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Full Version: [TG11] Element 9HV Bad Sonar Readings
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I few months ago I purchased a Element 9HV for a new kayak I got from Old Town called the Sportsman AutoPilot 136 which has a Minn Kota spot lock trolling motor integrated into it.

For a while now the sonar imaging I've been getting from the Element has been bad. I have this constant "line", for lack of a better word, that shows up. It's more pronounced in shallower depths that it is when deeper but its still there. The transducer is mounted ahead of the trolling motor and I thought maybe it was some interference from that. So I pulled the motor out of the hull and paddled around and still had the same results. I've reset the sounder many times but the sonar imaging just isn't what I'd expect it to be and this issue still persists. For comparison, I own an Axiom 9 on my Hobie kayak and I get perfectly clear sonar imagines with it not to mention I've been with the Raymarine brand for years now so I know what images should look like. Just can't figure out why this is happening and it's a real issue. I've had to manually turn down the gain to around 30 just to get rid of it but then I am missing bait and actual fish marks as a result. It's almost unusable. Hoping to get help to fix this so I can keep it.

Screenshot 6 & 7 is the default all to auto and then my manual settings for a 1 for 1 comparison. You can see the line at about 10' and then at the bottom you can see it again coming off the flat bottom. All screenshots are from Lake Michigan.
Hello chicityyaker,

This looks like Second Echo interference to me. This is a phenomenon that can happen when you have:
  • flat water conditions
  • a strong bottom echo
  • a sensitive sounder

I've written a description of what's happening on this FAQ.

To make this less prevalent you can turn on or increase the values of Menu > Settings > Sounder > Interference Rejection and 2nd Echo rejection. To eliminate it completely at the expense of slower scrolling you can decrease Ping rate limit in the same menu. What reducing Ping Rate Limit will do is space out the pings that the sounder transmits and allow time for the echoes from the last ping to die away before listening for the next one. You will find that over the space of <5 increments in the Ping Rate Limit the 2nd echo interference will significantly reduce and then disappear completely. Use the highest Ping Rate Limit that you can and still remove the interference. You will find that the specific value that does this will depend on the depth in which you fish, but will probably be somewhere between 15 and 30.

This isn't a fault with the system, it's just an unavoidable result of the conditions and the sensitivity of the system and that it's trying to get as many pings into the water as possible for best sonar detail.

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