New York - Oct 18, 2010 - The master antenna system mounted on the Empire State Building suffered a major lower bay failure on Oct. 18, 2010. The antenna system uses two bays. The lower bay had some damage that was temporarily repaired on Oct. 17, but the repair did not hold. The group that maintains the antenna determined the upper bay to be in good working order, and recommended to the users that they reduce power to 50 percent and use just the upper bay. All the tenants agreed. The reduced-power operation began at 10:35 p.m. on Oct. 18. Some stations have back-up facilities at 4 Times Square and used those facilities instead.

At 12:35 a.m. on Oct. 19, all broadcast stations (including TV) either shut down or transferred operations to 4 Times Square. The master combiner was then switched to feed the backup antenna. (The back-up, referred to as the Alford antenna, was the first master combined antenna installed in 1959. It was manufactured by the Alford Manufacturing Company.) The goal was to remove the damaged line and possibly replace it with a temporary section from the master FM (MFM) combiner room. After further inspection, the power divider on the combiner was also removed for inspection. The crew spent the evening removing the power divider and transmission line and weatherproofing the feeds to prevent moisture ingress.

The damaged units were removed to the 103rd floor for inspection.

Connection on the power divider

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Burned transmission line

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Burned power divider showing the hole through the sidewall.

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Burned output port of the power divider

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Repairs for the power divider and transmission line are underway.

The decision to use half the ERI antenna rather than the Alford back-up antenna during the repairs is based on two factors. The ERI antenna has better coverage than the Alford antenna, which has some nulls in coverage. Also, the Alford antenna affects the Empire State Building's Observation Deck operations.