K1DFT made today's New York Times. Dave K1ZZ Intriguing the Physicists, Radio Buff Shrinks an Antenna June 10, 2004 By IAN AUSTEN WHILE a lifetime in ham radio played a role, it was love that ultimately led Rob Vincent to develop what he says is a way to make antennas significantly smaller but still efficient. "About 1995 I had met a sweetheart and we fell in love," Mr. Vincent, now 60, recalled. "I went to live with her, but the only problem was that she lived on this postage stamp of a yard in a congested neighborhood." The real estate owned by Carolyn Hardie, the woman Mr. Vincent later married, was an issue because his amateur radio interests had turned toward frequencies in the 160-meter band. That band is close to broadcast AM radio. And, like an AM station, operating on it requires a tall antenna - in Mr. Vincent's case, one that is 140 feet high. Aesthetic and zoning questions aside, the 50-by-100 foot lot was not big enough to accommodate the guy wires needed to stabilize a tower that high. So Mr. Vincent, a technician with the University of Rhode Island's physics department, began thinking about ways to make antennas smaller. The end result is a system that he claims can produce antennas that are one-third to one-ninth as high as normally required. He has spoken to other ham operators in over 80 countries on the 160-meter band through his relatively new, self-supported backyard tower, which is one-third of the conventional minimum size. Mr. Vincent said his improvements were not just applicable to ham radio towers. They could be used to either further shrink the tiny antennas in cellphones, he said, or boost their efficiency. Small yet efficient antennas have long been a goal for radio researchers, said R. Dean Straw, the senior assistant technical editor for the American Radio Relay League, an association of amateur operators. "The holy grail is an antenna the size of a grain of salt that produces big signals," he said. Generally the size of antennas increases with the wavelength of the frequencies they are transmitting or receiving. While there are several formulas for determining optimum height, the height of most antennas is one-quarter to one-half the wavelength. At 140 feet, for instance, Mr. Vincent's ham tower would have been slightly higher than one-quarter of the wavelength of 160 meters, which is equal to 525 feet. Smaller antennas can be used, but with a trade-off. "When you get below a quarter-wavelength, efficiency drops off dramatically," Mr. Vincent said. Before arriving at the university in the early 1990's in a still-unfulfilled quest to complete his undergraduate degree, Mr. Vincent spent about 30 years in radio-related engineering jobs, mostly with a radar division of Raytheon. But his tinkering with antennas dates back to when he obtained his first amateur radio license at the age of 14. "I've always had a natural understanding of radio - maybe it's from a prior life," Mr. Vincent said. "But in those early days I could not fathom how an antenna worked." The relationship between antenna height and efficiency was so well established that he initially kept his antenna-shrinking work a secret. Mr. Vincent also acknowledged that he had relatively little idea of what might work when he began the project. "When I started out to do this it was 10 percent theory and 90 percent black magic," he said. After reviewing much of the literature, Mr. Vincent started designing antennas with special simulation software on a personal computer.

From the most promising of those virtual designs, he ran tests using antennas that were about 18 inches high and fashioned from copper-covered Plexiglas rods. One model seemed particularly successful until it lost its signal during a high-powered broadcast test. When Mr. Vincent went outside, he found only a lump of molten metal and plastic.

Gradually, he said, potential areas of improvement became apparent. He began confiding in some friends from the ham radio world and faculty members in the physics department. One friend allowed Mr. Vincent to build a 46-foot-high experimental antenna at his country home, which includes a salt marsh. Saltwater is an antenna builder's dream. By providing a highly conductive base for the antenna, the water improves reception. The big prototype improved upon conventional designs in many ways. But one crucial one involved the placement of devices known as load coils along its length. Load coils are commonly used in cellphone antennas to alter their current patterns. Conventional broadcast antennas, Mr. Vincent said, generally have a lot of current at the bottom and very little if any at the top. With his design, current is more evenly distributed. To avoid suggestions that saltwater, not his design, was the magic, another 46-foot prototype followed, built on rock. It offered 80 to 100 percent of the efficiency of an antenna three times its size. About three years ago, the University of Rhode Island became interested enough in Mr. Vincent's work that it gave him office space. After a review by engineering and physics professors, it began the process of patenting and selling the technology. Mr. Vincent has turned over all his rights to the university. "We've seen test data from Rob Vincent and it sure is attractive," said Quentin Turtle, the director of industry research and technology transfer for the university. Mr. Straw of the radio relay league said he was impressed with Mr. Vincent's work ethic. "But I remain somewhat skeptical,'' he said. "I'd like to see some validated field test measurements." Mr. Vincent said he was aware that would-be buyers of his technology would demand better test results, although measuring the efficiency of antennas is difficult. But given the scrutiny his project has received to date, he said he was confident that his antennas would pass muster. "I'm part of the technical staff to a whole bunch of Ph.D's," he said. "You can't fool these people." http://www.nytimes.com/2004/06/10/technology/circuits/10next.html?ex=1087872... For general information about NYTimes.com, write to help@nytimes.com. Copyright 2004 The New York Times Company