irst, there was merger mania. Now it's joint venture vertigo.

Particularly in the risky communications business, where broadcasters, cable owners, program producers and even oil companies have been scrambling for pieces of the expanding home video market, joint ventures continue to spring up as quick as you can say CBS-Fox, or ABC-Cox.

The list goes on and on. American Broadcasting Companies Inc. is aligned with Getty Oil Co., owners of a sports network, on a new pay television sports venture; with Westinghouse's Group W on all-news cable television; with Cox Cable Communications on developing new services for cable, and with Hearst Corp. in a daytime cable network oriented to women. Meanwhile, Westinghouse is also aligned with Walt Disney Productions in launching a pay cable service.

CBS and Twentieth Century Fox announced plans in February for a joint venture, and after sticky, prolonged battles over the terms and continued deadline extensions, the two appear close to announcing the final form of that deal. It is, in essence, designed to put the two giants somewhere in the pay television wars.

RCA, already aligned with Rockefeller Center Inc. on a pay television system, and Columbia Pictures, has been stymied, in large part by high interest rates, in its plans to spin off some non-communications subsidiaries. It is willing to talk about joint ventures with almost anyone who walks through the door. "Stuff is coming over the transom," said RCA Chairman Thornton Bradshaw.

Critics say these marriages are anything but heavenly, and are designed instead to subvert the antitrust laws and in some cases block markets that might be available to smaller competitors.

"All these ventures provide ways to get around the merger laws," said Terry McGuirk, a vice president at Turner Broadcasting System, which runs Atlanta's WTBS and two Cable News Network cable services. "ABC and Westinghouse couldn't merge because of their licenses. That's why the joint venture has become the going thing."

It is certainly the case that ABC and Westinghouse could not merge, even in this era of deregulation and eased antitrust policies, unless one or both were willing to sell licensed broadcast properties. And the Reagan administration has kept its hands off these joint ventures, though it is looking carefully at several of them.

But on the other hand, joint ventures clearly lessen risks and allow businesses to dabble and experiment in ways that bring together corporate assets that might not otherwise mate.

"If you get two people together with different attributes and skills, sure it makes a lot of sense," noted John Reidy, communications analyst with Drexel Burnham Lambert. "ABC and Hearst is a good example. It's obviously a natural relationship. Both companies are natural at developing product and it does make a lot of sense."

Sometimes, however, they seem to make less sense. Reidy and others are raising questions about what each gets out of the CBS-Fox deal, for example, a marriage that has had a stormy honeymoon and has bogged down in complex negotiations which revolve largely around evaluating the assets each side wants to toss into the new enterprise.

In its earlier incarnations, the deal was to have included, for instance, CBS Cable, the critically acclaimed but money losing programming service that was to help the network take its first full-fledged cable plunge. Some industry estimates have CBS Cable losses as high as $50 million a year.

"Fox is obviously not willing to pick up the development costs of CBS Cable," Reidy asserted, although industry sources maintain the cable venture is still on the CBS/Fox negotiating block.

Designed to bring Fox's videocassette manufacturing business and massive film library together with CBS' studio facilities, cable network, and video enterprises group, the CBS-Fox deal has been touted by trade publications like Variety as a "media giant." CBS, for its part, has been a bit less bold.

Analysts and industry sources say the deal comes down to real estate and studios, with Fox yearning for access to CBS' substantial studio facilities in Hollywood. Fox, controlled by oil magnate Marvin Davis, is eager to turn its 63-acre Los Angeles studio site into a more lucrative real estate venture. "The property is too valuable to be used as a film studio," a Fox spokesman said.

Just as confusing to some industry analysts is the ABC-Getty venture, which involves Getty's Entertainment and Sports Programming Network, a 24-hour sports cable service, and ABC's efforts to merge pay television with its network sports operation. Quite simply, other than championship prize fights, ABC and ESPN can't figure out what people would pay to see on a one-shot basis.

All the uncertainty surrounding both ventures might be read, then, as an affirmation of why a joint venture might make more sense than a merger. If they fail, which most experts say is unlikely, the only bill to pay will come from the lawyers.