Communications Satellite Corp. yesterday reported a 17.4 percent increase in profits for 1979 despite a drop in profits for the fourth quarter.

Comsat, the Washington-based communications firm, reported profits of $40.1 million ($5.02 a share) for 1979, up from $34.2 million ($4.28) in 1978.

But for the fourth quarter of last year, Comsat showed a profit of $7.5 million (94 cents), down from 1978 profits for the same period of $9.7 million ($1.22).

The fourth-quarter results were attributed to several reasons including the reduced use of one of Comsat's systems by the U.S. Navy. But 1979 revenues increased sharply, jumping to $262.6 million from a 1978 figure of $211 million.

Government Services Savings & Loan reported its third straight quarter of declining profits.

The second largest state insured savings and loan institution in Maryland, Government Services reported profits for the third quarter of its fiscal year totaling $145,645, down from a figure of $694,000 for the third quarter of last year.

Further, Government Services' nine-month profits totaled $741,210 (87 cents a share) compared with nine-month profits last year of $2.1 million ($2.54).

But the savings and loan also reported that assets as of Dec. 31 grew to $331.9 million from $319 million a year ago.

A company spokesman attributed to the decline to the earnings squeeze on the entire thrift industry and said the company was also showing a predictable decline in mortgage loans.

Nevertheless, Government Services, now with seven branches, including two opened in December, also announced that it has applied to open an eight office in Hyattsville.

The spokesman said Government Services, advertising program, promoting a seven percent passbook interest rate and other new offerings, and good results from January deposits were also encouraging.

In another report, Planning Research Corp. reported a slight increase in profits for the six-month period ending Dec. 31 despite a drop in total revenues for the same period.

The information and consulting firm reported six-month profits of $2.95 million (43 cents), a slight increase over last year's figures of $2.91 million (42 cents). Revenues for the same six-month period dropped two percent from the same period last year to $127.2 million. elines. No one really knows when, if ever. Alaskan natural gas will re