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received or where signal strength is marginal. To provide coverage in such areas, a distributed antenna
system (DAS) may be required. A DAS typically uses ported coaxial cabling to receive signals from an
exterior antenna and re-radiate this signal in areas where signal strength is deficient.
Project 25 (P25)
Project 25 (P25 or APCO-25) is a suite of standards for digital radio communications for use by Federal,
State/province and local public safety agencies in North America to enable them to communicate with other
agencies and mutual aid response teams in emergencies. In this regard, P25 fills the same role as the
European Terrestrial Trunked Radio (TETRA) protocol, although P25 is not interoperable with TETRA.
P25 addresses the need for common digital public safety radio communications standards for first-
responders and homeland security/emergency response professionals. The TIA’s TR-8 engineering
committee has published the P25 suite of standards as the TIA-102 series of documents, which now include
49 separate parts on Land Mobile Radio and TDMA implementations of the technology for public safety.
P25 standards are applicable to licensed LMR equipment and use voice-over-IP protocols to send data and
voice communications via LMR networks. Vulnerability to jamming remains an issue – because P25 radios
are designed to work in existing two-way radio frequency channels, they cannot use spread spectrum
modulation, which is inherently jam-resistant.
DHS Multiband Radios
The lack of interoperable public-safety radios has been a high-profile issue since the federal government
released the 9/11 Commission Report in 2004. The report said that in the aftermath of the terrorist attacks,
police departments struggled to coordinate their response plans because their radios weren’t compatible
with other departments’ communications systems. Local, state and federal agencies still use radios that
operate on different — and non-compatible — frequencies.
Traditional hand-held radios operate on only one frequency band, limiting first responders’ ability to
communicate across agencies and jurisdictions. In 2012, DHS addressed these long-standing challenges by
introducing a line of multiband radios (MBRs).
MBRs can operate on multiple, non-contiguous radio bands between 136 and 870 Megahertz (MHz). When
authorized, they can operate in the Department of Defense bands and two federal bands. The radios also
have GPS tracking devices and alkaline battery packs, which last more than 10 hours. Depending on how
they are deployed, the new MBR units have the potential to replace up to five conventional radios.
To encourage the adoption of MBR radios, DHS published an MBR procurement guide designed to assist
agencies in making informed procurement decisions by providing background information on operational
requirements for financial managers, a better understanding of the regulatory issues, and technical
capabilities of the MBR models and accessories available from the original manufacturers, as well as
secondary markets. The title of the guide is Defining Multiband Radio Requirements - A Procurement Guide
for Emergency Responders [Refer: Appendix A: References]
MBR radios will enable responders and high-level officials to communicate across agencies during an
emergency. While not replacing airport trunked radio systems, MBRs can provide links to off-airport
agencies that might not otherwise tie into trunked systems.
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