BA­SIC ELEC­TRON­ICS 5

For some, in­ter­pret­ing a fish finder’s screen can be very chal­leng­ing. Here is ad­vice on how to make sense of what you see.

SA Bass - - Front Page -

Sonar mea­sures dis­tance us­ing time. The best way to de­scribe it is; the fish finder’s screen is just turn­ing lights on and off, depend­ing on how far the ob­ject is from the trans­ducer and the time it was in con­tact with the trans­ducer to mea­sure that dis­tance.

Those im­agesg can be the bot­tom, struc­ture, an ob­ject close to the bot­tom and now and then it will be some­thing swim­ming or drift­ing in the wa­ter col­umn.

Arches

If you are not an ex­pe­ri­enced fish finder reader it can beb slightly dif­fi­cult to read the dis­played images. To see theth typ­i­cal fish arches the boat has to move slowly over theth fish. Why the fish ap­pears like arches on the screen is th the most asked ques­tion. It’s all about the in­ter­ac­tion time be be­tween the trans­ducer and the fish. As soon as the fish comesco in con­tact with the outer edge of the trans­ducer’s sig­nal­sig the screen will be ac­ti­vated. At the same time as the fish moves nearer to the cen­tre line, the dis­tance be­tween the trans­ducer and the fish de­creases.

Th The de­crease in the dis­tance will cause the line to curve. As t the fish ar­rive di­rectly at the cen­tre­line of the cone the first fi­fi­first half of the fish arch is done. When the fish move away from the cen­tre line the pix­els will com­plete the sec­ond halfhal of the arch.

Some­thing to re­mem­ber: if the boat is not mov­ing the fi­fi­fi­fi­fi­fi­fish fish will show as a hor­i­zon­tal line. When fish are mov­ing thro through the cen­tre line of the trans­ducer’s cone, the arch will not be as dis­tinct.

Th The length of the arch has not any­thing to do with size of the fish. Long arches is only show­ing the time it took to move to­wards,t or over the ob­ject it has picked up, based upon y your hor­i­zon­tal speed. If you un­der­stand this you will be fine.

To sees the sizes of the fish you have to look at the top (cen­tre) of the arch. Big fish will ap­pear with a wide cen­tre and vice versa, (smaller fish - nar­row cen­tre). Gen­er­ally we think all arches are fish. Yes it can be, but it can prob­a­bly

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