Getting the Bay Area transmission facility ready for the spectrum repack that will follow the FCC’s spectrum auction will be one of the trickiest in the country. That’s because of the sheer number of unknowns that must be anticipated and planned for, and the only 39 months the FCC has set in which to complete the work. But the structure’s owners and engineers are planning for all contingencies.
The last time the owner of Sutro Tower, the 977-foot, three-legged broadcast tower that’s home to a dozen over-the-air broadcasters serving San Francisco, had anything like this to deal with was the $14 million renovation completed in 2009 for the transition from analog to digital TV transmission, says Eric Dausman, VP and COO of Sutro Tower Inc.
But even that massive undertaking, involving everything from coverage pattern analyses and replacing antennas, waveguide and associated RF components to mechanical studies and structural enhancements, pales in comparison to what may be required of Sutro Tower because of the FCC’s spectrum auction and repack.
What makes this time around so much more difficult are two factors at odds with one another: the sheer number of unknowns that must be anticipated and planned for and the 39 months the FCC has set in which to complete the work that must be done to repack TV broadcasters into less spectrum.
“Look, we are pretty certain everything will change, but we don’t know what those changes will be, and probably won’t know for certain until probably the middle to late next year after the dust settles from the auction,’” says Dausman, recalling what he told Mark Fehlig, senior engineer, RF spectrum for Cleveland-based Osborn Engineering, the engineering consultancy hired in January to help tackle the planning. “But I can’t wait, so I think we need to have some scenarios established.”
Sutro Tower Inc., is a privately held corporation owned by CBS, ABC, Fox and Media General, and the tower is used by the owners’ local TV stations — KPIX, KGO, KTVU and KRON, respectively. Tenants include KQED, KOFY, KMTP, KCNS, KBCW, KCSM, KFSF and a new TV Azteca repeater station.FM stations and wireless and mobile communications users also reside on the tower.
The scenarios examined for the stations and Sutro Tower vary widely from simple — in which some stations are reassigned to new channels — to calamitous for Sutro Tower. The latter would be if so many broadcasters elect to channel share or simply turn in their licenses, take their payments and go dark that it becomes impossible to sustain operations from an economic point of view, although Dausman describes that possibility as “a tremendous long shot.”
One scenario envisions a couple of existing UHF channels deciding to go back to low-band VHF, says Dausman. In that case, new antennas would be required with their own set of specifications. Understanding the factors like wind load and the impact on the structure of Sutro Tower are essential.
“Likewise, we only have one high-band [VHF] channel on now in San Francisco,” says Dausman. “What happens if one of the stations chose a high-band channel?”
Osborn Engineering’s analysis of the Sutro Tower scenarios has looked at possible antenna patterns and requirements as well as mechanical and structural ramifications of these scenarios, Fehlig says.
The engineering consultancy based its analysis on a hypothetical UHF ch. 29 with a megawatt of effective radiated power. “We analyzed it not knowing who’s on what channel and what the surrounding channels are like, because nobody knows that at this point,” Fehlig says. “We were also very simple in our antenna coverage patterns.”
Other considerations factored into the analysis include the way ATSC 3.0 might ultimately play in the mix when adopted by the Advanced Television Systems Committee and the FCC and how distributed transmission system (DTS) sites might supplement coverage, he says. The engineering consultancy has even gone so far as to examine a future without Sutro Tower.
“The biggest concern is if any of the stations go away — up to half of them may take auction money and run, or channel share,” Fehlig says. “Unlike a shopping center where the shopping center just puts out a ‘space for lease’ sign, this shopping center won’t have anyone interested in the space other than a TV station.”
“Let’s say from 12 to six stations or any combination thereof [throws in the towel or channel shares], the rent of everybody who remains will go up. The yearly maintenance stays the same, but it too would be shared by fewer broadcasters,” Fehlig adds.
All of those factors contribute to a scenario in which it could make better financial sense to discontinue OTA TV transmission from the site and relocate rather than continuing to broadcast from Sutro Tower, he says.
Dausman, who says other broadcasters in the Bay Area may be interested in occupying slots left vacant on the tower by the auction, nevertheless has identified an alternate site in Oakland Hills, Calif., Fehlig says. The location, an old AT&T microwave site, has an existing building “built like a bomb shelter,” that could serve as the transmitter building, he says.
Osborn Engineering has already conducted civil and mechanical engineering surveys of the site and done coverage analysis from the location with various types of antennas and towers. The analysis has also included an examination of FAA compliance and radio frequency radiation studies, he adds.
Dausman emphasizes that such an extreme measure as abandoning the Sutro Tower site is highly unlikely. However, he wants to be ready for any possibility. “We owe it to ourselves to evaluate that as part of any long-term strategic plan,” he says.
While many broadcasters choosing to remain on air will encounter similar challenges as those presented to the owners and tenants of Sutro Tower, few are likely to have as steep a regulatory hill to climb.
Making the changes ultimately required before the FCC’s 39-month repack shot clock expires will be difficult at Sutro Tower because of the “burdensome process” of obtaining the building permits and environmental study reviews, Dausman says. “The last one [tower change] that we just finished took 26 months, and there was very little to no opposition.”
Dausman told the authors of the Widelity Report commissioned by the FCC as much when they interviewed him for their examination of the complexity and cost of the repack nationwide, he says.
The report identified Sutro Tower as one of the most technically complicated sites in nation, and Dausman told the authors that the primary difficulty would be getting building permits to do anything, he says.
Although Dausman has been proactive in laying out possible scenarios stemming from the auction and repack, he has a hard time believing this is actually happening.
“If somebody would have told me in 2009 when we had just finished a $14 million rehab of Sutro Tower that we would be throwing all of that away within 10 years, I would have laughed in his face, taken that bet and been living it big on all of the money I thought I would have made.”