Another gay rights battle opened yesterday in the Miami area with petitioners, led by a homosexual rights advocate, forcing onto the Nov. 7 ballot a broad new equal opportunity ordinance that would ban discrimination based on a wide range of factors including "sexual or affectional preferences."

In including those four words, the proposal is similar to a measure repealed in a bitter and well-publicized referendum in 1977. The new proposal also seeks to forbid other discrimination - for example, against pregnant women, union members and people whose native language is not English.

For a number of years, the Dade County Code has banned discrimination in housing, employment and public accomodations on the basis of race, color, religion, ancestry, national origin, age, sex, physical handicap, marital status or place of birth.

In 1977, the commissioners added the category of affectional or sexual preference to that law, stirring a storm. Singer Anita Bryant gained nationwide attention when she helped lead a campaign to repeal it, and the campiagn won with a popular vote of more than 2 to 1.

This time, homosexual-rights activists succeeded in getting 10,000 signatures on petitions for the broader amendment, which also would expand the range of activities in which discrimination is forbidden.

A simple majority of votes cast Nov. 7 would put the proposed ordinance into effect.