Reprinted from yesterday's late editions.

Chicago's Tribune Co. Wednesday announced an agreement in principle to buy WDCA-TV, Channel 20, a Washington independent station founded in 1966.

Pending approval by directors of Tribune Co. and Superior Tube Co., which owns Channel 20 Inc., financial details of the proposed transaction were not disclosed.

Superior, a Pennsylvania manufacturer of precision tubing, purchased WDCA in 1969 for $2.2 million from Capital Broadcasting Co., which was headed by Milton Grant.

Among local commerical stations, Channel 20 generally has been at the bottom of Nielsen ratings with programming that consists mostly of situation comedy re-runs, old movies and sports. There also are some lowbudget station-produced programs.

One of the largest communications companies under private ownership, Tribune Co. owns the New York Daily News, the largest circulation daily in the country, as well as The Chicago Tribune, two newspapers in the Ft. Lauderdale and Orlando areas and a growing string of dailies, weeklies and Free-circulation "shoppers" in California.

Television properties of Tribune Co. include two leading independent stations, in Chicago and New York. The firm owns other TV andradio stations in Colorado, Minnesota and Connecticut.

The company's revenues exceeded $800 million in 1976, on which it earned profits of $42 million. A single company is permitted to own seven TV stations - five VHFs and two UHFs. If Tribune Co. buys WDCA, it will become its fifth TV property.