EL SEGUNDO, Calif. (Reuters) - Hughes Electronics Corp., owner of the DirecTV satellite television network, on Tuesday reported a third quarter net loss of $29.6 million as high acquisition costs and other expenses offset robust growth at DirecTV.

Third quarter revenues at Hughes, a unit of General Motors Corp., rose 31.5 percent to $1.99 billion from $1.51 billion a year ago.

After higher amortization and depreciation costs for acquisitions, increased net interest expense and higher costs at its PanAmSat group, Hughes posted the third quarter net loss that equaled 13 cents a share vs. a profit of 11 cents, or $42.9 million excluding adjustments, in last year's third quarter.

Earnings before interest, taxes, depreciation and amortization, however, were up 18.3 percent to $211.6 million vs. $178.8 million in last year's third quarter. Such earnings are a standard measure of performance in capital-intensive businesses like satellite services due to the large amounts of non-cash expenses such as amortization and depreciation of assets.

Hughes stock was off $1.25 at $64 by midday on the New York Stock Exchange, hovering below its year high of $69.25.

In a statement, Hughes stressed its gains in revenue and cash flow saying it had its best quarter ever for subscriber growth at DirecTV, which helped drive the gains in underlying earnings.

``We have reached the point where the EBITDA (earnings before interest, taxes, depreciation and amortization) generated by our large subscriber base is outpacing the marketing costs (of) our record subscriber growth,'' said Chief Executive Michael Smith. ``We expect our U.S. DirecTV business to continue to deliver positive EBITDA that accelerates yearly.''

DirecTV added a record 423,000 net new subscribers to its high-power service in the quarter, a 40 percent jump from the 303,000 net new subscribers added in the third quarter of 1998.

In addition, 204,000 customers replaced their medium-power service provided by Primestar, a satellite TV operator that Hughes acquired earlier this year, with DirecTV's high-power service. As of Sept. 30, DirecTV had more than 7.7 million subscribers including roughly 1.8 million Primestar customers.

Third quarter revenues for DirecTV's broadcast, leasing and other services rose to nearly $1.3 billion vs. $640 million last year. Revenues in its product sales segment fell, however, to $696 million in the third quarter from $872 million.