echo box[′ek‚ō ‚bäks]
A calibrated high-Q resonant cavity that stores part of the transmitted radar pulse power and gradually feeds this energy into the receiving system after completion of the pulse transmission; used to provide an artificial target signal for test and tuning purposes. Also known as phantom target.
An apparatus designed to test and calibrate a radar set. The transmitted pulse is fed into the echo box instead of the radar antenna. The echo box then produces a delayed return pulse, the intensity of which gradually falls at a certain rate. This is fed into the radar receiver input. The echo box also helps in determining the receiver's sensitivity.