(Satellite Digital Audio Radio Service). The networks operate in a 12.5-MHz band between 2332.5 and 2345 MHz with four of the six radio carriers dedicated to the satellites and the other two channels dedicated to the terrestrial repeaters. Satellites are QPSK to maximise power efficiency. The terrestrial repeaters use COFDM. User terminals have two separate antennas, one for the satellite signals and one for terrestrial signals. The signals are combined in the receiver at baseband using maximal ratio combining. Alternatively, simple voting is used to choose the strongest signal. The receivers tend to be traditional superhets with a 75-MHz IF commonly also used in TV receivers. Antenna systems for these devices are complex ¹0 though the design requirements for receiving satellite and terrestrial signals simultaneously are now well understood. There is a present proposal to deliver more localised services from the terrestrial repeaters. The National Association of Broadcasters in the US opposes this. 16.30 Mobaho in Japan and S DMB in South Korea - S Band GSO Plus ATC Mobaho in Japan and S DMB had a similar network configuration but implemented at 2.6 GHz. A single geostationary satellite covers Japan with a left-polarised beam and S 7 https://www.siriusxm.com/player/. 8 p://www.siriusxm.com/servlet/ContentServer?pagename=Sirius/CachedPage&c=Page&cid=1018209032790. 9 http://www.tvtower.com/xm-radio.html. 10 0http://www.mwrf.com/Articles/Index.cfm?Ad=1&ArticleID=5892. Satellite Networks Korea with a right-polarised beam. A 12.226-GHz transponder on the satellite provides a downlink to terrestrial transponders to provided services in subways and tunnels. 16.31 Terrestar S Band in the US - GSO with ATC Terrestar¹¹ were granted access rights to two by 10 MHz allocations at 2000 to 2020 and 2180 to 2020 MHz. The band is shared with ICO. The launch of the initial Terrestar 500 spot beam geostationary satellite was originally planned for November 2007, but has been rescheduled for September 2008. Terrestar have a joint ve