To: kovachs who wrote (5377 ) 10/21/2006 12:24:45 PM From: pcstel Read Replies (1) | Respond to Here is what the Federal Communications Commission stated when they granted the modification to SIRI Space Segment. </i? The HEO design engendered numerous benefits to the listening public. First, the system improves service to subscribers in the northern United States by increasing the elevation angles to the receivers. Sirius’ originally proposed geostationary system would have served the northern third of the United States at an average elevation angle of 30 degrees. The HEO design ensures that at least one satellite is available at all times in this area to provide service at an elevation angle near 60 degrees. The higher elevation angle reduces path loss, lessening vulnerability to signal blocking, from buildings and terrain, and lowering susceptibility to shadowing and fading caused by trees and foliage. Second, the improved propagation and increased margin resulting from HEO configuration allows Sirius to offer more channels within its existing spectrum allocation for any given satellite power.33 Finally, the improved elevation angles, and thus performance, of the HEO system narrow somewhat the size of expected “gaps” in satellite coverage. As a result, the HEO system makes FEWER repeaters necessary to serve mountainous and urban areas, especially in the northern continental United States. By way of comparison, Sirius currently operates about 140 TERRESTRIAL repeaters, while XM’s geostationary system is augmented by over 800 TERRESTRIAL repeaters, or five times as many as Sirius.
