Active Target Transducer Height and Angle Offset Questions

[Thamelau]

Which direction do I adjust the angle offset? If my trolling motor is tucked 2 degrees, then do I set it +2 or -2?

Can you have your transducer set to high on the trolling motor, or as long as it is in the water, you are good?

[Basshopper]

1st if the TM is back towards the transom then set negative number I would start with 1 for such a small deg.

2nd the transducer on AT should be7 or 8" from top of the TM motor to the bottom of the AT bracket. The lower the better.

[Thamelau]

That was a hypothetical number honestly. I have a digital angle finder, and planned on using it to find the actual offset angle. Is there a reason to set the offset any differently than the actual offset angle?

I also originally had the transducer set like 5" from the trolling motor barrel. I set it higher in hopes to make my cone larger at the bottom to assist seeing my bait. The more I think about it, the more I think the small change it height of the transducer is negligeable. I thought I seen someone online say to mount it as high as possible, leaving it underwater.

[Basshopper]

The angle offset is just a temp solution. Your best solution is to find the actual cause of the angle if less or more than 90degrees to the water. Most is caused by the TM mounting on a hooked nose boat. To do it right find the root cause and fix that better off long term. Including it fixes the images of any other transducers on your TM also. Of course the real fix is if you have a point 1 on your boat go out stand at the bow read the atltiude Pitch, Put it on the trailer jack up the traler to that pitch then measure your TM shaft deployed over the side and get that angle. Then shim TM mount accordingly. If you can see out in 20 ft of water to 100ft in forward view then your good you can tweak to get the bottom out to 100ft. Its all geometry to get the best image on Forward facing sonar.

[Thamelau]

For anyone that may be looking into this information and come to this thread.

I raised my Active Target Transducer so it is a few inches under the water while I am fishing. I also measured and the trolling motor is tucked under the boat by 1.9 degrees. I set my offset angle to -1.9 on my Active Target Installation setting (settings-sonar-active target installation).

I took it out yesterday and tested it for the first time. I was amazed. I went from rarely being able to see my bait to being able to see it regularly 50' out in 10' of water. This was with a 1/8oz tungsten jig head and minnow bait.

Since I was shallow I had the sonar 1 more click forward than the recommended forward mounting on the bracket itself. I had the noise rejection turned off, whatever they call sensitivity (contrast maybe?) turned up to the point that I could see clutter, but distinguishing my bait and fish was not too difficult. I would guess this setting comes down to personal preference on clutter as well as stuff floating in the water. I am also looking at a 9" screen mounted on the deck, so a larger screen would make things easier.

Hope this was helpful.

[Basshopper]

When you go to shallow water instead of a transducer adjustment which takes away from another place just do temp angel offset go another -deg it would work better if you actually leveled your bracket or TM 2deg and used the angel offset for just shallow adjustment or looking under docks or weedbeds. Lots can be done for special situations. Raising your transducer is the opposite that you need for shallow water.

[Thamelau]

When you go to shallow water instead of a transducer adjustment which takes away from another place just do temp angel offset go another -deg it would work better if you actually leveled your bracket or TM 2deg and used the angel offset for just shallow adjustment or looking under docks or weedbeds. Lots can be done for special situations. Raising your transducer is the opposite that you need for shallow water.

I totally agree that getting my trolling motor shimmed up would be the ideal fix. However, with how well this worked for me, I probably won't mess with anything until it's time to change trolling motors.

I don't understand why raising the transducer would be bad. It gives you the widest field of view, cuts out on any interference you may get from the trolling motor, and appears that it helped keep the beam from being blocked by the trolling motor at all.

[rfdong]

Isn’t just raising the transducer a click up or down the same? Or is that a larger adjustment? I guess I don’t quite understand the difference? Just trying to understand what is accomplished by angle offset vs leveling the actual TM?

[Kdixer]

Angle offset did not seem to change the angle of the sonar signal emmited from the transducer when I tried it. It merely changed the angle of the image position on the display. Adjusting angle offset would not let me detect my lure towards the water surface.

[Thamelau]

I don't know all the specifics. In my mind, the angle offset would not have the ability to change the actual angle of the beams. The sonar units are hard mounted in the transducer, which is hard mounted on the trolling motor. It is correct that it should only adjust the screen. This helps because if you are cutting off the backside or topside of your image, it will have the screen show it.

The perfect solution is to make your trolling motor level.

Rotating the unit forward or back 1 click would change it more than a couple degrees. I wanna say we are talking about 10 degree adjustments at that point.

[78Staff]

Angle offset did not seem to change the angle of the sonar signal emmited from the transducer when I tried it. It merely changed the angle of the image position on the display. Adjusting angle offset would not let me detect my lure towards the water surface.

When I was running AT, I found the same - adjusting the angle value in the settings only "shifted" the position of the image on the screen, which wasn't very useful imo. I posted on it in one of the many AT angle/missing slice threads a while back with some images as well I think.

EDIT - here's the thread - AT2 transducer angle/mount head scratcher...

[Johnnyred]

Straight from Lowrance on AT: "Ensure the transducer is positioned correctly per the operation manual. Note: For maximum sonar coverage, it is recommended to position the transducer 8-18” below the water line."

Leveling your TM shaft not just front to back but side to side also is for sure what you want in a perfect world to optimize AT coverage. Some might encounter problems with their TM mounts binding, latches either not engaging fully or not wanting to disengage to stow, if "shimming" the mount. A wedge might be a better solution... but even then trying to compensate for anything over a small amount of degrees presents potential problems with torquing the bolts, clamping pressure, etc. Using wedge washers along with a mount wedge to compensate might help.

I realize some/many/most have shimmed and wedged with good results. Prolly comes down to your application, TM brand, mount type, how many degrees you try to compensate for, other stuff.