The University of the District of Columbia's popular all-jazz radio station has been sold for $13 million to C-SPAN, which stepped in at the last minute to buy WDCU-FM after a religious broadcaster backed out of the deal, C-SPAN officials said yesterday.

C-SPAN, the cable network that covers Congress and is owned by the nation's cable television stations, will change the format of the station by about Oct. 1 to public affairs -- 24 hours a day, seven days a week, the officials said.

"There won't be any commercials, and there won't be any auctions, and there won't be any on-air pitches for money," said Brian Lamb, C-SPAN's chief executive.

Lamb said he does not expect any problems in getting the Federal Communications Commission, which must approve all license transfers, to agree to the sale.

UDC, under orders by the D.C. financial control board to close a $10.1 million budget gap by Sept. 30, has been trying for months to sell Jazz 90 -- which has the fourth-largest black audience of any noncommercial radio outlet in the country.

In June, UDC signed a contract to sell the station to a nonprofit group associated with Salem Communications, one of the nation's largest commercial Christian broadcasters. But opponents threatened to hold up the purchase in the FCC, arguing that a commercial religious broadcaster would not fit into the definition of a noncommercial licensee.

FM frequencies below 92 on the dial are reserved for noncommercial, educational broadcasting.

According to sources involved in the deal, Salem decided not to buck the opposition and asked C-SPAN if it wanted to buy the contract for the same amount of money it had offered. C-SPAN, which had been runner-up bidder with an offer of $10.5 million, agreed to pay $13 million.

UDC Acting President Julius Nimmons Jr. said he had heard about the change in purchasers and had been assured the school would get its money by the end of the fiscal year.

However, Andy Schwartzman, executive director of the Media Access Project, a public interest law firm that has fought to save WDCU's jazz format, said he is no happier with C-SPAN's purchase of the station.

"This is not a satisfactory resolution," he said.

Lamb said that he understood why jazz fans were unhappy but that C-SPAN has its own agenda.

"It's unfortunate, and I think it's not our responsibility, to be honest," he said yesterday. "The university is selling this radio station. They need the money badly. We feel among other things that we've done our bit in this by providing the $13 million on schedule so the university can stay open. It's not a pleasant day for somebody who loves jazz."

The purchase by C-SPAN marks the network's first entry into radio. Lamb said C-SPAN did not anticipate buying other radio stations across the country but would franchise its format to existing stations.

The sale of Jazz 90 has caused great unhappiness at the university, where the station was a source of pride. Trustees who approved the sale said there was no other way to close the budget gap. Staff writer Marc Fisher contributed to this story.