Background - The future of two way radio is digital.

As of 2007, TV broadcasters in the other areas of spectrum are required to be full digital and shut down their analog transmitters in Feb. 2009.  The only spectrum broadcasters are required to vacate are channels 64 thru 69 that will become the new "700 MHZ band" that is being auctioned off by the FCC.  The vacated areas of this spectrum will be utilized for: Public Wireless deployment (Cellular/PCS); A wide-band private data network that will be shared between public safety and paying customers; and new spectrum for public safety that will butt right up to the re-located NPSPAC National Public Safety Planning Advisory Committee band being moved to 806-809/851-853 by Sprint/NEXTEL.  All non-public safety stations to operate on channels with a bandwidth of 12.5 kHz or less beginning January 13, 2013. Until 2013 (maybe), public safety users may continue to use 25-16 (wide band) kHz equipment. Phase 2, which becomes mandatory (maybe) in 2018 would require radios capable of operating at 6.25 kHz. (Digital Non-analog FM). The future of two way radio is digital, and we must also advance in this direction. The digital premise is that it generally allows more use in a more efficient/flexible use of band space.

A process of "refarming" the informal name of a notice and comment rule-making proceeding (PR Docket No. 92-235) opened in 1992 to develop an overall strategy for using the spectrum in the private land mobile radio (PLMR) allocations more efficiently to meet future communications requirements.  The FCC created mandates for the two-way radio equipment manufacturers. In 1997, all new two-way radio models had to be capable of operation on the "new 12.5 kHz narrowband" channels. This is often called "dual-mode" equipment since the radio can accommodate both narrow- and wide-band channels. The idea was to begin to move gently toward narrowband channel operation over time. At that time, the FCC did not create any mandates to remove older wideband radio units from service or require you to use a new narrowband channel.

The Part 90 LMR narrowbanding mandate was released 12-23-2004 by the FCC for all Part 90 business, educational, industrial, public safety, and local and state government two way radio system licensees currently operating legacy "wideband" (25 KHz) voice or data/SCADA radio systems in the 150-174 MHz (VHF) and 421-512 MHz (UHF) bands.  The executive summary of the FCC order establishes January 1, 2013 deadline for migration to 12.5 KHz technology.

Hams benefit because a lot of used equipment  will start showing up. Oddly enough while  most ham repeater coordination bodies, coordinate / assume traditional 16 kHz wide-fm bandwidth, D-Star boasts it's spectrum efficiency with a 6kHz bandwidth for ham radio.


While that is nice, it's not necessary at all.   Hams are not bound by these narrowband rules, refarming nor will there ever likely even ever be a rebanding.  We have oodles of spectrum available to us, most of it un-used.


What is actually disappointing about D-Star is that  it's only a 4800 baud total data stream equivalent signal.  2400 bps is reserved for actual digital voice, 1200 bps is reserved for FEC (forward error correction)  on the digital voice.  (This is for callsign and short message data.)  1200 baud is reserved for serial data low speed digital data .  (This is for APRS, and text messages/text query's.)  The sad part is 1200 baud data is what we were doing in the 1980's. 


So if 4800 baud can fit into a 6kHz bandwidth, we could have had a 12800 (12.8k) baud total data stream equivalent signal fit into our existing 16 kHz bandwidth plans.  This could have left us with 9.2k left for data.  Or at the very least more could have been given for the digital voice codec, so that we could use other license free-codecs that sound more natural.

Toward Software Defined Radios and Digital Voice

Obviously you gravitate towards things.  You don't just expect to, like a light switch, convert everyone to purely digital radio.  

It would be logical at this day in age if you're planning on upgrading a repeater system to ensure that it can repeat analog and some form of digital.   P-25 systems and Motorobo systems can do just this.  Just as if you are considering a new HT or mobile to purchase something that is digital capable like the IC-91AD or the alike.

Technology is ever changing, which makes standards hard to set.  This is why open standards are so very important.  It expedites production and advancements , as you are effectively working together or sharing information.  Be wary of  any thing proprietary, as this impedes technology and is terribly unhealthy for the hobby.  

Protocols and standards need to be dynamic as possible to avoid equipment obsolesce.  This is where the software defined radio (SDR) concept is key.  However once again between here and there, manufactures should highly consider flash/field upgradeable firmware.

Just about everything has this, from phones to PDA's to routers.  An upgrade can fix a bug or give you added functionality.  The most classic example I can think of is the Linksys WRT-54G.  They grasped the open source concept and made a product that so many people have written after-market firmware for that has unlocked a wealth of added functionality.

Why don't we have more of this?  We are hobbyist and tinkerers that are supposed to be advancing the radio art.    Societies electronics evolvement has made traditional homebrewing difficult. Components are smaller and harder to work with, things are designed more throw away. However homebrewing should and will continue. It will evolve to a more modular and software level than component level.  As things progress increasingly more digital, the emphasis need to be on firmware upgradeable, open source, and user end flexibility. 

Yeasu and others seem to rush radios to the stores probably to beat the competitors, but they often suffer some firmware bugs.    The only way to have these resolved is to send the radio in.  Unless others follow in the footsteps like Kenwood apparently did.  

In summary an emphasis should be on dynamic protocols, and products that provide a capability bridge as well as upgradeable platforms.  Products that lack in these key areas are potential road blocks to the future.  I'm certainly not buying expensive radios every year, so a little foresight is all we need.

Having systems that are open to 3rd party developers (think: the best-selling router of all - the classic WRT54G), have an active developer and user community, and use open protocols have the best chance of succeeding. Hams like to tinker and also to have someone else to talk to when they need to test their tinkering.

Be wary of any product that isn't built with dynamic architecture.   Built-in obsolescence or proprietary features are excuses to force acquisition of new products.