Clearwire – arguably the world’s biggest service provider proponent of mobile WiMAX technology – yesterday reported a slightly narrower loss for the second quarter and promised strong growth ahead. The company’s 2Q09 net loss was US$73.37 million, a 2 percent improvement on the year-ago period. Revenues were up 9 percent year-on-year to US$63.6 million, driven by 11 percent subscriber growth (Clearwire now has 511,000 subscribers contributing monthly ARPU of US$39.47). It was the potential for future growth that the company was keen to focus on during its earnings announcement. It says it will now cover 25 US markets and a potential 30 million users by the end of this year. “We anticipate fourth-quarter net subscribers additions will be higher than all other quarters in 2009 combined,” said CEO Bill Morrow. Clearwire aims to cover as many as 120 million people across 80 markets by the end of 2010.

Meanwhile, fellow WiMAX supporter Sprint Nextel, the third-largest mobile operator in the US, is expanding its WiMAX service to 17 new cities by the end of the year. Sprint uses the WiMAX network operated by Clearwire, in which it has a majority stake. Sprint claims the network can achieve theoretical peak download speeds of more than 10Mb/s and average downlink speeds of 3-6Mb/s, which it says is “three to five times faster than the 3G service offered by any national [US] wireless carrier today, based on average download speeds.”