Different angle transducers

[Herb L]

Is there a chart or a way to figure how much area a transducer is covering at ,say 20',. How much does a 20 degree or a 10 degree cover. I remember reading this somewhere but now that I need it I can't think of it to save my ----.. Thanks Herb L

 

[hankll]

Re: Different angle transducers

On my BottomLine which is a 200 Khz/19 degree beam, the handbook says you can calculate the diameter of the main beam on the bottom as Depth divided by three, but you will also have weaker beams that would be surrounding the main beam so it can, depending on your gain, "see" a wider coverage. So for a 30 foot depth, you'd have an approximate diameter of 10 foot coverage not including the weaker beams. Not sure of other manufacturers, but its probably similar for their units.

 

[rolmops]

Re: Different angle transducers

I use a quadra beam humminbird 575 and under different angles it uses a different wavelength just so the reading does not get "strange".When using a 90 degree every foot of depth makes for 2 feet of bottom,60 degree is a bit better than one on one and the 20 is as mentioned above.
This type of fish finder is only good for deep (100 foot +) water trolling.
You can go to the Humminbird website or pick up one of their sales catalogues and you will find the exact answer to your question inside.

 

[jtexas]

Re: Different angle transducers

The coverage area is a circle centered directly under the transducer, with a radius equal to the depth divided by the tangent of half the cone angle.

So with a 20? angle 'ducer at thirty feet, you get 30 x .176327 = 5.2898 ft from the transducer in all directions.

But it actually varies with the sensitivity setting. Echos from outside the cone are faint but can be detected with the gain turned up.

So it's not exactly linear, but general rule of thumb, 20? 'ducer diameter = about 1/3 the depth, 10? ducer diameter = about 1/5 the depth.

 

[Herb L]

Re: Different angle transducers

O.K. Thanks a lot everyone for your input. I knew that there was a way to get a general figure but had just forgotten how, but the rule of thumb of 1/3 and 1/5 was it