Thread: Just can't get my Lowrance side scan to work right.....

I've watched at least a dozen "catch crappie using sidescan" type of videos and I can perfectly understand what they're showing on the videos. I see and properly interpret the outline of the dock, the floats on the dock, the pontoons on a pontoon boat and even the crappies under the dock. I get the whole shadow thing and using the proximity of the shadow to determine the depth of the fish that you're seeing, but I don't see any of that stuff on MY UNIT. Very frustrating and I'd love to know what I'm doing wrong.

I did just watch one video where the guy suggested that the triple shot transducer should be kicked up roughly 15 or 20 degrees above flat and I don't think mine is anywhere near that. Going off of memory, I'm guessing that my transducer is mounted at very close to the same 90 degree angle as the hull of the boat. Could it be something as simple as that? I'll get around to experimenting with that some day, but obviously I don't wish for my downscan or sonar to suffer if I change the angle of the transducer and I believe that my sonar and downscan are working as expected.

The following diagrams are for Humminbird. Lowrance doesn’t publish their SI beam angles but we can assume Lowrance beam angles are similar ...


Notice the 800kHz SI beam doesn’t cover to the water’s surface like the 455kHz SI beam does.

This is why you are not seeing the floats on the docks ...

Note that the lower 455kHz frequency doesn’t have as much detail as the higher 800kHz frequency. This is just a natural trade off in Sonar technology ...
——-

Now to detail ... :

Lowrance doesn’t have a Chart speed adjustment for SI like Humminbird does so to get the best ratio of boat speed to Lowrance’s “fixed” Chart speed (to accurately plot the data into the SI image) - your boat speed should be about 3-4mph.

Slower boat speed than that will stretch the data in the SI image until it may be unrecognizable.

Conversely boat speed faster than that will compress the data in the SI image until it also may be unrecognizable ...

Rickie

That's interesting and helpful. Even when I had it at 455khz, I don't recall seeing the docks and boats well, although I was able to see them at least barely to determine where they were. Odd that I'm not seeing sticks and brush better with the 800khz though (not to mention fish). I'll keep reading and will try to find someone that knows Lowrance side scan to give it a look one of these days because it's killing me that I can't get out there and really spend some time to find some fish on docks.

Level your transducer with the angle of the boat as you are scanning. Pick a spot on the boat to put a level. Travel at your normal scanning speed.

Use something (I used 1/4" fender washers) to put under the level to get it level. Count the number of washers you used.

When you get home, put the level in the same spot, put the same number of washers under the level, then jack up front of boat until your level shows level. Level the transducer to that angle of the boat.

That said, the angle may change with fuel and tackle load, number of passengers, etc.

I also adjusted mine a little side to side because of the list, that was just a guess.

As mentioned, the transducer needs to be parallel with the waters surface. How shallow is the water you were scanning in? If your transducer is mounted correctly back the range up to 40-50' and try it again

Originally Posted by justinp61

As mentioned, the transducer needs to be parallel with the waters surface. How shallow is the water you were scanning in? If your transducer is mounted correctly back the range up to 40-50' and try it again

This is a deep lake, but most of the docks I've been scanning have been in 15-30 feet of water I'd guess. I did switch back to 455 Khz yesterday and was able to start seeing the dock floats and boat lifts at least. I didn't mark anything that I presumed to be crappie under the docks, but it was a really windy day and I didn't make a very concerted effort at it. I may head to a lake next week that has a MUCH healthier crappie population, just so I can spend some time staring at side scan and figuring it all out. For what it's worth, I did scan at 40-50 feet almost all the time. Occasionally if I was in really deep water I'd switch to 60 feet, but that was the upper limit and that was rare.

So, I wanted to give an update since a few of you were kind enough to offer me some tips and advice. I've been having some issues with the unit that weren't really related to the side scan and I called to speak to a tech today. After hearing my issues and seeing some screen shots, he advised me to do a soft reset of the unit, then give it a try. So I did the soft reset, then ran the boat straight to the lake to see if it worked. Well, the unit was working MUCH better than it had been. I put it on side scan and started seeing things that I'd NEVER seen before on this unit, so apparently my software was messed up or there was something wrong with my hardware. Problem is that while it did improve the performance of the unit, it didn't resolve all that was wrong with it and I THINK that the unit's still under warranty, so hopefully it's going back soon for repair or replacement. I can't wait to get it back though because now for the first time ever since I've had the unit, I actually have some confidence that the side scan will become helpful to me.

Have you updated the software on the unit? That sometimes corrects problems in the software.
You can also do a hard reset This returns every thing back to when it was new.

If you decide to do a hard reset be sure you download all your waypoints to an SD card so you can reload them after the hard reset.