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close this bookEmergency Information Management and Telecommunications - 1st Edition (Department of Humanitarian Affairs/United Nations Disaster Relief Office - Disaster Management Training Programme - United Nations Development Programme , 1997, 62 p.)
close this folderPart 2: Emergency telecommunications13
View the document(introduction...)
Open this folder and view contentsFundamental emergency telecommunications concerns
View the documentTypology of telecommunications technologies
View the documentStrategic (worldwide or global) telecommunications systems
View the documentTactical (short-range or local) telecommunications systems

Tactical (short-range or local) telecommunications systems

The table below presents a number of “tactical” telecommunications options for emergency managers who must communicate over short distances (ie, up to 100 Kms.). These are, for the most part, the type of systems needed to communicate with, for example, assessment team members, truck convoy leaders, local counterpart organizations, or on-site field offices.


Note: While satellite communications terminals are typically used for strategic communications purposes, they are also used to great advantage in tactical communications, particularly when the teams communicating are on the move (ie, not communicating from fixed offices.) Managers should, however, be aware of the very high usage costs. For this reason, HF radio is typically preferred when teams are likely to be at a particular site for a while (ie, long enough to set up HF equipment, tune antennas, etc.)

Technology

Advantages

Disadvantages

Inmarsat Standard M or Mini-M satcom terminals

· Chief advantage: Same as above (see strategic communications)
· Useful for tactical telecommunications of emergency teams “on the move”

· Extremely high usage costs

Field Telephones often used in very limited urban area or district

· Chief advantage: Tough, reliable, designed for use under difficult outdoor conditions
· Easy to use network for relatively closely situated telecommunications sites (ie, where wiring will not be difficult)
· Assure privacy of telecommunications
· Readily purchased from army surplus/stores very inexpensively
· Independent of central power system; phone uses long-lasting battery
· Use almost any type of wire for connections
· Not subject to interference or channel overloading
· No licensing needed (don’t use radio channel)

· Wiring needed between telephones
· Unsuitable for mobile system (because of wiring)
· Wiring, as valuable commodity in poor counties, may be stolen

PAX (Private Automatic Telephone exchange) often used in limited urban area or district

· Chief advantage: Easy to use, no training of users
· Dials any telephone connected to exchange
· Semi-permanent installation means best suited for longer-term applications
· Assures privacy of telecommunications
· Fast, reliable communications; not subject to jamming

· Cabling needed; laborious installation
· Can’t access telephones outside of exchange
· Depends upon reliable power
· Not well-suited for fast moving disaster response

PBX/PABX (Private Automatic Branch Telephone exchange) often used in limited urban area or district

· Chief advantage: Same as PAX and connects to Public Switched Telephone Network (PSTN)
· Semi-permanent installation means best suited for longer-term applications
· Can extend reach of Inmarsat or HF radio to other users
· Some weigh only 5 kg; older systems are heavier
· Assures privacy of telecommunications (not subject to being overheard by scanning)

· Cabling needed; laborious installation
· Depends upon reliable power
· Not well-suited for fast moving disaster response

Cordless PBX (Private Cellular Phone System) often used within office compound

· Chief advantage: PAX with little wiring needed for users within coverage area (wiring needed only for base stations)
· Serves as replacement for PAX
· setup speed is faster
· Users have freedom of movement in coverage area

· Range is only about 100 meters from base station; longer range requires setup of additional base stations (one per building floor recommended)
· Permission for frequency allocation is needed
· More expensive than wired lines or walkie-talkies
· Privacy not always assured

Hand-held, two-way VHF radio (also known as “walkie-talkies”) often used over short-distances: several kms

· Chief advantage: Wireless, portable, gives ease of movement



Without Repeater:
· Inexpensive at US$400-700 per radio (complete DHA kit: US$5,000)
· No telecommunications fees
· Portable; hand-held or mobile units (functions well when mobile as larger antennas can be car-mounted and mobile telecommunications are often in open areas; mobile can have up to 25km range)
· Wireless systems; no cabling required (except for trunked or linked repeaters)
· VHF “wireless” LANs available

Without Repeater:
· Range is “line of sight”, ie, depends upon terrain (VHF/UHF waves don’t penetrate thick walls well; never through earth; handheld range may be limited to 2-3 km)
· Must be switched on continuously to hear messages
· Most are Simplex (one way) communications devices; use requires some training
· Regular reliable source of power to charge batteries is needed


With Repeater
· With linked repeaters range of handhelds can be increased greatly (20-50 km and more)

With Repeater
· Raises costs by US$4,000 per repeater station
· If set to work with repeaters, then cannot work without repeaters (batteries, fuel, security of repeaters must be closely monitored; repeaters for dispatch to an acute emergency must have autonomy for at least 48 hours with 50% transmit time)
· Repeater system must be set up by engineers; unsuitable for immediate communications needs

Citizen’s Band Radio (refers to radio frequency band, not equipment) often used over short distances: several kms

· Chief advantage: CB may be the one band common to all agencies working in some areas
· Very low cost ($50 - $100 per unit)
· Works well in gentle, smooth terrain
· Most countries supporting CB have disaster relief networks

· CB illegal in some countries
· CB frequency (27 MHZ) has problems passing through walls and built-up areas;
· Requires heavy antennas
· CB is crowded from overuse; lack of user discipline; jamming is likely
· Repeaters are forbidden as duplex is not allowed

Amateur (Ham) Radio Service used over both short & long distances

· Chief advantage: Local amateurs are generally well-disciplined in radio use, knowledgeable about local conditions, coverage of local repeater system and packet nodes.
· Other advantages: Same as above.
· Amateurs can give good advice about hardware deployment

· Same as in above section on Amateur Radio Service

Q. Consider the tactical telecommunications system employed by your organization. What measures can you recommend to strengthen this system and ensure that, in an emergency, the system will continue to function? What inputs will be needed?




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Needed inputs ________________________________________________
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EXERCISE

Telecommunications barriers in Zenon: The director of the Emergency Preparedness Committee in Zenon has yet to hear from the joint EPC/Red Cross monitoring mission that left three days ago for the refugee camp on the border with Nortenia. The PM has requested an update on the mission’s progress, but so far the EPC hasn’t received a word. He calls the Red Cross.

“Well, all the phones in Montano are down,” the Red Cross director tells him. “Something to do with the rainy season up there. Maybe one of the microwave relays has washed out.”

“But you have radio equipment in the camp, don’t you?” asks the EPC director. “I remember we sent it up from Port Sound. Why haven’t they just called in?”

“Sure, we have short-wave radio up there. Voice and text capabilities. Uses SITOR. Great little package, but I don’t think they know how to use it very well. They haven’t been answering for a couple of days. Or maybe the generator is down again. We had another coming in, but it arrived with our new radio equipment and the documentation for the lot was all wrong. So Customs has the whole shipment locked away at the airport. Power supply, radios, repeaters, the works. We’re waiting for Geneva to straighten out the papers at their end. But I don’t understand. They went in an EPC car. You have mobile radios in all your vehicles, don’t you?

The EPC director pauses. “Well, yes, but...the repeater in Montano is on the blink and there’s no technician available there for another month. So our car is out of range at the moment.”

The Red Cross director sighs. “Well, our shipment should be cleared by the end of the week, I hope.”

The EPC director shakes his head. “The end of the week might as well be a million years away. The PM wants an answer now.”


Q. You are the EPC director. What problems do you face here?




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Q. What preparedness actions should have been taken to minimize these problems?




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Q. What options are currently available to you?




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Q. Where might you turn for assistance if similar problems arose in your own country?




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NOTES
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