Work is scheduled to start on Jan. 19 at One World Trade Center in lower Manhattan on installing a DTV transmission system that will be tested to glean data on signal strength and other characteristics of ATSC signals with the hope of luring back stations that relocated following the 9/11 destruction of the Twin Towers.
The Metropolitan Television Alliance, which represents 12 of the major TV stations in New York City, is planning to test the strength and coverage of broadcast signals from the tower atop One World Trade Center in lower Manhattan, the gleaming new skyscraper that replaced the Twin Towers lost in the 9/11 attacks 13 years ago.
If the tests go well, the MTVA stations may move their primary broadcast facilities to One World Trade Center, which at 1,776 feet is the tallest building in the Western hemisphere.
“There is unanimous interest on the part of everybody,” said an MTVA spokesman who spoke on the condition of anonymity. “We want to know if One World Trade Center will provide a superior place to broadcast from than we have today. Everybody wants to find out.”
Installation of temporary transmission facilities — VHF and UHF transmitters, exciters, rotatable antennas and ancillary RF components — is to set to begin Jan. 19 with testing to commence six to eight weeks after that.
The MTVA comprises the ABC Owned Television Stations (WABC), the NBC Owned Television Stations (WNBC and WNJU), CBS Television Stations (WCBS), Fox Television Stations (WNYW and WWOR), Tribune Media (WPIX), Ion Media (WPXN), Univision (WFUT and WXTV), noncommercial WNET and noncommercial WNYE.
The MTVA stations had broadcast from the north tower of the World Trade Center for two decades. After the 9/11 attacks destroyed the platform, they relocated to other sites. Most now beam their signals from the Empire State Building.
As the new One World Trade Center began rising into the sky several years ago, the Durst Organization, which is managing the building, began trying to lure broadcasters back to lower Manhattan. The stakes are high. According to a 2012 prospectus, owners of the Empire State Building acknowledged that they earned nearly $16 million from broadcast tower leases in 2011.
For its test, MTVA will transmit from One World Trade Center at night on VHF ch. 12 and UHF ch. 32 under special temporary authority granted by the FCC.
Two LPTV stations, which use the channels for normal operations, have agreed to sign off air at night during the test period to support MTVA’s efforts, the MTVA spokesman said.
To collect reception data at various locations, MTVA has equipped a vehicle with a variety of antennas and monitoring gear. For purposes of comparison, the vehicle had already begun measuring reception in various locations from signals from Empire State.
At One World Trade Center, two GatesAir (formerly Harris Broadcast) transmitters, a Maxiva ULXT-10 UHF transmitter with 9 kW of transmitter power output, and a Maxiva VAX-3000 VHF transmitter with 2.25 kW of TPO (shown right), form the heart of the transmission system.
While the GatesAir units will be the first TV transmitters at One World Trade Center, they will not reside in building’s broadcast center on the 89th floor, but rather in a room on the 104th floor, said John Lyons, assistant VP and director of broadcasting for The Durst Organization.
The 17,000-square-foot broadcast center has not yet been completed, he said. When it is, it will be able to accommodate up to 11 TV and 21 radio stations.
Radio Frequency Systems, with regional headquarters in Meriden, Conn., is supplying circular-polarized VHF and UHF antennas for the test. The VHF antenna will deliver 5 kW effective radiated power, while the UHF antenna will transmit 230 kW ERP, the MTVA spokesman said.
To economize for the test, only single sections of antenna will be mounted to the tower. The UHF section will be mounted below the beacon at the top of the spire and the VHF section below the UHF antenna. Both antennas will be aimed north in the same direction as the Manhattan avenues.
“The antennas are going to be gimbal-mounted so we can swivel them around, and we can test various azimuths,” said Lyons.
No definite date has been set for completing the test; however, once MTVA has all of the data it needs the transmitters, antennas and other RF components supporting the effort will be removed from One World Trade Center, Lyons said.
MTVA’s test comes as the broadcasting industry works on new digital TV broadcast standard through the Advanced Television Systems Committee dubbed ATSC 3.0.
While MTVA will confine its test to the current ATSC 1.0 standard, and even exclude transmitting and analyzing a mobile DTV (A/153) signal, it may also provide useful information on how ATSC 3.0 signals from One World Trade Center may perform, said Rich Redmond, GatesAir chief product officer.
Multipath resulting from signal reflections off buildings and terrain is “somewhat independent of modulation” (single carrier ATSC vs. multicarrier OFDM), Redmond said.
For now, the focus is on data that will help stations determine if they can improve delivery of their over-the-air signal today by relocating to the new site. “What we are doing as MTVA is collecting data,” said the alliance spokesman. “How a station decides to use that is up to the individual station.”
However, the test is bringing a bigger picture into focus, said Redmond. The intense interest in understanding market coverage from One World Trade Center is indicative of how important over-the-air transmission is to TV broadcasters and the lengths to which they will go to ensure they deliver a superior signal, he said.
“This interest underscores the importance of wireless, free-to-air broadcasting and its place in the media landscape,” Redmond said. “These are top performing broadcast stations, and they are looking really hard at what is the best site to transmit from to maximize their coverage.”