In the two weeks since the unsuccessful U.S. attempt to rescue the hostages in Tehran, the families of the 53 American captives have had no letters, messages, or word from their relatives.

But worse than the days of silence, they say, is the new uncertainty about where the hostages are being held.

Several times during the last week, Iranian militants who have occupied the U.S. Embassy for the last 6-1/2 months said that the hostages had been dispersed around the country. Some of the hostages' families believe the reports, and others are skeptical. All are uncomfortable in dealing with a new unknown.

"Before the raid we knew where they were," said Pearl Golacinski of Silver Spring, mother of 29-year-old regional security officer Alan Bruce Golacinski. The familiar sight of the American Embassy compound on the nightly news provided a small measure of reassurance.

"We had a place to send our mail and we could see where they were," she said. "Now, we just don't know."

Mary Lopez, mother of Marine Sgt. James Michael Lopez, 21, said, "We were used to the idea he was there. This way, we think, 'I wonder where he's at.' It's almost like somebody being lost at war. You wonder where he is, whether he's alive, what he's doing," she said in a telephone interview from her Globe, Ariz., home.

Louisa Kennedy, spokesman for the Family Liaison Action Group, gives little credit to the reports that the hostages have been moved. "We have no proof of any kind that they've been moved, and I think we'd probably know if they had," she said yesterday.

Hostage families interviewed yesterday said the last letters they received were dated about a week before the aborted April 24 raid.

"We received a handwritten message from Donald after the Red Cross visit several weeks ago," said Ernest Cooke of Memphis, father of 25-year-old vice consul Donald J. Cooke.

Others said they had heard little from the State Department recently. "They don't seem to know much or else they won't tell us much," said Golacinski, one of four relatives who recently returned from Europe following a mission to persuade American allies to support sanctions against the Iranian government.

Dorothea Morefield, wife of 50-year-old Consul General Richard Morefield, also expressed frustration at the vagueness of the State Department officials she had spoken with. "If they don't want to tell me [where the hostages are], I can understand that," she said.

"But I would like to know that they know."

The last communication the Morefields have had from Richard was a letter to their 20-year-old son, Dan which arrived last week but which was dated April 18. In it, Morefield said he received a package of magazines (Ellery Queen Mysteries and Analog Science Fiction) and books that Dorothea Morefield had sent.

"I was so tickled that he had gotten one of the packages," she said. "But he's tired, like all of us. I can tell the difference in tone from his earlier letters."

Cooke said that the most recent letters from his son indicate his impatience at being held a prisoner, a fact Cooke interprets as a good sign. "In his Red Cross message in April he said, "It's going on six months and that's one fiftieth of my life," Cooke recalled.

'When he wrote after his 25th birthday in February, he said, 'What do you get the hostage who has everything? You get him out of here."

Despite the uncertainties about the location of the hostages, State Department officials say they are continuing to advise families to send mail directly to the American Embassy in Tehran.

Letters like those the Cookes have received, filled with humdrum facts, affection and irritation, offer what the families in this country want most right now: first-hand accounts of life for the hostages.

The two-week silences is not unusual in itself. But failure to hear from the captives, coupled with the new uncertainties about the situation, "has everyone worried," said the father of one hostage, requesting that his name not be used. "We're concerned, just as anyone is, when you're faced with the unknown," he said.

About eight of the hostages' families attended memorial services yesterday at Arlington National Cemetery for the eight servicemen killed in the collision of a helicopter and a C130 cargo plane when the rescue mission was being aborted last month.