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US&R Communications at the World Trade Center
Author: Dan Hudson, WA TF1
Copyright: 9-1-1 Magazine, Feature Content
Originally Published in our Nov/Dec 2001 issue.
The Puget Sound Washington US&R Task Force encountered several communication difficulties during our deployment to the World Trade Center incident. We were deployed at the site from September 19th-29th and spent most of the assignment working in the Church Street Sector or East Branch area of responsibility between WTC Buildings 4 and 5.
Our radio communications were hampered by large city skyscrapers separating the equipment cache, located some 30 blocks to the North at the Javits Convention Center, from the work site at the WTC Complex. Radio relays or repeaters had to be located in close proximity and in a ‘look down’ view at the site to allow for complete coverage within the work zones for all task force personnel.
Our Task Force Communication Technicians, Tim Lenk from Pierce County Department of Emergency Services and Chris Lombard from the City of Seattle Fire Department, were super in their performance in this deployment. They encountered several difficulties in establishing radio relays, including; competing radio frequencies and bands, antenna’s already existing at strategic locations, lightening storms threatening hardware, and simply trying to mount antennas to building structures in positions that would work for both the Base of Operations at Javits and the personnel working at the WTC complex.
Most US&R teams working in NYC divided members into dayshift and nightshift crews. Here, WA TF1 members debrief during a shift change.
Our Search and Rescue components discovered communication difficulties that we had not encountered in prior deployments. As our rescue and search teams moved deeper into the basement levels of the WTC Plaza, radio communication became unreliable and ineffective. Metal girders and beams eliminated or reflected radio signals from deep in the debris field, threatening the safety of our team and creating an accountability nightmare. We had to use the manpower intensive technique of assigning multiple teams of two rescuers to move down through the basement levels to act as radio relay stations for the deepest penetrating team. Though this worked well, it also placed additional rescue personnel in harms way. We later discovered that teams of rescuers moving around the top of the debris field could receive and relay the transmissions from the deepest penetrating team, however we did not experiment with the reliability of such signals always making it to the surface teams. If the radio signals could be reliably received at different locations on the top of the pile, the necessity of sending teams into the pile would be eliminated.
During our Task Force’s after-action debriefings, our communications technicians discussed the use of a ‘leaky coaxial’ cable for deep penetration searches. This type of coaxial cable is utilized in large buildings that have wireless communications or in some inter-urban highway tunnels. The coaxial cable picks up or absorbs radio signals and acts as a detached or passive antenna system. Transmissions sent or being received by teams deep in the debris field near the coaxial would be boosted. A reel of this cable could be simply anchored on top of the debris field and the coaxial pulled partially down into the voids during search operations; at the end of the cable reel, a radio transceiver is mounted to the cable to boost signals moving through it. The cable could then be simply abandoned during the operation to assist with communications from search teams ‘down-under.’ Our future hope is that the ‘leaky coaxial’ will become a standard item carried in our cache.