Friday, May 18, 2007
A COW That Doesn't Produce Milk
When is a COW not a cow?
When it is a portable cell site. Many municipalities use "cows," or cellular-site on wheels, to establish temporary coverage for an area, or to augment the coverage for a special even when call-volume loads would be higher than normal. A typical "cow" consists of a 30' to 100' telescoping monopole, equipment cabinets and power generator--all mounted to a trailer (see photo). In October of 2003, when the Cedar fire destroyed much of the communications infrastructure in San Diego's East County, a number of private carriers, working with local government, brought in COWs to establish emergency cellular service for the firefighters and emergency-service personnel. Companies like the Avisar Group (www.avisargroup.com) have developed their own market niche by providing truck and trailer-based cell sites to public and private agencies.
Sometimes, a COW can be a COLT. COLT stands for cellular-site on a light truck (or van) and were critical in providing communications for portions of New Orleans following Hurricane Katrina, and in lower Manhattan in the aftermath of 9/11. Missouri and Kansas currently have an agreement in place with a local cellular-phone provider to provide COW services in the event of an emergency. Under this agreement, the carrier could augment or replace damaged communications lines with their portable trailers in less than 24 hours. This type of public-private partnership is being considered in several other budget-strapped cities faced with the challenge of upgrading older emergency-communications equipment, but lacking the funds for permanent installations.
In 1998, when Puerto Rico was hit by Hurricane Georges, more than 490,000 landlines were down or had no intra-island long-distance service. CellularOne Puerto Rico, one of three wireless carriers serving the island, reported that by the next morning after the hurricane, more than 85% of their wireless network was damaged. However, by using COWs, the carrier had 75% of their network back online in three days, and 90% in less than a week.
As Chris Wilson reports in an April 17 article for US News and World Report, man-made tragedies like the Virginia Tech incident can also strain a local wireless network, as frantic phone calls flood into and out of the system. Wilson writes that "companies build enough technical capacity into their systems for only a 2 percent increase over normal levels before calls start getting dropped."