NextGen TV: Phoenix Test Of 3.0 SFN Demonstrates Improved Signal Robustness

(Image credit: CTA)

PHOENIX—Single Frequency Network testing of ATSC 3.0 here has proven the efficacy of this multi-site TV transmission scheme in boosting signal level and service margin, significantly improving over-the-air signal-to-noise ratio and ultimately signal reception, according to a newly published report on the latest round of Phoenix Model Market trials.

“Starting in February, we began a series of tests of the Single Frequency Network broadcast from KASW on physical channel 27,” said Pearl TV CTO Dave Folsom.

The primary transmitter site used for the test is located about eight miles south of downtown Phoenix. A smaller transmitter on the same physical channel 27 is located 18 miles away on Shaw Butte, he said.

"[W]e were able to determine the impact of how different power levels and polarizations affect reception and various locations around the Phoenix metro area,” said Folsom.

Testing showed the ATSC 3.0 SFN improved signal robustness. With technical coordination between the two transmitter sites, the SFN was shown “to dramatically enhance what a consumer would be expected to receive,” he said.

Transmission antenna patterns used in the testing deliberately overlapped one another. Signals were timed –in frequency and time—to interfere with one another “in a positive or additive fashion,” said Folsom. The result was improvement in signal level, service margin and receivability where signals overlapped.

“This is the very basis of a Single Frequency Network’s design,” said Folsom. “The improvement translates into a market improvement….”

Improving the additive signal’s SNR component translates into better reception for viewers or increased carriage bandwidth for greater data throughput, he added.

Reception in 40 locations arranged in an approximate grid pattern in the signal overlap area were tested. An omnidirectional test receiver antenna was used to ensure reception would take full advantage of both signals in the overlap area.

When both signals were transmitted, large improvements in signal level and service margin were found at nearly all test locations. Error-free reception was improved in about 80 percent of the sites, the testing revealed.

The test report was compiled by broadcast engineering consultants Meintel, Sgrignoli & Wallace as part of the Phoenix Model Market testing program.

“We believe that broadcast TV has the potential to offer a new data delivery service because of television’s new broadcast standard speaks the same language as the internet itself. A Single Frequency Network arrangement with multiple transmission towers can help broadcasters develop new markets and new opportunities,” said Anne Schelle, managing director of Pearl TV.

The report is available on the Pearl TV website.

Phil Kurz

Phil Kurz is a contributing editor to TV Tech. He has written about TV and video technology for more than 30 years and served as editor of three leading industry magazines. He earned a Bachelor of Journalism and a Master’s Degree in Journalism from the University of Missouri-Columbia School of Journalism.