Switchfire Settings

What does everyone use for their switchfire settings to really produce good arches when driving over fish and what speed do you usually run the boat? Thanks

Chart speed=boat speed
Sensitivity set to show the amount of clutter I want.
200/83

I like to run 200/80 as well. I primarily run it in clear mode with the sensitivity turned up to see what I want.

Chart speed is alway on 10. Chart speed=boat speed is primarily for side and down imaging.

Nice level transducer will help get arches. I get decent arches up to about 10mph and then not so much due to turbulence.

JAnderson wrote:

Chart speed is alway on 10. Chart speed=boat speed is primarily for side and down imaging.

That’s entirely not true.

When you don’t match your boat speed:
Chart speed faster than boat speed = all objects are stretched
Chart speed slower than boat speed = all objects are shrunk.

Chart speed matched to boat speed = all objects true to scale.

Understanding how a sonar works, whether it be 2D, SI, or DI will greatly help you decifer what shows up on your depthfinders boys!!

It’s not just colors and arches on a screen.

The “Arch” is created by an object passing through your cone.

As an object enters your cone it is further from your transducer. As it gets closer to directly underneath your transducer the object is now closer to your transducer. As the transducer passes by the object the object becomes further away from the transducer. Note, the object never changes depth, but an “Arch” is created because the distance changes as you pass over the object. The thicker the return the larger the object. The length of the return means very little. Thickness is everything. Notice how the beginning and end of an arch is usually a lighter return in color and much thinner. This is because when the object enters and leaves the cone it is further away than when it was underneath the sonar, and the sonar intreprets that as a “Softer” return … Or further away – smaller.

That’s the arch folks. It’s like standing in a tree with a rangefinder and scanning a flat cement pad below. Your distance changes – that’s the arch.

Yeah. I understand how it works. However, I feel that changing chart speed on the traditional 2d sonar is not necessary. I am able to see the arches just fine and do not need them to be exactly true to scale. I do feel that it is much more important for di/si to increase the clarity in the picture. Without adjusting chart speed here…everything is extremely distorted. In 2d it does not seem that distorted. However, I will give it a try next time out and see if I enjoy the difference. Thanks for the heads up.

To each his own I guess…whatever people feel they need to do. I would guess that 99% of people do not adjust chart speed on 2d.

All i’m saying is that it effects SI, DI, or 2D EXACTLY THE SAME WAY.
That’s the science (Facts) behind the technology.

Your graph on high speed, all your images are distorted…YOur just used to looking at them that way.

Thanks but I still am not convinced with that. Here’s why:

A good explanation of TVG from Greg Walters @ Humminbird follows. TVG is now implemented as SwitchFire: “TVG = Time Variable Gain. Basically what it does is equalize the returned sonar signals so that a fish that is close to the transducer will appear as the same sized fish when it is farther away from the transducer. In doing so it also filters out some of the weaker sonar returns that some of the Humminbird users wanted to see. It has since been replaced by the SwitchFire menu – so you may want to update your software. Look under the Sonar menu tab.”

You right that it effects all of them the same way as the returns come in but the way humminbird displays them is also a factor. They are not displayed in the same manner as the other one. The way it is shown to us is not as distorted on 2d as it is on SI. There is likely some distortion but not worth changing it up on a trip by trip basis. Not science. Just oneams opinion.

JAnderson wrote:

Not science. Just oneams opinion.

You got that right.

Every other professional anglers opinion is match boat and chart speed. Leaving it on 10 all the time is bad advice if someone’s really trying to fine tune. Fine for you if you’re lazy, but don’t advise others on bad form.

I do disagree with Fishblood though in that length of the return does factor in. I can distinguish quite well bass, from more lengthy fish in rivers and lakes from the returns.

nhamm wrote:

I do disagree with Fishblood though in that length of the return does factor in. I can distinguish quite well bass, from more lengthy fish in rivers and lakes from the returns.

There are many variables at play for both length and height.

Assuming you are matching your chart speed to your boat speed, and the fish are not moving, or are moving the same speed…then yes, length will help identify size without a doubt!!!

However here’s the factors at play:
1) Fish’s velocity in relation to the boat
a) Fish swims parallel and with the boat
b) fish swims paralles and opposite the boat
c) fish swims in any direction besides paralles to the boat

In regards to height of object, much less factors at play. The fishes thickness will remain constant so long as the fish doesn’t go from horizontal to vertical. Becuase the sonar displays a return over time, if a fish swims up or down in the water column, but remains at the same angle, the thickness of the return will remain constant.

I was being too generic when i said the length doesn’t matter, but i don’t often consider it unless it is a perfect arch and i’m matching boat speed to chart speed. Otherwise those factors are a lot of why you see the non-arches that you do see when matching chart speed to boat speed.

I guess my point is that all you can do to get the good “arches” is match chart speed to boat speed and pass over fish who want to behave for an arch on the 2d. From there it’s adjusting your sensitivity up to show anything from baitfish/thermocline/algae/cavitation or adjust lower for larger objects like fish or even just the bottom.

Why do you act like your on the water 2/3 of the year or something

Good stuff man!

nhamm wrote:

Why do you act like your on the water 2/3 of the year or something

Good stuff man!

Is it bad that i spend the other 1/3 preparing to fish or researching fishing?

nhamm wrote:

<div class=”d4p-bbt-quote-title”>JAnderson wrote:</div>
Not science. Just oneams opinion.

You got that right.

Every other professional anglers opinion is match boat and chart speed. Leaving it on 10 all the time is bad advice if someone’s really trying to fine tune. Fine for you if you’re lazy, but don’t advise others on bad form.

I do disagree with Fishblood though in that length of the return does factor in. I can distinguish quite well bass, from more lengthy fish in rivers and lakes from the returns.

1. Don’t be a dickhead nhamm.

2. After reading this I didn’t realize what I had written previously. I wrote that I set it on 10. I meant to write that I just set it on default which I believe is 2 or 3 so I’m having a much easier time following what fishblood is saying.

Sorry all for the confusion! You learn something new everyday!

And the more you know the more questions you have!!

FishBlood&RiverMud wrote:

And the more you know the more questions you have!!

Good info! I just started messing with chart speed this year, it makes a difference.

JAnderson wrote:

1. Don’t be a dickhead nhamm

Apology accepted.

Just glad to see the correct info confirmed. Many people read these posts weeks, months, years down the road to get an understanding of how things work. Hate to have the readers more confused at the end.

Everything changes when you go backwards… Then the whole program is cocked!