What does "only reacts to objects with this property"

Except from this:

The Radar Sensor acts like a real radar. It looks for an object along the axis indicated with the axis buttons “X, Y, Z”. If a property name is entered into the “Prop:” field, it only reacts to objects with this property.

Does it mean that if I have a cube object and in its properties I give it a property, um, called ‘contact’.

Then in the object I want to detect collision, I put ‘contact’ in the Prop: box as above?

And what kind of property does ‘contact’ have to be defined as?

Thanks much.

Well I tried that and that didnt work either. I dont think the GE is very usful without collision detection. I know it does work using python, because it works in the hunting game.
Help please, my already thining hair is thining more. I really want to get this silly game done so I can donate it, and move on.
Heres the blend:
only the mouse on the left is in motion etc.

yes yes yes - you have the right idea.

and ‘contact’ can be any type of property.

Thanks for helping, but it doesnt work. I have it set to terminate the object, but nothing. And Im done, this is just wasting my time. So if someone wants to finsh this for the donation fine. Go for it, have a ball, as on of my computer science instructors used to say. LOL.

The radar sensor has issues, you may want to use a series of ray sensors or some sort of object to act as the detector.

HUH? _________

Well for a long time the radar sensor was solid and caused objects to fly all over the place.

You may want to have an object shaped like a radar slice and hook it up to a near or collision sensor, that would be one way to get around it.

Whoosh…right over my head. But thanks for trying to help me. I do appreciate it.