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It was debunked Jim...
The test antenna was a 7MHz monopole, 50% of the normal quarter-wave size. Now one thing from an illustration that begs more information was the ground system. It shows 150' radials, which appear to terminate at the sea water's edge. There is about a mile of seawater between the test antenna and the calibrated receive antenna.
The article concludes; "Vincent's antenna designs were tested using the official regime the Navy uses to certify antennas. Vincent's Plano Spiral Top Hat antenna, at 7MHz, was shown to have equal sensitivity to a normal quarter-wave antenna but at 50% the quarter-wave unit's size. In addition, bandwidth of the Vincent design was nearly twice as wide as that of the quarter-wave unit."
The initial Vincent claim read almost like CFA, CTHA, Fractal, and E-H antenna claims. A very short antenna with makeshift construction was claimed to produce better than full size performance. The claims have evolved now to 50% shortening over a nearly perfect ground produces equal FS.
The difference in FS between a conventional 1/4 wl tall antenna and a 1/8th wl tall antenna is within measurement error when the antenna is over a very good ground system and when it uses a good loading inductor regardless of where loading is placed. Brown, Lewis, and Epstein knew that in the 1930's.
As a matter of fact even with a loading coil Q as low as 250 (typically like air core #16 wire) and using base loading there is less than 1dB difference between a 1/8th wave and quarter wave antenna!
The apparent endorsement of the DLM antenna by the U of RI does prove one thing....we need to work on our educational system and stop the backslide in science. The U of RI and Vincent are now at the level of early 20th century antenna
technology.
73 Tom, W8JI
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