Whitepapers

Analysis of Antenna Beam-tilt and Broadcast Coverage

Antenna beam tilt affects areas covered by strong signals. Improvements greater than 10dB are realized using greater beamtilts offered in end-fed arrays.

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Analysis of Antenna Climbing Equipment

Antenna climbing systems are compared. Dedicated, separate climbing ladders are found to have superior safety and reliability characteristics.

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Analysis of Antenna Null-fill and Broadcast Coverage

Antenna pattern characteristics of end-fed and center-fed arrays are discussed. End-fed arrays are found to have improved null-fill and coverage.

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Analysis of Dual-Channel Broadcast Antennas

The design concept is discussed for slotted UHF antennas that allows the combining of a high power NTSC channel with an adjacent DTV channel assignment using a single transmission line and antenna.

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Analysis and Measurement of RF System Reflections and DTV Transmission

Terrestrial digital television (DTV) broadcast employs complex transmission facilities composed of filters, diplexers, transmission line components, and antennas. The reflections introduced by these components are minimized by broadband design methods, and the nature of the total reflection as these components are combined into a system is developed. The radio frequency (RF) transmission line, immitance, and network parameters used to characterize these systems (i.e., voltage standing wave ratio or VSWR) are related to key DTV performance parameters.

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Analysis of Pressurized Radome Enclosures

Enclosures are discussed for the protection of antenna equipment in extreme environments.

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Analysis of Smooth Patterns and Broadcast Coverage

Antenna pattern characteristics of side-lobe level and null-fill are compared. The application of smooth, null free patterns is discussed.

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Antenna Contributions to Amplitude and Phase Variation Across a Broadcast Channel

Antenna amplitude and phase patterns, differential amplitude, differential phase, and group-delay are compared for end-fed and center-fed array configurations.

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Antenna Pattern and Coverage Optimization

Antenna patterns of end-fed and center-fed antenna arrays are compared. Coverage improvements are produced by end-fed array elevation patterns.

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Array Antenna Pattern Measurement Techniques

Antenna patterns are measured using two independent methods and compared. Excellent agreement between far-field measurement and measurements from anechoic chamber and nearfield techniques.

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High Level IBOC Combining Methods for Single Input Antenna Systems

Combining separate analog and HD Radio FM transmitters into a single antenna allows broadcasters to use existing equipment including transmitters, transmission line, and antennas; however, the options for accomplishing this are limited. A new method of high level analog/FM HD combining is discussed and compared to the other traditional methods.

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Slotted Coaxial Arrays Provide Lightweight, Economical Antenna Alternatives to Panel Arrays

Antenna patterns and reliability of UHF slot array and panel array antennas are compared.

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Transmission Line for Broadcast Applications

The major design criteria for standard broadcast transmission lines and their correlation to published specifications are detailed. Technical performance and applications for DTV are outlined.

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Waveguide for TV Broadcast

Properties of circular waveguide are discussed with application to UHF TV broadcast systems. Mode filtering pins are introduced to eliminate cross-polar and higher order modes.

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