Communications Satellite Corp. profits soared 54 percent in the first quarter-leading to decisions to increase dividends and reduce rates for international services.

The Washington firm said yeterday that earnings in the January-March period were $11.9 million ($1.49 a share) compared with $7.8 million (97 cents) in the 1978 period as revenues rose $11 million to $60 million.

After studying these gains, Comsat's directors voted yesterday to boost the quarterly dividend rate to 57 1/2 cents a share-up 15 percent from the previous payout of 50 cents a share. The first dividend at the higher rate will be distributed June 11 to owners of record May 11.

Comsat President Joseph Craryk also announced a 15 percent reduction in rates for international communications satellite channels.

He pointed out that growth in Comsat's traffic through the Intelsat global satellite system has contributed significantly to the earnings increases and noted that the larger volume of traffic allows Comsat to offer the lower rates.

"We are particularly pleased, especially in these inflationary times, to be able to continue the pattern of decreasing costs and rates," Charyk added.

Comsat said the lower rates will apply to satellite channels leased to the company's international common carrier customers in the U.S. for voice, data and video services.

Equitable Bancorporation of Baltimore, holding company for Equitable Trust Co., reported a 21 percent increase in first-quarter profits.

Not counting securities sales, Equitable earned $3.3 million (92 cents a share) compared with $2.8 million (76 cents) in the same 1978 period.

Chairman Owen Daly II attributed the gain primarily to strong loan demand and continued high interest rates on those loans. Average loan volume rose 17 percent to $1.29 billion while total deposits jumped 13 percent to an average of $1.66 billion in the recent quarter.

Equitable directors also declared a quarterly dividend of 17 cents a share, payable June 30 to owners of record June 15.

CACI Inc., an Arlington-based professional research analysis and programming firm, reported earnings of $841,310 (82 cents a share) for the nine months ending March 31 compared with $359,738 (35 cent) for the nine months of the previous year.

The firm also reported revenues for the past nine-month period of $13.7 million compared with $9 million for the first nine months of the previous year.

The company did not report third quarter results.