What Ukraine's Kolchuga radar does

The controversy surrounding the Kolchuga radar is worthy of a Cold War spy novel.

Wrongly dubbed by some as a radar that can spot stealth aircraft, the alleged provision of the system to Iraq is inevitably provoking some tensions between Ukraine and the United States.

The Kolchuga radar is manufactured by a Donetsk-based company called Topaz and is marketed by a state-owned organisation called UkrspetsExport.

Its director general, Valery Malev, was killed in a road accident in March of this year, just before a parliamentary commission announced that it had evidence suggesting illicit Ukrainian weapons sales to Iraq.

Amidst all the murky conspiracy theories, it is very hard to get firm details about the capabilities of the system.

However, unlike normal radars which send out waves that bounce back from the target, Kolchuga is a passive system.

In other words, it detects emissions coming from the target aircraft.

This would make it far less capable against stealth or radar-evading technology because by definition these planes have little or no active emissions.

If the Kolchuga system is being used by Iraq, it poses far more of a threat to conventional non-stealthy aircraft - the types of British and US warplanes that are patrolling the no-fly zones over Iraq every day.

President Saddam Hussein has made no secret of his desire to shoot down one of these aircraft.

And given the frequency of the flights, US and British pilots have depended upon skill and a good deal of luck so far to avoid any losses.

Kolchuga would be far less significant in any large-scale US assault against Iraq where the country's air defence system as a whole would be an early target.

The row over Kolchuga is symptomatic of the wider problems between Ukraine and the West.

Nato sources have told the BBC that there is growing concern within the alliance's headquarters in Brussels about the direction being taken by President Leonid Kuchma.

The arrival of the US and British team to discuss the radar issue represents something of a sticking plaster being applied over what could become a gaping wound in relations.