What is it called when a radar's radio waves disappear or are absorbed?

Question

I don't know if I am asking this question correctly... So let me try to explain...

You are looking at a screen with a radar sweep. Usually, everything is lightened up as the sweep goes around (or the signal is going out). When something comes into the radar's view, it bleeps and lights up brighter showing that the signal gone out is being reflected/refracted/scattered/etc.

Now, what is is called when the the sweep goes around, but a portion of the signal coming off the antenna disappears into nothingness as if it has been absorbed... the signal lost and gone? (think like absorbed as in a black hole)

It would almost look like a dark spot on the radar screen... What is that "empty" area called...

I want to say it is called a "dead" something... like "dead air" or "dead space" or a "dead spot" in the radar... or "black area" or something...

Do any of you know what I mean? If so, do you know the correct technical terms?

Thanks...
T.

Answer 1

Ok Now get ready for a little reverse brain power! Something the size of an anything at all sitting anyhere or flying anywhere if it absorbed the radar signal and did not reflect it would not show anything at all because radar screen can only show what it gets in return!

Now if the object was close enough to the antenna what it would create that would be obvious would be a triangular empty shaped "shadow" a wedge shaped triangle of blank area pointing toward the area of the target that would give it away. But it would have to be very large.

See I worked in Shipbuilding protecting U.S. NavyShips with materials that absorbed radar and made them invisible just like some aircraft!

So if a Ship can dissapear 600 feet long I suppose just about any thing can!

But there is never a HOLE in a radar screen a target even if it is cloked leaves a SHADOW! There will BE ABSOLUTELY NO DETAILS OF ANY KIND IN BACK OF IT AND THE AREA WILL GROW LARGER BASED UPON THE ANGLE OF THE SWEEP OF THE ANTENNA AND THE WIDTH AND HEIGHT OF THE TARGET BLOCKING THE RADAR SIGNAL THERE WILL BE NO RETURN FROM THIS VOID AREA BECAUSE THE SIGNAL WAS ABSORBED BY THE TARGET, IT WILL BE A TRIANGULAR VOID AREA ON THE SCOPE POINTING TOWARD THE MIDDLE OF THE SCREEN.

APS

Answer 2

The sweeping line you see on a radar screen is created in the radar and has nothing to do with the signal goung out. The only time you see anything but the sweeping line is when there is an echo coming back. With no echo, you would just see the sweeping line.

Answer 3

Happy Birthday, Radio Waves! :D

Answer 4

Attentuation