TARGET OPERATION

The Fredwal test target is an alignment device for testing and calibrating pulse 
Doppler radars and conventional pulse radars that employ MTI (Moving Target
Information) modes of operation.  The targets are self-contained, battery-operated, 
unattended units that were designed to provide maximum radar cross-section while 
using minimum battery power.  All RF components are contained in a weatherproof 
enclosure, which is mounted immediately behind the parabolic antenna assembly.  
The radar cross-section of these targets is greater than two hundred (200) square 
meters (+24 dB square meters).

The target, when interrogated by the host radar, imparts a 180 degree phase shift 
on alternate "PRF pulses."  Three (3) foot parabolic antenna receives and re-radiates 
RF energy at the same frequency with minimum losses and with effectively zero (0) 
time delay (approximately 3 ns).

The target is passive (non-emitting) in the quiescent mode (the absence of an 
interrogating signal).  The circuitry is designed for minimum current drain to enhance 
battery life during remote unattended operation.

The phase shift of the units are aligned for one hundred eighty (180) +/- three (3) 
degrees maximum, across their respective operating bands.

These targets have been tested with 0.15 to 10.0 microsecond pulses at PRF's of 
from 0.5 to 110 kHz.

ALIGNMENT

The proper operation requires "line of sight" between the antenna of the host radar 
system and the radar target.  The target antenna is supplied in vertical, horizontal, 
or circular polarization to cooperate with the host radar.

The target antenna must be properly aligned to illuminate the antenna of the host 
radar.  A scope video monitor point is provided for this alignment purpose.