At the international conference to change world radio rules, the United States has avoided threatened blowups on most key issues with a time honored technique: delay.

But the delays at the World Radio Conference here have been gained at a price to U.S. interests, particularly in the high frequency broadcasting area where, ironically, the U.S. had the support of Iran and Pakistan, but not most of the remaining Third World nations.

Because of the first-time involvement of many of the Third World countries at the conference there were fears within the U.S. community that the meeting would lead to widespread changes in world communications -- changes unfavorable to the U.S.

At the start of the conference, Third World countries announced plans to try and shift the entire emphasis of the meeting toward forcing the industrialized nations with the most advanced communications technology to help the less developed nations. Those plans never materialized.

Still the U.S. did lose out on some of its hundreds of proposals here. And, to head off major changes in the world's communications system, the U.S. and other industrial nations did make some commitments to help meet the needs of developing nations.

Many U.S. proposals to expand shortwave broadcasting around the world failed, defeated largely by countries that wanted to continue to use the desired frequencies for fixed satellite domestic services, such as low-priced radio telephone systems that can reach outlying areas.

Outside of a few minor gains in this area, the U.S. has only faint hopes of future gains at another special conference scheduled within five years, to deal with broadcasting issues.

Other key U.S. setbacks came in attempts to reallocate part of the existing UHF (ultra high frequency) television band to land mobile services, such as police and private two-way radio systems. In that area, the U.S. was overruled by Canada, Cuba and Mexico, who wish to keep uhf for television, and fear interference from nearby U.S. mobile systems. The U.S. also failed in an attempt to significantly increase allotments for marine broadcasting services, such as a ship to shore radio.

U.S. Military representatives to WARC were unhappy with some decisions forcing it to share frequencies it now uses for radar.

But in those cases, the U.S. has indicated that it will take a "reservation," a protocal statement that essentially means the U.S. will continue to use radar in the specified bands anyway, and do its best to limit any interference between the most powerful radar and other forms of communications that now will be allowed on those bands.

Another U.S. Proposal to allocate a special frequency for an experimental solar power-generating satellite, also failed. The U.S. did succeed in gaining some recognition for the plan, which would involve a 20-square-mile solar collector satellite that would transmitt power back to earth. But third-world fears that such transmissions could prove to be environmentally harmful prevented the conference from going as far as to give it an allocation until it is proven safe.

In a Press briefing here today, the head of the U.S. Delegation Glen Robinson, emphasized the victories rather than the defeats.

"We're quite well satisfied," Robinson said, "especially (when considering) the anxieties expressed in the press and by some groups before the conference. We think the conference has been a success. There has been a minimum of political debate. There has been a good working rapport between the various administrations, and the conference is ending on an unbeat note."