had their antennas. All were lost when Twin Towers One and Two collapsed after the September 11 attacks in 2001. Most of those stations reverted to broadcasting from their previous home, 200 feet lower, on the Empire State Building. Objections Antenna farms have often been the source of complaints from local neighborhoods, particularly when a new tower is added. This has been increasingly so for TV stations, which have been pursuing with alacrity the construction of new digital television antennas. Because many of these towers are already full, or were built well before there was the expectation of DTV, many stations have been forced to go through the even greater expense of constructing a new tower. One such situation was in Colorado, in the late 1990s and early to mid-2000s. Many of the Denver metropolitan area TV stations already transmitted analog TV from Lookout Mountain, but needed the extra space for more antennas. Additionally, since many people live on Lookout Mountain, there was also the concern about safety, not only from falling ice or even the slight risk of a tower collapse, but also ongoing from the additional RF that it would create. Residents and the city of Golden filed legal objections, including challenging the authority of the Federal Communications Commission (FCC) to override denial of zoning permits by local government (in this case, the Jefferson county commission). The city of Golden also sought to condemn the site, even though it was outside city limits. It was decided that scenic Eldorado Mountain near Boulder might be a better site, but there were also objections that it would ruin the view of that mountain from the valley. Despite other alternatives, the new "supertower" was forced on Lookout Mountain by the U.S. Congress, allowing the existing towers to be removed in 2009 after analog shutdown. The site began operating in spring 2008. Antenna farm requirements Clear line of sight, especially for microwave dishes Free of radio interference, such as marine radar Higher ground elevation, to maximize coverage Away from high-rise structures and other obstructions Must be at least 20 miles away from airports Antenna farm staff RF engineers Broadcast engineers Air conditioning engineers (to maintain the cooling systems associated with high-powered transmitters) Electrical engineers (for power systems) Maintenance, repair and operations technicians Telecommunications facility manager Security guards See also Antenna array Earth station Echelon (signals intelligence) References Antennas (radio) Telecommunications equipment Broadcast