Americans in Egypt: will familiarity breed contempt?; With huge US diplomatic community in Cairo, officials are making a special effort not to step on Egyptian toes

He remembers standing at the train station far up the Nile on a lonely night not long ago, trying to make one of Egypt's infernal telephones work. A big, self-assured man, there was little mistaking his Americanness.

Hearing his accent, a group of college students struck up a conversation. What did Americans think of Ayatollah Khomeini? The American (name withheld) responded negatively. But Khomeini was wonderful, they retorted. Islam would sweep the world in 10 years.

The American could barely contain himself. Fortunately for him and for the United States, he did. The encounter ended with simple good-nights and a lesson learned in patience.

Every day, up and down the Nile - in brown-dirt, backwater towns and sleek, new Cairo high-rise buildings; out in the parched highlands of the eastern desert, at Red Sea oil projects, and in the Suez Canal zone - Americans and Egyptians are learning to live with each other.

Sometimes there are problems. So far, there have been no major incidents.

Journalistic eyebrows rise at the news that the American Embassy in Cairo is one of the largest in the world; before Egypt, it is ominously reported, Saigon and Tehran were biggest.

The arrival of two American radar planes Oct. 15, an expansion of US-Egyptian military exercises here next month, and the offer of Egyptian territory to be used by the American Rapid Deployment Force in the event of a Middle East crisis all point, for better or worse, to a mushrooming American commitment to Egypt.

Will familiarity breed contempt?

No one knows, of course, but a variety of Americans and Egyptians here, civilians as well as government officials, say Americans are making a special effort not to step on toes.

''It's not like it was with the Soviets (who were in Egypt from the mid-'50s to the mid-'70s),'' says an Egyptian journalist.

''There is much respect for the US. I do hear leftists and intellectuals criticize US policy. Sometimes some people will make fun of the tourists, but it hardly ever goes past that. Americans are easier to understand than Russians. I think most Egyptians agreed with Sadat's argument that there is only one real superpower in the world. Sadat believed in the superiority of American technology. I think most Egyptians do, too.''

But there are anti-American Egyptians as well, led by the militants of the Muslim Brotherhood and its offshoots.

''The message of the Muslim Brotherhood,' writes Saad Eddin Ibrahim of the American University of Cairo, ''is unequivocal denunciation of President Sadat's current policy of drumming up support for an alliance with the US to ward off the 'Soviet threat'. . . . The Muslim Brotherhood perceives Egypt as having a divine mission in forming and leading an alliance of all Muslims against the three archenemies of the faith - the West, the Soviets, and the Israelis.''

But Western diplomats say they recall no clearly anti-American incidents in Egypt in at least the past two years and probably longer. The last major incident, in fact, was the 1967 burning of the American cultural center, but even then person-to-person dealings are recalled as ''very friendly.''

''I've never experienced impoliteness, not to say hostility,'' says a diplomat twice posted here.

The size of the American presence here is what is worrying many observers. But the 10,000 Americans in Egypt are a smaller group than the 25,000 estimated to be stationed in Saudi Arabia's Eastern Province alone. In Iran during the late '70s there were 40,000 Americans.

Naturally, modest community size and peace so far do not guarantee the future. And the snowballing American commitment to this country could, indeed, cause a reaction, Egyptian observers say.

But, as is true of most cases of heavy US involvement, there are logical explanations for the size of the embassy, of the American community, and of the military presence, officials argue.

The US Embassy's size (600 permanent and nonpermanent staffers) is primarily due to US AID (Aid for Industrial Development), which administers $1.2 billion per year in economic assistance. Add to the 150-person AID staff those affiliated with technically nonpolitical posts (the Library of Congress, Fulbright Commission, Navy Medical Research), and the embassy is smaller than many US posts in Europe, officials say.

The large military presence - seen primarily in the 250-man Bureau of Military Cooperation in the embassy - is an outgrowth of the Camp David treaty, of which the US is a partner. It has expanded because of the Egyptian desire to arm and train with American weapons (an operation only 40 percent complete), and because of Washington's view of the strategic importance of Egypt.

Whether the American commitment is overly large is a question that perhaps only policymakers in Washington can answer. Egyptian officials are making no objections.

Egypt's Hosni Mubarak, like Anwar Sadat, says Egypt belongs squarely in the Western camp - though Mubarak is much more soft-spoken about this than was Sadat. He is said to understand the need to play down the American military presence so as not to antagonize nonaligned and pro-Soviet neighbors, as well as opponents in his own country.

Washington's gesture of sending American AWACS to Egypt has been welcomed by Mubarak, but aides say he is confident enough of Egypt's ability to defend itself. Egyptian strategists indicate that where coordination with America is most helpful is in the Red Sea region.

American interests coincide with Egyptian in this area. US economic and military aid is being increased to Sudan; the US is expanding the Somali port of Berbera for Rapid Deployment Force and naval use; the US, Egypt, and Saudi Arabia are aiding North Yemen and Oman in an attempt to check Marxist South Yemen.

For the time being at least, most observers here do not expect a clash of views between Cairo and Washington. Nor, due to the heavy emphasis on law and order by President Mubarak, are major anti-American reactions, even by Muslim militants, likely. A change of policy, an ugly incident involving Americans there or Westerners, and the story could be different.

''They're a proud people, used to foreigners,'' says a Western diplomat. ''As long as you don't try to dominate them, there can be a community of interest.''