AM, Wireless Officials Disagree on Interference Test Savings

At issue is what tests a wireless tower within 1.9 miles of an AM directional antenna must run to show it won’t cause more interference by “re-radiating” the station’s signal, said engineers and lawyers from the two industries. To confirm a tower’s interference status, engineers now must do field tests before and after setting up a new tower or significantly altering one already in place. The antenna coalition proposed May 4 that the FCC require wireless operators substitute “method of moments analysis,” a computer modeling technique, for some field measurements. On May 23, the FCC issued a public notice seeking feedback on the group’s plan, an unusually quick turnaround that some said indicates the commission wants quick action on a final rule.

If a tower is found to cause more interference, the wireless operator must spend $10,000-plus installing detuning gear, said engineers. Giving wireless operators a better handle on interference before construction begins would save them money, Benedict said. He predicted more savings if carriers were authorized to model inference via computer rather than having to send teams to measure signals. Under existing rules, interference field tests in remote locales can involve helicopters, ATVs or snowmobiles, said David Schutz, an engineer who appraises radio stations for lenders.

Wireless officials have a different assessment, they said. Today’s test methods let most engineers predict before construction starts whether a tower needs detuning gear, said attorney Paul Sinderbrand, representing the Wireless Communications Association. WCA told the FCC that implementing the coalition plan would “impose unnecessary burdens on wireless broadband providers who deploy or modify facilities near AM systems.” Providers using the lower and upper parts of the 700 MHz band as well as parts of the 2.3 GHz and 2.5 GHz bands could see costs rise, WCA said. The group asked the FCC not to change its definition of what constitutes a wireless tower near an AM transmitter sending signals in several directions, as the coalition wants. The broadcaster group said the FCC should clarify that testing has to be done of any tower greater than 45 electrical degrees in height from a directional antenna, compared with current rules for all towers in a 1.9-mile radius. WCA and PCIA said the change could boost the complexity of compliance for wireless providers. WCA wants the “bright-line certainty” of existing rules to remain, it said. PCIA said current interference test rules apply to public mobile service, advanced wireless service and wireless communications service towers.

The moments method often will add to construction costs by requiring that engineers take a slew of measurements to be fed into computer models to predict interference, said Sinderbrand and engineer Lawrence Behr, whose firm works for wireless carriers. Tower operators could spend $50,000 on a moments method analysis if a nearby AM station lacks signal- strength information, as is often the case, said Behr. “That would very much be a huge disadvantage,” he said. “This would cause a considerable disruption in terms of the present carrier protocols” for signal testing. Field testing a tower now costs a carrier about $6,500, he said. “The cell phone people make a logical argument,” said Schutz. “There is compromise required here.” The moments method could save AM stations several million dollars yearly total, and field tests now cost more than some broadcasters take in during an entire year, he said. “I fear failure to update the operating rules and the cost structure of the AM stations will further accelerate the decline of the AM broadcast medium,” said Schutz.

Wireless officials said it would be a raw deal to force that industry to use the moments method, because the same procedures that save broadcasters cash could cost them money. PCIA said the newer approach could complicate interference testing. “Because the proposed rule does not define the analysis or set forth the underlying assumptions, it is subject to inconsistent application,” said a July 23 filing by the group, which represents companies with over 111,000 towers and antennas. “PCIA suggests that an industry coalition be formed to agree to and craft a best practices document.”

The AM coalition hopes to do just that, Benedict said. Members include Citadel Broadcasting, Clear Channel, Cumulus, Emmis, Entercom and CBS, where Benedict directs spectrum management. Benedict met with PCIA officials before submitting comments to the FCC, and will meet again with them and with WCA representatives before filing replies, due Sept. 7, he said. “We really want this to be a consensus” so it’s a “no-brainer” for the FCC to speed issuance of an order, he said. “Otherwise it will linger for 20 years.” The FCC first addressed the moments method in 1993, delaying action while the testing technology matured, he said. “PCIA is confident that we can reach consensus on this important matter,” said Connie Durcsak, senior director of industry services. Sinderbrand hopes for a compromise, he said. “We're all sort of coming from the same place, which is looking to minimize the regulatory burdens,” he said. “We're hoping to be able to work with CBS and others to achieve what really seems to be a common objective.” - Jonathan Make