Garmin 75DV newbie question

[Balvenie]

Guys, I'm getting the vertical lines on my front unit....cant seem to find a setting (gain, interference etc)that will make it disappear.
What could be causing this ?
Unit is a Echomap DV 75 non Chirp with GT20 transducer mounted on the TM. I have a SV 75 Chirp unit at the consol.

[Larry3215]

What trolling motor?

Does the console unit have a separate transducer - on the transom maybe?

Does it go away when the trolling motor is off?

That interference could be from the trolling motor or the other transducer. Need to figure out which one it is first, then work on a fix.

[Balvenie]

What trolling motor? Minn Kota Maxxum

Does the console unit have a separate transducer - on the transom maybe? It does, transom mount GT-52

Does it go away when the trolling motor is off? No, also thought that could be it but TM doesn't seem to affect it.

That interference could be from the trolling motor or the other transducer. Need to figure out which one it is first, then work on a fix.

[Larry3215]

Im going to guess you're running the transom and front transducers at the same frequencies then. Try setting them to different frequencies and see how that does.

[Balvenie]

The front unit is set at - Traditional 200khz/DV 455khz.
Console unit is-Traditional "Chirp"/DV 455kh

I only get those lines on the front "traditional"view.

[Larry3215]

To test, try turning off the console unit and see if the lines go away. If they do, then its going to be a matter of changing the frequency on one of them to get rid of the interference.

[Balvenie]

Thanks....another newbie question....will changing the frequency negatively affect what I see on the unit ? ie: fish, structure, lure etc

[LWINCHESTER2]

You have multiple options. First, do you really need both operating at the same time? Console and TM. When you move from the boater position to fishing, just press the power button and stop the sonar if you want to leave it on.

You can set the frequency of the console unit to a manual frequency that does not interfere with the 200 at the trolling motor. You have to set them up manually but you can do that before you go fishing. You have from 150-240 to work with. I add them by 10's for the full range.

On the DV and SV you have 455 and 800 to choose from. The 800 may peter out on the SV in water 70 ft deep or more for showing fish.

[Larry3215]

Thanks....another newbie question....will changing the frequency negatively affect what I see on the unit ? ie: fish, structure, lure etc

Frequency selection can make a big difference in what you see - depending on the situation.

200 khz:
1)is looking at a smaller bottom area with a narrower cone
2)it will not penetrate as deep as lower freq's
3) it will give better resolution so you can see individual fish close together better than low freq's and smaller targets will show up better.

80khz:
1) wider beam so you see more area
2) penetrates deeper
3) Less resolution so things tend to get clumped into a single larger return and the targets have to be bigger or they dont show up.

CHIRP - is the best of both worlds at the same time plus a lot less interference.

If possible, keep the console unit operating on the CHIRP setting for the best over all performance.

[Ashton.r]

i've had this exact problem but mine is caused by my trolling motor, odd that yours seems to not be from the tm.