Echomaster specifications, How a ship’s radar sees your boat – DAVIS EchoMaster Radar Reflector User Manual
Page 4
Echomaster Specifications
Reflector plates are 12.5" (32 cm) diameter,
circular, aluminum. Plates provide 13.2
square yards (12 sq. meters) of maximum
effective radar cross section in the X or 3 cm
band (9–9.6 GHz frequency), based on opti-
mum orientation between the reflector and
radar. Echomaster offers equivalent radar
cross section of conventional triangular plate
reflector with approximate 17" (43 cm) diago-
nal dimension.
Plates are made of robust 0.05" (1.3 mm) marine grade aluminum; sufficient thick-
ness to minimize flexing. Dimples in plates allow corner latches to attach precisely,
minimizing angular distortion.
Windage holes reduce aerodynamic drag and allow assembly of the reflector around
a backstay. Windage hole size 1.25" (32 mm).
DAVIS
ECHOMASTER
#152, 153
DAVIS
EMERGENCY
RADAR
REFLECTOR
#151
MOBRI RADAR
REFLECTOR
FIRDELL
BLIPPER
RADAR
FLAG
Admiralty surface weapons test, England
4
How a Ship’s Radar Sees Your Boat
The radar of a ship making a complete circle around a boat would hit the boat’s
radar reflector from all angles. If the boat were stationary and we plotted how strong
the reflected signal is at all angles, we would arrive at performance diagrams such
as this…
The outside of the circle is what a 10
2
meter cross section of a metallic sphere
would reflect—the laboratory standard. The larger the performance plot, the better
the radar reflector. Peaks in the pattern should approach the laboratory standard and
be uniformly distributed 360° around the fixed reference point (your boat). Valleys
should be minimal in width. The Davis reflectors show good balance: strong peaks,
narrow valleys. Other reflectors have inadequate peaks or large areas of weak
response, making them seem smaller on an oncoming ship’s radar screen.