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Dielectric says it’s bringing the high-efficiency and low windload reliability of its broadband pylon TV antennas to FM broadcasters. It is introducing new FMP antennas, which, it claims, represent the broadcast industry’s first slot cavity microstrip FM antenna product family. The company says the new antennas will bring novel benefits to high-power FM broadcasters. These include multicasting, pattern flexibility, increased reliability and a small tower footprint. It will share full details of the FMP family for the first time at the forthcoming NAB Show at the Las Vegas Convention Center, April 23–27.
“Television broadcasters have long valued pylon antennas for their straightforward designs, versatility and structural benefits such as low wind load,” said Keith Pelletier, vice president and general manager of Dielectric. “The cylindrical design attributes of pylon antennas historically translated to narrow bandwidth characteristics that were impractical for FM signals. Dielectric’s engineering breakthroughs introduce techniques to increase that bandwidth, making full-band FM operation in pylon antennas a reality.”
The FMP family carries over many traditional pylon antenna benefits, including optimal downward radiation, smaller size and lower weight
The company states that engineering breakthroughs include reducing the antennas’ Q factor, which improves the bandwidth from 1% to 20%, and stabilizing the H:V ratio across the band. The 20% bandwidth translates to full FM band operation, which, Dialectric says, is the key goal of the FMP antennas’ design. The new antennas include Dialectric’s patented parasitic dipole, which adds a vertical component to the existing horizontal signal. This creates more pattern options for FM broadcasters — including elliptical and circular polarization — and contributes to the substantial bandwidth increase.
Adaptation and simplification
While Dielectric’s special pylon designs for FM radio differ from TV systems, it says the FMP family carries over many traditional pylon antenna benefits, including optimal downward radiation, smaller size and lower weight. For example, FMP antennas reduce the number of parts used in equivalent ring-style antennas by more than 60%. The streamlined componentry also improves reliability over the long term as there are far fewer parts to repair or replace.
The pylon design also provides broadcasters and tower crews with top-mounting options, in addition to the traditional side-mounted configurations of ring antennas. This would be ideal for high-power FM stations that want a true top-mounted omnidirectional antenna. Dialectric claims the FMP can handle input powers of 100 kW and higher, which would make the antennas excellent for the combined operation of multiple stations.
“We are always looking at ways that we can bring antenna design concepts from one market to another and advance the technology for modern and future broadcast systems,” said Pelletier. “We have now adapted what was long a solution for mostly single-channel TV operations for both broadband TV and FM broadcasting, which very much differentiates our product portfolio from competitors.”
Dielectric will be at booth W7107 at the NAB Show 2022.