Commercial wireless carrier Sprint Nextel this week reported a $1.6 billion loss during the fourth quarter of 2008, when the company also lost 1.3 million subscribers, most of which had been customers of the company’s services offered over its iDEN network.

According to Sprint Nextel press releases, the carrier had 12.4 million customers on its iDEN network at the end of 2008, a decrease of 1.1 million customers compared to the previous quarter. The fourth-quarter figure is a 33.4% decrease from the number of customers served by the iDEN network during the third quarter of 2007.

To take advantage of this excess capacity on the iDEN network, Sprint Nextel has announced plans to refocus efforts on marketing its Boost Mobile prepaid commercial offering on the iDEN network, Sprint Nextel CEO Dan Hesse said during a conference call with analysts on Wednesday that was webcast.

Hesse said the marketing of the Boost Mobile offering would be heavier in areas of the country where there is more excess capacity on the iDEN network. Currently, performance on the iDEN network is at all-time highs, and the carrier does not want to jeopardize that performance, he said.

“We will not let service levels for our iDEN customers be impacted in any way,” Hesse said. “We are watching the performance of the iDEN network very closely.”

Many public-safety agencies use the iDEN network—best known for its industry-leading commercial push-to-talk service—to complement their LMR communications. Hesse said performance on Sprint Nextel’s CDMA and iDEN networks is very high, but the carrier is having difficulty changing the perceptions of the enterprise market, which was very critical of poor performance metrics during 2007.

In other public-safety-related news, Sprint Nextel CFO Bob Brust said funding the 800 MHz rebanding effort now costs the carrier about $200 million to $300 million per quarter, but noted that those figures can fluctuate based on the progress that is realized in the reconfiguration effort.

Brust said Sprint Nextel has been improving its cash position, boasting $3.7 billion in the bank and retiring $1 billion in debt. With the implementation of cost-saving strategies such as a reduction of 8000 employees, the company expects to generate free positive cash flow this year, he said.