Echomaster User’s Manual 00155.010, Rev. G January 2009 Total pages 16 Trim to 5.5 x 8.5" Black ink only Features, Installation, Design Principles R155E $1.
Contents Why Use a Radar Reflector? . . . . . Echomaster™ Radar Reflectors . . . How a Ship’s Radar Sees Your Boat Echomaster Specifications . . . . . . ... ... .. ... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2 .3 .4 .4 Radar Reflector Design . . . . . . . . . . . . . . . . . . . . . . . . . 6 Reflectivity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Radar Frequency . . . . . . . . . . . . . . . . . . . . . . .
foghorns, propellers, or the mighty bowwave from an onrushing “skyscraper of steel.” Even if you did spot them or detect them on your radar, which way would you turn? Best to let them “see” you instead. Furtherrnore, in distress situations the Coast Guard can be materially aided in search and rescue by the deployment of a good radar reflector. The U.S. Coast Guard is considering marine radar reflector requirements that would apply to pleasure boats operating in waters of the United States.
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.
Captive corner latches are tough, injection molded plastic to assure minimum angle error. Corner latches allow reflector to be quickly and easily assembled and demounted. Reflector stows flat. Weight without mounting hardware: 1.65 lbs. (.75 kg). #153 mounting harness weighs 1.5 oz. (.4 kg). #152 Standard Echomaster #153 Deluxe Hanging Echomaster Aluminum plates. May be assembled Anodized aluminum plates.
RADAR REFLECTOR DESIGN A professional radar reflector produces a much stronger return of the radar signal than might be expected from its modest dimensions. The conventional radar reflector consists Figure 1 Figure 2 of three mutually perpendicular metal plates which, viewed together, form a pocket (Fig. 1). If one of these pockets were to be placed on a flat surface (Fig.
Figure 4 Reflectivity. A flat metal plate placed at a right angle to a radar beam will always reflect the maximum amount of energy. Curved surfaces will reflect much less, and the effectiveness deteriorates as the curve becomes more acute. A flat metal surface perpendicular to the radar signal gives a high amount of reflected return. A slanted surface will reflect much less due to reflection of most of the signal in a direction other than the radar signal source.
On a curved surface, such as a metal mast, only a very small area will reflect the signal back; the rest is lost at numerous acute angles. Reflections from a corner reflector with circular plates, such as Echomaster, are almost as effective as a plain, flat metal surface. Radar frequency. The frequency of the radar in use has a marked effect on the amount of signal that is returned from a given sized reflector. Higher frequency or shorter wavelength radars produce much brighter returns.
Plate Design. Radar reflector plates can be triangular, circular, or square. The table below shows relative performance: Note that a reflector with a circular plate, such as Echomaster, has four times the effective radar cross-section as the triangular reflector, the most commonly seen type.
ECHOMASTER INSTALLATION Positioning the Reflector Cabins, deckhouses, sails, stacks, etc. have a “shadow effect,” blocking a radar signal. To minimize this, the reflector should be fitted as high as possible. Height also helps eliminate the effect of heavy sea and swell conditions which might otherwise blend the observed signal into sea clutter on the radar display. Avoiding shadowing by the sails is important.
Echomaster is designed to mount in the “catch rain” position by being suspended by the halyard / harness system. Alternatively, Echomaster may be permanently affixed to a mast structure. Suspended by halyard or harness. The orientation shown is the perfect “catch rain” position. Rigid mounting on a mast structure using pipe fittings. The #157 Surface Mount System could also be used, which would allow the “catch rain” position.
Slide the remaining half plate in place, as shown (reverse this half plate if the corner latches do not match). Snap in place the three remaining corner latches that secure the half plates. Mounting Echomaster #152 The standard Echomaster #152 does not include a mounting system. The best way to install this product is to assemble it around a backstay or make your own bridle and hang from holes drilled in the corner latches.
Mounting Echomaster #153 Step 1. Place the assembled reflector in the “catch rain” position with the three stamped arrows in the “up” position. Assemble one flat washer and one mounting block onto a harness wire as shown below. Push the wire up through the center-hole of the radar reflector. Step 2. Assemble the other mounting block and washer onto the closed end of the wire protruding through the top of the reflector. Step 3.
Step 4. Clip the cotter rings onto the closed end of the wires. Secure the six corner latches on the reflector with the six 1/4" (6.4 mm) nylon nuts and bolts supplied. Suspending the Echomaster from a Spreader Two small sheaves can be installed about 8" (20 cm) apart on the spreader, as shown here: Then, using a 3/16" (5 mm) braided dacron line as a halyard and the harness of the Echomaster attached, the reflector can be hoisted to within 10" (25 cm) of the spreader.
Using the #157 Surface Mount System The Davis #157 allows permanent installation of an Echomaster reflector on a hard surface or a railing up to 1.25" (32 mm) in diameter. Fasteners are not included. 1 1/2" U-bolts required for rail fastening. Note: The #157 system cannot be used on the discontinued Echomaster model #153. 1 2 3 Install mounting base to flat surface or railing. Affix tube to base. Install first corner block. 4 5 Slide on assembled reflector. Install second corner block.
Echomaster Maintenance Replacement Parts If any reflector plates should become Echomaster replacement parts may be bent, flatten them as well as possible in obtained from your dealer or Davis order to obtain the high reflective per- Instruments. formance for which the Echomaster Echomaster 152, Standard has been designed. The plates should be washed free of #R152F Corner Latches and Rivets (3 each) salt water occasionally.
