Sonar interfernce on Lake Chelan

[hutchings]

I was fishing north of the Lake Chelan Yacht Club on Saturday March 25th. My sonar, Lawrence Elite 7, was constantly getting interference to the point I couldn't see if I was marking fish or not. Whether I was close to another boat or not made no difference. Later I moved down by the blue roof condos and other spots and it worked as expected. Has anyone else had this experience?

[Larry3215]

Did you happen to get a screen shot you can post? That would help in figuring out the problem.

Did it change at all as other boats were closer or further away?

Were you using an electric trolling motor at the time?

[hutchings]

I didn't think to take a screen shot at the time. The interference might have increased some when close to another boat but the majority of the interference was constant. No electric trolling motor or other electronic devises were in use. There was a water pump-out station operating on the shore opposite the yacht club.

[Larry3215]

Its possible the pump station motors were generating some sort of noise that would cause your problem, but it sounds like at least a part of it was another boat or boats operating on the same frequency as your sonar. Depending on how much power the other boat is putting out, it can travel quite a ways. Could even have been a boat or boats in the marina.

I used to get that a lot when salmon fishing with the crowd off Point Defiance. My new CHIRP sonar seems really good at rejecting noise like that compared to my old one.

[Bodofish]

I'm going with Nessy........

[Amx]

...and her babies...

[hutchings]

I fish at Buoy 10 and Brewster where I'm constantly in the vicinity of other boats and deal with the intermittent interference it causes. But this is different, no matter how far I got from other boats the interference didn't go away nor did it decrease in intensity. Plus the fact that it completely stopped when I move down lake by the condos makes it even more puzzling. I will be back there this coming weekend and it will be interesting to see what happens. My money is on the pump station with Nessy running a close 2nd. Thanks for your time and the input Larry. I appreciate it.

[Larry3215]

If its the pump, it should get stronger as you get closer.

Unless you have some sort of intermittent electrical issue, thats most likely what it is.

[hewesbob]

That happens to me on Lake Wenatchee. When I get close to one certain house my Garmin totally wacks out. I have to shut it down and restart it after we are past that one house, crazy. This has happen the past three years.

[Larry3215]

That happens to me on Lake Wenatchee. When I get close to one certain house my Garmin totally wacks out. I have to shut it down and restart it after we are past that one house, crazy. This has happen the past three years.

Interesting! I wonder what they could have that would cause that? It must be something that is sending electrical noise or sound signals into the water in some manner.

They could have one of those Invisible Fence things buried in the ground, but I think they operate on much lower frequencies than our sonar. Possibly a noise spa or pool pump? Not sure how that kind of noise would get into the lake though unless is was a spa out on a dock maybe.

Sorry, I get side tracked thinking about odd tech issues like this...

[kodacachers]

[TrackerPro16]

I wonder if a short into the water would do that? Might be something they should know about if it is...

[G-Man]

I'd bet on a pump motor of some sort. To become more efficient, more and more electric motors are being controled using pulse width modulation, the same technology that higher end electric trolling motors use to prolong battery life. If you have fished in the Sound and were near a ferry leaving port, you probably have seen the this type of interference on you sonar as they also use this tech in their diesel/electric propulsion system.

[Fishin'Daze]

This may sound simple but check to make sure your depth setting is deep enough. I also experienced what seemed to be interference once when fishing a deeper than normal lake I usually fish. After checking my sensitivity and a few other settings I realized that my depth setting was to shallow. I reset to the proper depth and unit worked great. Sometimes it may be a simple fix - good luck.

[downriggeral]

I have found using the 83 kh setting really helps on Chelan. The sonar MUST lock on the bottom for the sonar unit to work. Hope that helps - Alan

[hutchings]

Alan (downriggeral) hit the nail on the head. After reading his suggestion on Saturday night I adjusted the setting to 83kh and the problem went away. I didn't have much time to test it out for very long before the wind blew us off the lake. Thanks to all for their inputs and suggestions. I was really hoping we had found Nessy.

[Chetco]

Heck just get old and you can't hear all the background noise.