Narrowbanding

[fbaker]

Need clarification on this Narrowbanding in the VHF public service relm of 130-174 mhZ frequencies. I think I understand that all CURRENT frequencies move up, so to speak with an ADD factor of 7.5 thus creating two frequencies of the same number? I have not seen any changes on the frequency charts here like in the State mandated area. Thus, can I get a verify that let us say the old WIDEBAND frequency is - 155.280 the NEW narrowband will be - 155.355? If I am doing the math wrong would it be possible to show me the correct change? Thanks

 

[captclint]

Need clarification on this Narrowbanding in the VHF public service relm of 130-174 mhZ frequencies. Thus, can I get a verify that let us say the old WIDEBAND frequency is - 155.280 the NEW narrowband will be - 155.355? If I am doing the math wrong would it be possible to show me the correct change? Thanks

Welcome to RR. If you study the chart on this page: Narrowbanding - The RadioReference Wiki you should understand what has changed. Som in your example, the "new" frequency would be 155.2875. However, that does NOT mean that an agency must move to one of these new frequencies to be compliant with the Narrow band mandate. Many agencies have remained on their old frequencies while either making minor adjustments on their radios to take up less space, or they have purchased new equipment that is already compliant with Narrow banding if their radios were too old to make the adjustments.

 

[jim202]

There is no math involved. When a radio frequency is moved to narrow band operation, the audio deviation is reduced. In most cases, the old deviation was +- 5.0 KHz. Now the deviation is reduced to +- 2.5 KHz.

This then allows an additional radio channel to be dropped in between the old existing channels. However, there is a slight I gotcha there in the wood pile. You would not want a station operating on the splinter channel in the near operating range of an existing stations coverage area. The spatter from one or both the station would cause all sorts of complaints.

But this narrow banding does allow more users to be able to use the spectrum with sufficient distance between them. Thus allowing more stations to be licensed.

 

[Thunderknight]

Need clarification on this Narrowbanding in the VHF public service relm of 130-174 mhZ frequencies. I think I understand that all CURRENT frequencies move up, so to speak with an ADD factor of 7.5 thus creating two frequencies of the same number? I have not seen any changes on the frequency charts here like in the State mandated area. Thus, can I get a verify that let us say the old WIDEBAND frequency is - 155.280 the NEW narrowband will be - 155.355? If I am doing the math wrong would it be possible to show me the correct change? Thanks

No, a narrowbanded channel is the same frequency as the wideband channel. No frequency math needed.
That being said, narrowbanding did (in theory) create new channels in between, but nobody has to move there, and they would not be usable nearby with an existing licensed on the neighboring channel.

 

[fbaker]

Thank you gents for the information. That small conversion (if you will) table was what I was looking for. I had seen it somewhere in this site, just couldn't remember where. So the 'inbetween' channels are new but agencies will most likely stay with the 'old' frequency due to the FCC licensing regs., correct? That being said all that I have for programmed frequencies should work in my PRO-2096 for my area without any problems. I think that a lot of 'agencies' and their personnel don't quite understand this 'narrowbanding' as there are a lot of 'myths' being bantered about. Hope the 'techs' can get it straight to the end users without the 'I know about this" people giving out bad info. So, once again, thanks and I am now going to give my tech (wife) the scanner and have her go to town with data entry.