The Texas VHF-FM Society - Narrow Band Information
Update 10/17/2011 - The Society is currently working to establish a new "narrow band" segment or sub-band on 2 meters in the 145 MHz range. "Narrow band" does not mean just digital format but includes lower deviation analog as well. When completed this should create 4 new repeater pairs in the 145 MHz "narrow band" sub-band.
Looking back over the last 50 years or so, technology has changed quite a bit.
In the 1960's Frequency Modulation was a relatively new technology to the Amateur bands. At the time, 30 KHz deviation was the norm.
As technology advanced, it was possible to use progressively narrower deviation which allowed more systems to be accommodated in the same spectrum.
Eventually we moved to 15 KHZ and then to 5 KHz. We now find ourselves on the very same threshold again.
All of the commercial and most of the Amateur equipment manufactured in the last few years includes capability for both 5 and 2.5 KHz deviation.
In a short time, the FCC will deny type acceptance for any new commercial equipment capable of operating in any mode wider than 2.5 KHz below 512 MHz.
We can see the handwriting on the wall. It is time to start preparing for the future.
In certain areas of the state, North Texas most notably, we have waiting lists for repeater pairs.
Although there are coordinated pairs out there that are not being used, recovering only those unused pairs will still not provide relief for everyone waiting.
The Society needs to explore new ways to accommodate more systems and users in the spectrum we have been allotted. One of the options is moving to 2.5 KHz narrow band technology. Some systems are already being operated using narrow band analog and digital technology.
In order to accommodate these systems, the Society needs to look at refarming parts of the bands for this purpose.
In North Texas, the lower portion of the 145 MHz repeater sub band is one of the most attractive portions for establishing a narrow band segment. Here is a look at the current 20 KHz configuration:
145.110
145.130
145.150
145.170
145.190
145.210
145.230
7 pairs
We propose that the band be refarmed for 12.5 KHz separation. The new configuration would be as follows:
145.1125
145.1250
145.1375
145.1500
145.1625
145.1750
145.1875
145.2000
145.2125
145.2250
145.2375
11-pairs
Once the band was reconfigured by migrations and frequency swaps, the first thing to do would be to offer those on the current waiting list a chance to take one of the new pairs with the stipulation that they must construct a narrow band analog or digital system.
They could also opt to remain on the list awaiting a regular 5 KHz pair. Once every person on the list had been offered such an option, if there were any pairs remaining, these pairs would be offered to the operators of any narrow band system currently operating on a conventional wide pair in order to migrate them into a part of the band where the benefit of their greater spectral efficiency could be realized.
