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1 <br /> 6.2.5 Television and Radio Interference <br /> Corona from transmission line conductors can generate electromagnetic "noise" at the same <br /> t frequencies that radio and television signals are transmitted. This noise can cause interference with <br /> the reception of these signals depending on the frequency and strength of the radio and television <br /> signal. Tightening loose hardware on the transmission line usually resolves the problem. <br /> If radio interference from transmission line corona does occur, satisfactory reception from AM <br /> radio stations presently providing good reception can be obtained by appropriately modifying (or <br /> ' adding to) the receiving antenna system. Moreover,AM radio frequency interference typically occurs <br /> immediately under a transmission line and dissipates rapidly within the right-of-way to either side. <br /> FM radio receivers do not usually pick up interference from transmission lines because: <br /> ' • corona-generated radio frequency noise currents decrease in magnitude as the frequency <br /> increases and are quite small in the FM broadcast band (88-108 Megahertz);and <br /> a • the excellent interference rejection properties inherent in FM radio systems make them <br /> virtually immune to amplitude-type disturbances. <br /> ' A two-way mobile radio located immediately adjacent to and behind a large metallic structure (such <br /> as a steel tower) may experience interference. Moving either mobile radio so that the metallic <br /> structure is not immediately between the two units should restore communications. This will <br /> generally require a movement of less than 50 feet by the mobile radio adjacent to the metallic tower. <br /> Television interference is rare but may occur when a large transmission structure is aligned between <br /> ' the receiver and a weak distant signal, creating a shadow effect. Loose or damaged transmission line <br /> hardware may also cause television interference. <br /> ' Digital reception is,in most cases, considerably more tolerant of electric interference and somewhat <br /> less resistant to multipath reflections. In the digital realm, the picture does not gradually degrade; <br /> rather,at what is called the"avalanche point," the picture suddenly pixelates (turns into squares) and <br /> usually"freezes." <br /> Mitigative Measures <br /> ' No impacts are anticipated from the proposed Project. However, if radio or television interference <br /> occurs because of the transmission line, Xcel Energy will work with the affected parties to restore <br /> reception to pre-Project quality. If the interference is due to the power line, the electric utility will <br /> remedy problems so that reception is restored to its original quality. Generally, the problem is <br /> resolved by moving or raising or adjusting the customer's antenna. In some instances, a more <br /> 1 effective antenna or a signal amplifier is required. <br /> 6.2.6 Aesthetics <br /> ' The proposed substation replacement will be within existing Xcel Energy property and the <br /> transmission facilities will mainly follow existing BNSF railroad and U.S. Highway 12 rights-of-way. <br /> The Project will have some effects on the visual and aesthetic character of the area. <br /> I <br /> ' Orono Project June 7,2011 <br /> MPUC Docket No. E002/TL-11-223 45 <br />