In article ,
Sailaway wrote:

Just curious... Don't the marine radars have blanking, an adjustable
point where the radar emits no signal - so a mast wont reflect directly
back into the mast-mounted antenna? Or have masking, where the receiver
ignores returns that are too close - like from the mast or rigging?

They have "Blanking" designed into them that keeps the receiver turned
off, while the transmitter is on, and then allows a very short time
period to allow the reciver to turn back on to receive the echo from
the targets. This doesn't make the mast disappear, it just keeps
the receiver off while the transmit pusle is reflected off the
obstructions. It also doesn't keep the obstructions from attenuating
the returned echos before they get to the receiver, either.
It isn't that the mast is creating targets for the receiver to see, it
is the mast is attenuating the transmit and receive signals.

Bruce in alaska
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