Perhaps no one understands the value of a shortwave radio better than the thousands of Westerners trapped in Kuwait after the oil-rich sheikdom was invaded by Iraq last August.

Westerners who have since fled Kuwait report that they depended on portable shortwave radios for much of their news, including information about possible routes of escape.Few travelers will ever face that sort of ordeal, but the Iraqi invasion points up how a shortwave radio can provide a source of news and entertainment thousands of miles from home.

For those in remote, information-starved corners of the world, it can be the only source.

Thanks to advances in electronics, shortwave sets are smaller and cheaper and sound better than ever. A set about the size of a paperback costs as little as $75.

By spinning a dial, an American on safari in Africa can keep up with the latest football scores on the Voice of America.

While trekking in the Himalayas, a Wall Street executive need never be out of touch with the financial exchanges; the business news is broadcast hourly on the shortwave service of the BBC.

"When something like this Persian Gulf situation happens, the interest in shortwave really grows," said Gene Kelsey, a product manager for Panasonic, one of the largest manufacturers of shortwave radios.

He estimated that sales of Panasonic shortwave equipment would increase 4 or 5 percent this year.

The radio frequencies used for regular AM and FM radio cannot reach listeners beyond a few hundred miles.

Shortwave signals - the waves are indeed shorter than those used in regular commercial radio - rise high into the sky and then bounce off the ionosphere, returning to earth thousands of miles from their source, making it possible to beam shortwave broadcasts across continents.

Virtually all programming is government sponsored, and more than 140 countries offer programs.

For English-speaking travelers, the most important services are the Voice of America, the BBC, Radio Canada, Radio Australia and the English-language service of Deutsche Welle, the German radio network.

The Voice of America broadcasts in more than 35 languages as well as English and estimates its worldwide audience at 130 million. Its news reporters are stationed in more than 20 cities, including Moscow and Beijing.

The BBC World Service is generally thought to set the standard for shortwave programming, with news broadcasts, radio dramas, concerts and quiz shows.

Because of powerful transmitters, the English-language service of Radio Moscow, the official Soviet shortwave service, can be heard in most parts of the world, often better than the Voice of America or the BBC.

For most of its history, the programming on Radio Moscow was pure propaganda, but listeners now say that with glasnost in the Soviet Union some freedom has come to Radio Moscow.

Until several years ago, shortwave radios were bulky devices that weighed 15 pounds or more.

But with the advent of semiconductor technology, shortwave manufacturers have been building battery-powered shortwave sets that can be tucked into a backpack, a briefcase or a shirt pocket.

"It was back in '84 and '85 that we moved away from tabletop models and focused on portables," said Kelsey of Panasonic.

One of Sony's most popular models - the SW20, suggested retail price: $99.95 - weighs 9.6 ounces, fits in the palm of a hand and produces sound as clear as many larger, more expensive models of a few years ago.

Shortwave enthusiasts offer first-time buyers two pieces of advice: keep it simple and resist an impulse to spend a lot of money. "I recommend that they get a small portable model, travel with it and get a feeling for how it works," MacKenzie said.

Because shortwave transmission is never as clear as a regular radio broadcast - in part because the signals are so susceptible to atmospheric conditions - the difference in sound between a moderately priced set and a top-of-the-line model can be negligible.

Virtually all sets are multiband, meaning they include standard AM and FM stations. Among the features offered by more expensive models are digital readouts, buttons that allow a listener to preset stations and automatic scanners that search the dial for the clearest signal.

Some shortwave sets come with an alarm clock, allowing a listener to wake up to the news or a favorite music show. Others have tuning controls that resemble the keypad on a touch-tone telephone.

While virtually all sets come with a built-in antenna, it is possible to buy a more powerful, portable antenna, but there is a less expensive alternative.

"All you have to do is get a big piece of wire," said William E. Oliver of the National American Shortwave Association. "I just string wire around the four corners of a room and plug into the back of my set."

Shortwave prices range from about $50 for a compact portable to $2,000 or more for one of the large tabletop sets. Shopping around is advisable since prices are heavily discounted.

Panasonic, for example, lists retail prices for its shortwave sets from $90 to $280, but discounters in New York will sell you the same products for a third off or more.

Locating desired programs on the shortwave dial can frustrate new enthusiasts. They find it difficult and time consuming to spin the dial. A simple shortcut is to consult a shortwave guidebook. One is often included in the price of the set.

Sony, for example, periodically issues its Wave Handbook, which lists shortwave services by country, the frequencies, the hours and the languages.

An American traveling in Warsaw and wishing to hear an English-language broadcast by the BBC in the afternoon is advised to try 15070 kilohertz. A Polish visitor in New York wanting to listen to news from back home in the late evening on Radio Polonia is advised to tune to 11815 kilohertz.

For a traveler who has little suitcase space, Panasonic offers the RF-B10 (suggested retail price $90), which at 23/8 by 4-and-5/16 inches can fit into a shirt pocket. It weighs less than half a pound. Sony has a similar compact model, the SW20, at $99.

At the upper end of the price range is Sony's 2010 ($429.95), which has long been popular among diplomats and foreign correspondents. Among its features are 32 memory presets and a clock.

Shortwave enthusiasts often recommend the Grundig Satellit 500 ($649), which has a liquid-crystal display panel and separate bass and treble controls. Each of its 42 memory presets can be labeled with four letters or numbers - a listener might program one station as BBC, another as VOA.

Shortwave sets do not pose any special problem at airport-security stations. But like other electronic equipment, they may be inspected closely.

International travelers are often asked to remove a radio from their hand luggage and turn it on.

Travelers in India and the Middle East report that, before boarding domestic flights, they have been forced to remove the batteries from shortwave sets and other radios.