Fall 2009 Issue
EmComm Gets Sky-High Boost
Amateur radio has an outstanding record of assisting with emergency communications. Emergency services recognize the hard work of hams around the world. We are sometimes the first and only link to the outside world until more help arrives. We provide additional communication links when the public safety channels clog with disaster traffic. We fill in the coverage holes that almost every communications system experiences.
One of the most common disaster communications interoperability problems arises when multiple agencies are required to respond to an incident. Each agency may utilize different radio frequencies, digital vs. analog modulation, and have limited ability to retune its equipment. At times, the geographic realities of the response environment impose additional constraints. Communication problems of this type are so common that the US Department of Homeland Security has established its Office for Interoperability and Compatibility to address the problem.1 Amateur radio operators have been able to fill in various interoperability problems with our frequencies and equipment.
Hams are well acquainted with radio coverage problems while providing emergency communications. The high-frequency bands suffer from hourly to daily propagation challenges. VHF and UHF simplex channels have limited geographic coverage. A repeater improves coverage while restricting all operations to its fixed channel pairs. Most of our current operating modes offer voice communications only. If data is transmitted it is supported at low rates such as 300, 1200, or 9600 baud.
Real world experience following disasters such as 9/11, Hurricane Katrina, and most recently with Hurricane Ike have shown that the first responders face damaged or destroyed communication infrastructure. Adding to the problem is that the remaining few wireless channels available become quickly clogged.
OK already! Enough discussion of the problems
we are all aware of! How about some solutions? A design under study at
AMSAT proposes flying an analog and digital 5- GHz uplink/3-GHz downlink
on a geostationary satellite carrying the AMSAT Eagle/Phase IV Advanced
Communication Payload (ACP). This could enable an amateur radio “Go Team”
to quickly provide unprecedented disaster communication support services
between stations within range of the satellite’s footprint. Stay tuned to
learn more about this satellite being designed. You will learn how it may
fit into the US Department of Homeland Security’s National Incident
Management System and its Incident Command methods of operating.
The AMSAT Eagle design team is proposing a communications payload that utilizes the amateur microwave allocations. With K3IO’s “strawman” design, the digital ACP channels would also be accompanied by some more conventional “bent pipe” linear transponder channels. Realizing that microwave Earth station design is beyond the scope of most hams, the Eagle team is considering options to make an ACP-capable Earth station within reach of most radio amateurs. The design work is still on-going, but it has been proposed that the Earth station may be distributed along the lines of the project kits offered by the Tucson Amateur Packet Radio group (TAPR). Radio-link budgets are being designed so the average Earth station could leverage the use of 0.9–1.0 meter (36–40 inch) diameter dishes and would appear similar to installations used for home satellite television.
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