In the late 1990s, Tasmania was abuzz with the promise of a powerful new radio communications network, designed specifically to support the state’s essential services and utilities. The Enhanced Digital Access Communication System (EDACS) network was a ground breaking initiative built by the Tasmanian Hydro Electric Commission (HEC) in 1997. Its foundation in the 800 MHz band marked a significant step forward, aligning Tasmania with global trends toward smaller and more versatile radio units for professional and emergency use. It must be noted that this put Tasmania at odds with the rest of the country, who were building network in the 400MHz band, based on the APCO25 standard.
Origins and Early Days
The primary driver behind the creation of the EDACS network was the HEC, which managed the state’s electricity infrastructure and required a robust communication system to support its complex operations. The decision to go with the 800 MHz band was influenced by a global trend favoring this frequency, primarily because it allowed for smaller, more portable radio devices. In the EDACS network’s early years, the HEC and the broader government saw the potential to expand the system’s use to other organizations. Tasmania Police, intrigued by the system's capabilities, soon became the largest user of EDACS. The police presence helped anchor the network’s reach, and other organizations like Storaway and Spectrum Transport also signed on as early adopters.
However, the EDACS network wasn’t universally adopted. While Aurora and TasNetworks (formed after the HEC was split up) continued using EDACS, both Tasmania Fire Service and Ambulance Tasmania opted to expand their existing 70 MHz networks rather than switch to the new system. In time, the limited range of 800 MHz frequencies in Tasmania's unique terrain would lead to challenges.
Challenges of 800 MHz and Tasmania Police’s Aegis Experiment
One of the network’s most notable growing pains emerged from Tasmania’s rugged and remote landscapes. Although the 800 MHz band offered better urban coverage and compact equipment, it struggled in rural and forested areas. This limitation became particularly pronounced for Tasmania Police, who relied on the network extensively. In an effort to overcome these challenges and increase the security of their communications, Tasmania Police adopted the Aegis digital mode on EDACS, hoping the digital format would improve coverage, functionality and security. Unfortunately, the Aegis system experienced performance issues, prompting the police to revert to analogue talk groups by 2004.
Despite these setbacks, Tasmania Police continued with EDACS, gradually moving to ProVoice digital technology while maintaining a hybrid of analogue and digital modes. However, Tasmania Police’s reliance on the network led to an unexpected problem: overuse. The police’s extensive usage strained the network, leading to disputes and even legal action between the agency and the network operators. Ultimately, the Tasmanian government intervened, purchasing the EDACS network outright to secure its availability for emergency services and other state agencies.
System Evolution and the Transition to TASGRN (MK1)
The EDACS network saw widespread use throughout the 2000s and 2010s, with SES (State Emergency Service) joining in 2010 and remaining on the system until its closure in 2023. However, technological advancements and user demands outpaced EDACS over time. By the late 2010s, it was clear that the network required an upgrade, both for broader coverage and to meet the increasingly complex needs of emergency services.
In response, the state government initiated the Tasmania Government Radio Network (TASGRN) project, aiming to establish a more capable system across the 160 MHz and 420 MHz bands. This new network was designed with modern technology, expanded frequency bands, and better rural coverage to overcome EDACS’s limitations. TASGRN(MK2) became operational in late 2023, and agencies including Tasmania Police, Fire Service, Ambulance Tasmania, Aurora, TasNetworks, Parks and Wildlife, and Forestry Tasmania made the transition. The 70 MHz band, once bustling with activity, now lay virtually empty as services moved to the more advanced TASGRN.
Reflecting on EDACS’s Legacy
The EDACS network represented a cutting-edge solution when it launched, ahead of its time in many ways, especially in Tasmania’s context. Its initial goals were ambitious and largely fulfilled; it connected diverse users and facilitated critical communications for over two decades. For radio enthusiasts, it offered a unique challenge — decoding its structure, tracking talk groups, and mapping site locations became a rewarding hobby. While the limitations of the 800 MHz band ultimately led to its replacement, EDACS played a vital role in Tasmania’s history of emergency and utility communications, providing a foundation upon which today’s systems have been built.
As the TASGRN(MK2) network supports Tasmania into the future, the legacy of EDACS serves as a reminder of how far technology has come — and of the continual need to adapt to meet new challenges. EDACS may now be silent, but for those who remember its heyday, it remains a pioneering chapter in Tasmania’s communications story.
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