D-STAR - Criticisms

Criticisms

Proprietary codec

D-STAR uses a patented, closed-source proprietary voice codec (AMBE). Hams do not have access to the detailed specification of this codec or the rights to implement it on their own without buying a licensed product. Hams have a long tradition of building, improving upon and experimenting with their own radio designs. The modern digital age equivalent of this would be designing and/or implementing codecs in software. Critics say the proprietary nature of AMBE and its availability only in hardware form (as ICs) discourages innovation. Even critics praise the openness of the rest of the D-STAR standard which can be implemented freely. An open-source replacement for the AMBE codec would resolve this issue.

Bruce Perens, K6BP, amateur radio and open source advocate, evangelized the need for an open source codec for amateur radio. David Rowe, VK5DGR, has implemented an Alpha-test replacement codec under the LGPL and is continuing in its development.

Trademarked name

Despite many protestations from the Pro-D-STAR lobby that the standard was developed by the JARL, and D-STAR is not only an Icom system, the term 'D-STAR' is itself a registered trademark of Icom.

Usable range compared to FM

D-STAR has comparable usable range to FM but degrades differently. While the quality of FM progressively degrades the further a user moves away from the source, D-STAR maintains a constant voice quality up to a point, then essentially "falls off a cliff". This behavior is inherent in any digital data system, and demonstrates the threshold at which the signal is no longer correctable.

Emergency Communications Concerns

D-STAR's performance envelope relies heavily on internet connections. During widespread disasters that compromise commercial telecommunications infrastructure, D-STAR systems (and other modes that rely on the internet such as WinLink) may suffer outages or performance degradation that severely impacts operations. Without simulating such outages during drills, it is difficult to assess the impact or establish D-STAR service recovery procedures. As of the fall of 2011, there has been almost no discussion in the ham radio literature regarding actual drills where D-STAR systems were tested with failed or even intermittent telecommunications infrastructure. Comprehensive emergency communications plans used by ARES and other such organizations should address the possibility that such systems may not function as intended during major disasters.

Cost

D-STAR does add to the cost of a radio and is a barrier to the adoption of the technology. In 2006 the cost of a D-STAR radio was compared to that of a standard analog radio and the price difference was nearly double. This is due partly to the per-unit cost for the voice codec hardware and/or license, and partly to manufacturer research and development costs that need to be amortized. As is the case with any product, as more units are sold the R&D portion of the cost will decrease over time. The D-STAR capable radios also cost more than their equivalents from other brands, even before the D-STAR options boards are added (in the UK as of April 2011, Martin Lynch & Sons' website lists the Icom 2820 (without D-STAR) at £489, while the equivalent Yaesu, the FT8800, is listed at just £337).

Other available digital standards

Amateur radio operators have been using the more widely available Project 25 (P25) standard for some time and that digital mode offers features that are comparable to DSTAR. P25 was developed by the Association of Public-Safety Communications Officials-International for use by federal, state/province and local public safety agencies, and has been around since 1995. The P25 suite of standards is firmly established and has proven itself in multiple public service agencies. Equipment is available from multiple manufacturers rather than from just one with DSTAR. A drawback is that P25 is not manufactured for amateur use and commercial grade equipment must be used, and the cost of commercial radios that employ the P25 technology were even more expensive than that of off-the-shelf D-STAR radios. However, as of mid-2011, there is an ample supply of used P25 equipment at prices comparable to or less than that of new, mid-range ham gear. Motorola Astro Saber and Astro Spectra P25 transceivers can be found on eBay for $200 or less, well below the price of D-STAR equipment.

In addition, there are small pockets of amateurs in Europe experimenting with TETRA on the 70 cm band. However, the largest growth as of June 2011 was seen in Digital Mobile Radio and specifically Motorola's DMR product called MOTOTRBO. DMR is manufactured by nearly a half dozen manufacturers including Motorola. Since DMR is a worldwide standard, the radios from different manufacturers are interoperable on almost all features. DMR offers 2 digital voice channels from one repeater in 12.5 kHz channel bandwidth (also referred to as "6.25 equivalent").

Questionable legality

Many of D-STAR's opponents have argued that the proprietary codec constitutes a form of encryption, and encryption is prohibited by almost every country's amateur radio licence conditions. For the most part, regulators have ignored these claims, and allowed unbridled D-STAR use as with any other mode. However, the French regulators, in April 2010, have issued a statement that rules D-STAR illegal in France, due to the ability to create a connection to the internet with it, and because the codec used is proprietary. The French Amateur Radio society, DR@F - Digital Radioamateur France have an online petition against this ruling, calling for the government to allow the mode as to ban it would deny them 'fundamental rights'.