A transducer's cone angle determines its coverage area. The wider the cone angle, the greater the area that's covered. There are a variety of 192 kHz transducers with either a wide (20̊) or narrow (8̊) cone angle, and also a variety of 200 kHz transducers with either a wide (20̊) or narrow (12̊) cone angle. The 50 kHz transducers come with a 35̊ cone angle. And the dual frequency transducers come with both a narrow (12̊) 200 kHz and a 50 kHz cone angles.
Generally, use a wide cone angle for fishing shallow to medium depths.
The narrow cone penetrates to deeper depths, but shows less fish
and structure due to its narrow beam.
capability of your sonar units depends on its transmitter power, receiver, sensitivity, frequency, transducer and transducer installation
. Other things that effect depth capability are: water conditions and type, (all sonars will show deeper depth readings in fresh water than salt) and bottom conditions.
Contrary to conventional wisdom, you SHOULD paint your transducer; but use water based anti-fouling paint only.
Never use ketone-based paint, since ketones can attack many plastics possibly damaging the transducer. Airmar recommends brands such as MDR, Woolsey and Petit. These water based anti-fouling
paints can be found at your local marine
supply store or contact Gem Electronics
Telephone: 800-543-6326, or 843-394-3565, Fax: 843-394-3736
Some Transducer Tips
(From Airmar): www.airmar.com
1. The primary maintenance
requirement is keeping the active face of the transducer free of any buildup that may impede its performance, according to Peter Braffit, business development manager at Airmar Technology Corp., a major manufacturer of transducers and sensors located in Milford, N.H.
Caked-on dirt, marine
plant life and barnacles
can detract from the effectiveness of the instrument by causing turbulence or trapping air at the face. These conditions can interfere with the transmission
of sound and attenuate or muffle the reception
of the return signal.
the face of the unit should be done as soon as possible after the boat is hauled to prevent the contaminants from drying and becoming more difficult to remove. Braffit suggests that marine growth or dirt be scraped off by carefully dragging a flat tool, such as a putty knife, across the transducer face. Finish cleaning
by wet-sanding with a very fine-grit sandpaper. Wet-sanding paper is available at most marine, hardware
and automotive supply stores.
3. The face of the transducer can become scratched or nicked, causing turbulence or trapping air on the surface and eventually affecting the unit’s performance. The outer “skin” of a typical transducer face is a fairly thick layer of polymer or epoxy
, which means you can remove scratches or minor damage by wet-sanding the face.
4. The face of the transducer should be protected with antifouling paint
, according to Braffit, but Airmar recommends that only water-based paint be used
. Ketoses and other solvents that may be present in other paints may be harmful to polymers and sealant
used in the manufacture of transducer units. If non-ablative antifouling paint is used, it should not be allowed to build up more than two or three layers.
5. The sealing provisions for through-hull transducers should be closely inspected every time the boat comes out of the water. Look for dried-out or missing sealant
, or cracks that may indicate that some movement has taken place. If any of these conditions are evident, the transducer should be taken out; the old sealant removed and the unit then re-bedded into the hull. This can be a challenging task, one that may be best left to a professional who has the proper materials and expertise to handle it.
7. The wiring
of your system should be part of your regular inspection
, too. Electrical
connections must be secure and free of corrosion
. The condition of the transducer cable also is important. Braffit warns that nicks or breaks in its metallic sheathing can allow unwanted electrical noise
from other electronic devices to impact the performance of the depthsounder or fishfinder
. For the same reason, cables
radios, inverters and other potential sources of electrical interference
should not be closely bundled with transducer cables
. If the proximity is unavoidable, extra cable shielding may be required.
Contact: Airmar Technology Corp., (603) 673-9570. www.airmar.com.
Airmar to host transducer workshop at IBEX 2004
(Miami Oct 25 - 27):
Airmar Technology is to host a transducer workshop at IBEX 2004 that will help boatbuilders understand the relationship between the correct positioning of transducers and overall boat and fish-finding performance. Entitled "Transducer Placement That Assures Great Fish
Finder Performance", the one-hour workshop will be held at 1:30pm on Tuesday, October 26, at the Miami
Convention Centre in Florida
and will be hosted by two of Airmar's leading professionals - Peter Braffitt, business development manager, and engineering lab manager Steven Mills.
Airmar Transducer FAQs:
“Airmar” Transducer Catalogue c/w “Application Notes - which include electrical characteristics such as resistance”
Sensor Design Fundamentals:
Sonar tutorial from “Lowrance”: