Well hallo again,
Since you appear to be interested, I will tell you the longer version of the story.
During the war there were rumors about it, but after one year have passed, people started to talk, especially after the TV show that was shown on the national TV revealing some details of this story. That's why I say that these informations are no longer classified. As a matter of fact, you can find something (including some photos) on the internet. For instance check out Venik's aviation page at http://venik.way.to. That's a Russian guy that has a lot of photos. But it can be a bit difficult to find them because his web-site is really humongous.
The Army of Yugoslavia was using different types of decoys during the war. We were heavily outnumbered and outpowered and that was our only way to survive the air-raids. We even made MiG-29s from wood in the original size with smoke boxes producing smoke from the "engines" that were planted on runaways of our military airports. It was funny listening to NATO claiming to have destroyed some 20-30 MiG-29s when I knew that we have had only 16 of them at the beginning of their attacks.:-)
Some of the decoys were the radar imitating ones. We used models of radars - usually some metal construction that looked like radar put on some old junk truck with something to emit waves so that it looks just like radar to the incoming enemy pilots - both visually and electromagneticaly (they were emitting radio-waves at short wave lengths). So we have simply let them attack, because we've had next to nothing to defend with, the catch is only that they were usually destroying decoys and empty objects. That's how we made it for 78 days.
The most common thing used for emitting radio-waves of the same wave-lengths as of the radars was an ordinary microwave oven. I supposed that you know that the energy of electro-magnetic waves is directly proportional to their frequency. The formula E=h*f where E is energy, f is frequency and h is Planck's constant. The radar needs to emit the enormous amounts of energy, because the wave needs to go very far (hundreds of kilometers) than to reflect from the object (in this case an airplane) and after all to came back all the way and still remain strong enough that you can reliably receive it and actually see the incoming plane on the radar screen. That's why the radar uses extremely short wave lengths. The shorter the wave length - the bigger the frequency. The bigger the frequency - the bigger the energy. That simple.
On the other hand the microwave oven also needs the big amounts of energy because it's primar purpose is cooking which requires a lot of energy. For the same reason as radar the microwave uses short wave lengths. These wave - lengths are widely known as MICRO-WAVES.
That's how someone came to an idea of using microwave ovens. It would have been certainly much better if we have had developed special decoys, but it was in the middle of the war, and something like that would have taken months of construction.
The existing microwave ovens were just set to work with their doors opened and used as decoys. They were emitting microwaves that were like the ones from air-defense radars.
About your question: can the real radar operate when surrounded by microwaves? Well I'm not sure. I suppose that it can. And why not? It only uses one frequency for sending and the same frequency for receiving. It is probably not disturbed by the frequencies sent by MW ovens that operate at different but close frequency. The radar can be set to work at various frequencies and I suppose that all the MW ovens doesn't use the same frequency as well. There are several devices that transceive at various (but close) frequencies in MW band, but only one of them is receiving his own frequency. That's my guess, but I don't know for sure.
What I know for sure is that we were also using some very old soviet-made radars (from the 1950's) that used extremely long waves (long for MW band, of course - everything is relative, as someone once said :-). These radars were considered hopelessly obsolete, but they came as a surprise for NATO. They just didn't expect that something working on that frequency is actually air-defense radar! So, while they were shooting poor MW ovens the real radar was working, giving coordinates to SAMs. And then... Well you can guess what was happening next. :-)
A typical MW oven has the output power of cca. 1-2kW and a big air defense radar has cca. ~100kW. I'm not sure if we were using several of them placed close to each others to increase power, or something else, but it certainly worked on smaller distances.
The most common tactics we've used is this: All those pilots weren't certainly a bunch of morons who cannot tell the difference between the radar and a decoy pretending to be one. After they suffered the first casualties they learned their lessons. So their typical tactics for attack was: First the big bombers (flying fortress' B-52) flies high above our missile range dropping tens of HARMs (Homing Anti-Radar Missile) that are falling slowly because they are hanging from special parachutes. They need 10-15 minutes to fall on the ground and in the meantime they are seeking for radars - if they spot a source of radar radiation, they automatically unhook their parachutes and activate their booster rockets heading fast toward the radar. That gives the opportunity for other airplanes to attack at lower altitudes for precise bombing without a risk of being spotted by a radar, because no radar can be turned on without being destroyed by HARM in just a few short minutes. But a HARM is just a piece of hardware that CANNOT tell the difference. That's when we turn on our numerous MW ovens. HARMS naturally rush to destroy the "radars", and in a few minutes the sky is clear of HARMS. The remaining airplanes can either attack risking to become a prey for our real radars that can be turned on now, or go back home without attacking their targets.
That's the story. Post it on your site if you've liked it. Actually, post the parts of it on your site, because I think it is too big to be posted entirely. Feel free to add my name - I would be happy to see my name there.
Thank you for your concern about my future - it is much better now then it was lust year at this time. We are slowly recovering from consequences of war. Except, of course, for the lost lives, and depleted uranium that will take centuries to disappear. But that's another story.
Best regards from Belgrade,
P.S: By the way, I have just remembered of one more similarity between MW oven and a radar. I've read a story once about some people on the military airport that have killed a rabbit in the nearby field (200-300m) by using an airplane radar. They simply pointed the radar on the poor rabbit and cooked him instantly! At first, I didn't believe the story, but when I thought about it scientifically (since I'm a student of electrical engineering here in Belgrade :-), I' ve changed my mind. Just imagine something that is about hundred times more powerful than a MW oven and has focused beam pointed into that rabbit. What do you think that would happened?