As the television camera focused on the curving, whitewashed facade of the U.S. Air Force hospital here, where the 52 hostages may be brought if released by Iran, CBS television correspondent Bob McNamara stood shivering in the cold trying to decide what to say when he went on the air.

"You can report all the conjecture and wild rumors you want, but there are very, very few hard facts," he complained, reflecting the problem faced by hundreds of journalists from all over the world who have descended on this small, snow-covered Rhine River city.

To begin with, they had no idea whether the event they were sent to cover would occur. They pored over teletype news from Washington, Tehran and Algiers and listened to round-the-clock broadcasts on Armed Forces Network radio for the latest on the U.S.-Iranian negotiations.

Air Force officers at the hospital here, and at the U.S. Rhein-Main Air Base adjacent to the Frankfurt Airport about 20 miles from Wiesbden, offered the barest background details and tight restrictions on how the media would be allowed to witness the hostages' arrival. "And that's if they even come here," one senior military public information officer kept repeating, "and that's off the record, too."

"You might not believe this, but I really don't know any more than you do," explained another officer, Maj. Bruce Fagaley.

Fagaley escorted reporters around the Rhein-Main base and on to the tarmac where the hostages might land in specially outfitted Air Force C9 Nightingale medical-evacuation planes, which were still parked near the gates of the base.

Reporters would be able to watch the hostages emerge from the hospital planes to waiting ambulance buses from a restricted area in front of a small, World War II-vintage control tower that looks across the vast runway to the concrete, glass and steel of the ultramodern Frankfurt Airport. r

According to the generally accepted scenario, two of the C9s would fly the hostages here from a transfer point -- most likely Algiers, Stockholm, Geneva or Zurich -- where they would have been taken from Iran in a neutral country's aircraft.

After perhaps a brief welcome on their arrival at Rhein-Main Air Base from a U.S. delegation including former secretary of state Cyrun Vance -- "A television reporter told me about Vance, and I can't confirm that," said an Air Force officer of that development announced in Washington -- the 52 Americans would be driven to the hospital for several days of examinations, debriefing and "catching their breath" before going to the United States.

The hospital here, built by the Germans during World War II and taken over by the U.s. military along with other installations around Wiesbaden, has 235 beds and more than 800 medical, nursing and custodial staff in 20 white concrete buildings. Officials said it has been ready to receive the hostages since shortly after they were seized Nov. 4, 1979.

Each hostage is expected to have a room equipped with a TV set tied into the Armed Forces Network of programs from the United States, and a free telephone. They would be given thorough physical and psychiatric examinations and counseling, and would attend a press conference only if they chose to.

Although the State Department believes it would be best if relatives of the hostages waited in the United States, according to officials, there would be accommodations for them in the Air Force's Amelia Earhart Hotel next to the hospital. They also would meet the press only if they wanted to.

The television crews and reporters thus may get only the briefest glimpses of the hostages as they are moved from place to place. Nevertheless approximately 700 are here.

They have filled hotels in Wiesbaden and at Frankfurt Airport, where a camera with a long lens could catch the hostages' arrival at the air base opposite. New arrivals have added still more equipment to the tons already stockpiled in and around the airport since October -- when what may be the longest and most expensive media stakeout began in earnest during the flurry of negotiations just before the presidential election.

Because of limited satellite capacity for transmission, the networks intend to pool their live coverage of the hotages' movements.

To the uninitiated, the expense of the electronic stakeout, appears staggering. Lond-based network officials supervising the operation here will not discuss the cost, but they are known to be pleased about the opportunity to take possession of some of the expensive equipment specially shipped over from the United States. Technicians have passed part of the waiting time busily changing the labels.