested, new equipment has to be narrow band equipment, which uses a smaller (narrower) bandwidth so that frequencies can be spaced 12.5 kHz apart, which essentially doubles the number of frequencies available for use.

[fireresq243]

Thanks. That helps me out a lot

[NorthSTAR]

Also, because the channels are now only 12.5khz apart- the voice path is reduced to 2.5khz from 5khz. The means that audio compression and expansion hardware is required to make your voice sound nornal. Most public safety radios have this capability today, but ones made before 2000 likely do not.

Almost everything you need to know about narrowband operation can be found at this link: http://www.apcointl.org/frequency/documents/NarrowbandOrder.html

[fireresq243]

Sorry I haven't replied for a while. Thanks for the info it was real helpful