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Thanks God, yesterday i’ve finished to presented my final project and i got ‘A’ for all my hard work in 3 months. This is a very great news and also a little bad news for me. The great news is, now i’m free until the graduation date. And a little bad news is, i must find a real job for my new life Thanks God, yesterday i’ve finished to presented my final project and i got ‘A’ for all my hard wis, i must find a real job for
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Dielectric Communications has provided antennas, transmission line, and a complete RF system for a new tower site that has brought high-power DTV broadcasts to the Denver metropolitan area. The new installation serves Lake Cedar Group, an organization that represents Gannett Broadcasting-owned KTVD (a MyNetworkTV affiliate) and KUSA (an NBC affiliate), McGraw Hill-owned ABC affiliate KMGH, and CBS owned-and-operated KCNC. The system is currently on air and broadcasting signals for all four stations. “There were a number of technical and logistical challenges that we faced in the design of this system and in obtaining support from the surrounding community, so we’re very pleased to have this transmission site completed and on the air,” said Lake Cedar Group General Manager Don Perez. “We selected Dielectric to provide the antenna and transmission line for this project based on its previous engineering successes, technical abilities, and competitive pricing. We felt confident Dielectric would be a great partner in getting these stations on air with high-power digital transmissions.” This custom-designed RF system with three VHF antennas and three UHF antennas allows six channels to operate in both main and alternate configurations for VHF channels 7 and 9 and UHF channels 16, 17, 19, and 33. Previously, the channels were limited to transmitting low-power digital signals from the tallest building in downtown Denver. By airing signals from the new 730-foot tower located on Lookout Mountain west of Denver, KCNC, KMGH, KTVD, and KUSA benefit from greater transmission performance and streamlined, merged operations that reduce the number of towers visible on the mountain. Unique in its consolidation of several major network broadcasters on a single tower, the installation is further distinguished by the construction of a 250-foot underground tunnel that houses the 10 phased transmission line runs. The tunnel was designed to reduce impact on the appearance of the mountain, maintaining as much of an uninterrupted ridgeline as possible. “Lake Cedar Group had significant technical hurdles to clear in getting this project off the ground, so we’re very pleased to see the project completed with all four stations successfully on the air,” said Dielectric President Garrett VanAtta. “Our engineering staff worked closely with the group to fine-tune the signal patterns and ensure that, even as a consolidated tower site, this installation would meet the individual needs of each member station.”
Key Specifications/Special Features:
Industrial-scale filter dryers, equipped with one or more microwave input ports, have been modelled with the aim of detecting existing criticalities, proposing possible solutions and optimizing the overall system efficiency and treatment homogeneity. Three different loading conditions have been simulated, namely the empty applicator, the applicator partially loaded by both a high-loss and low loss load whose dielectric properties correspond to the one measured on real products. Modeling results allowed for the implementation of improvements to the original design such as the insertion of a wave guide transition and a properly designed pressure window, modification of the microwave inlet\’s position and orientation, alteration of the nozzles\’ geometry and distribution, and changing of the cleaning metallic torus dimensions and position. Experimental testing on representative loads, as well as in production sites, allowed for the confirmation of the validity of the implemented improvements, thus showing how numerical simulation can assist the designer in removing critical features and improving equipment performances when moving from conventional heating to hybrid microwave-assisted processing.
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