What exactly is narrowband?

Current wideband channels are 25 kHz wide and are spaced 15 kHz apart. The FCC is requiring both the bandwidth and the spacing be cut in half resulting in 12.5 kHz channels spaced at 7.5 kHz.

Why is narrowbanding required?

It is an FCC mandated rule that is intended to increase the number of usable voice channels. In practice, however, it appears that the narrowband emissions of two channels, 7.5 kHz apart, may overlap and cause worse interference than existed at wideband with 15 kHz separation. This is partly why the railroads have decided to avoid the use of 7.5 kHz separation or use of the interstitial channels for narrowband.

If my current channel takes up the space of two narrowband channels, will I get two narrowband channels for my one wideband channel?

No, the new channels will be treated as new channels and will have to be applied for and coordinated as any other channel.

Will I get to keep the same channels I have?

Yes, for now. The AAR and the member railroads are working on a plan for re-allocating channels to reduce interference and to increase the total number of usable channels in congested areas.

Will I lose range when I switch to narrowband?

Initial tests have shown very little, if any, change in range.

When are the mandate timelines?

July 1, 2010 is the date the railroads have voluntarily decided as the date when all locomotives will be narrowband capable. That will give them six months to catch any locomotives they may have missed.
January 1, 2011 is the date that wideband applications or modifications will no longer be accepted. All new applications or modifications must be for narrowband or very narrowband.
January 1, 2013 is the date when wideband operation will no longer be permitted.

What happens if I don’t migrate?

The FCC has said that as of January 1, 2013, it will cancel all licenses that do not have narrowband or very narrowband emissions on the license.

It is important that you coordinate your migration to narrowband with the other railroads you talk to.

Can I keep my current radios?

If your radios are capable of narrowband analog operation, there is no need to replace them to meet the 2013 narrowband deadline. However, in order to distinguish between wideband and narrowband on the same frequency, the railroads have decided to add a leading zero to the narrowband channel number. Thus, channel 52 is wideband and 052 is narrowband on the same frequency. If your radios cannot display leading zeros, you may want to replace them anyway.

It appears that in narrowband mode, most radios are compatible. However, the FCC has stated that narrowband is just an intermediate step to very narrowband but has not set a date yet when that will be required. The AAR recommends that all new radios purchased be very narrowband (NXDN) compatible.

What is very narrowband?

Very narrowband is the requirement to transmit one voice channel per 6.25 kHz of spectrum. Because all very narrowband radios are digital, it is also defined as 4800 bps of data per 6.25 kHz channel width. There are several technologies available that accomplish this goal, but the railroads have selected NXDN technology primarily because there are multiple vendors supporting it.

With the FCC saying narrowband is just an intermediate step to very narrowband, will I have to switch to very narrowband in a few more years?

The FCC generally gives about 10 years notice before requiring a new technology, but it is better to purchase very narrowband radios as old radios are replaced than to have to replace all the radios at one time. In addition, migrating to very narrowband sooner will make more channels available.

How much does it cost?

The AAR Frequency Coordination office will add narrowband and/or very narrowband emissions to all frequencies on the license for $85. If other information on the license must also be updated, the fee will be $135. The FCC charges $60 for a modification. The FCC is also allowing licensees to change a wideband emission to narrowband for the modification charge of $60 without going through a coordinator as long as no other technical changes are requested or required. A change from wideband to narrowband will require operation on narrowband.