single beam fishfinder

[Pan84]

Hello
I bought humminbird matrix 12 fish finder with the single beam sonar
And i have question now, the dual beam help better to find fish? What different between single and dual beams? Dual beam sonar work deeply or widely?
Thanks

 

[solar7647]

Re: single beam fishfinder

The double will cover a wider area..so yes is does make it easyer when finding fish. It should say on the package what the degree of coverage is witch is measured by the angle from the keel line.

A single beam covers 20* a double covers 60*..you can even get side scan that will cover 86* from center on both sides...

 

[BeaufortTJustice]

Re: single beam fishfinder

Best I can tell, and I may be wrong, but a dual beam sonar allows the user to select between two different beam "widths" which allows for better performance in deep vs. shallow water. E.g. wide beam for shallow water and narrow beam for deeper water. If you use a narrow beam in shallow water, you may only be scanning a circle only a few feet wide, so by widening the beam, the sonar will scan a wider area. That is my understanding of how dual beam systems work and the purpose behind them.

 

[Huron Angler]

Re: single beam fishfinder

Well put Beaufort, couldn't explain it better than that

Basically you want a dual beam, they cost more but do much more for you than a single. A single beam with a narrow cone will pretty much only show depth and fish that are directly under the boat, in a pretty small circumference if you are in <10ft of water.

In 30+ ft of water a small cone gets big by the time it hits the bottom and bounces back.

Good luck finding the fish

 

[nam6869usmc]

Re: single beam fishfinder

My Son bought me a HB 385ci Combo that has dual beam..
DualBeam PLUS? Sonar
Your 300 Series? Fishing System uses a 200/83 kHz
DualBeam PLUS? sonar system with a wide (60?) area of
coverage. DualBeam PLUS? sonar has a narrowly
focused 20? center beam, surrounded by a second beam
of 60?, expanding your coverage to an area equal to your
depth. In 20 feet of water, the wider beam covers an area
20 feet wide. The 20? center beam is focused on the
bottom, to show you structure, weeds and cover. The
60? wide beam is hunting for fish in the wide coverage
area. DualBeam PLUS? sonar returns can be blended
together, viewed separately or compared side-by-side.
DualBeam PLUS? is ideal for a wide range of conditions -
from shallow to very deep water in both fresh and salt
water. Depth capability is affected by such factors as boat
speed, wave action, bottom hardness, water conditions
and transducer installation.
How

 

[dingbat]

Re: single beam fishfinder

Well put Beaufort, couldn't explain it better than that

Well....yes and no. It goes well beyond how big of an area you see. The different frequencies have a dramatic effect on object defintion.

A higher-frequency transducer will put out quicker, shorter, and more frequent sound waves. Like the ripples made when a small pebble is thrown into still water, small waves of sound move evenly out and away from the source. Because they are just small waves, they will not travel far, and small obstacles will cause them to bounce back. Higher frequencies are more sensitive to small objects and will send back detailed information which will show as crisp high-resolution pictures on the screen. The range of high-frequency sound waves, however, is short. Sound waves emitted by a 200 kHz transducer have a limited range of about 600?.

Now, think of the large waves created by a large boulder thrown into still water. Low-frequency sound waves are like these large waves; they travel much farther than high-frequency waves. But because low-frequency waves are so large, they wash right over small obstacles. Low-frequency sound waves are not as sensitive in detecting small fish or other small obstacles as are high-frequency waves, and although they can see to greater depths, they will not send back detailed information or clear crisp pictures.

A group of 3 fish wil most likely show up as 3 distinct marks when using 200kHz. When using the 83 kHz setting, the same 3 fish may just show up as a blob or a single return. Same for objects on the bottom. A rock on the bottom will most likely show up clearly at 200 kHz where as at 83 kHz it might just show up as a bump if anything at all.

Bottom line, 200kHz = Small view of field, great detail and resolution. 83kHz = Larger field of view, less detail, less resolution.

FWIW: Airmar makes a 200kHz transducer with a 38 x 12 degree beam which you can rotate to match the situation. Beats the heck out of using 83kHz just to get the field of view you think you need.

 

[John_S]

Re: single beam fishfinder

As nam6869usmc pointed out, HB's that are dual-beam capable, can use both together. The Matrix 12 is a single beam only. Plugging a dual beam transducer into it will not provide dual-beam capability. If you are looking for suspended fish, the wider cone of the 83kHz, will be benefitial. If you are primarily looking for fish that hold tight to the bottom, much less so.