Garmin Striker 4 can't see through vegetation?

[Great White Fisherman]

So I just hooked up my Striker 4 today and took it out for a spin. Love the details and features but a couple things don't make sense. 

 

1. I know the depth of the pond I'm scanning and at no point did it ever come close to reading that depth. From looking down and comparing with the graph, it thinks the tops of the hydrilla that covers the entire pond is the bottom and even shows red as a strong return. Why would vegetation be strong return and why can't it see the actual bottom. Changing the depth range doesn't show any obvious difference between the returns of the hydrilla and the returns of the bottom so I can't even tell where the bottom is on the screen and use the depth scale to measure it manually. What's the deal? 

 

2. I noticed something new on this units graph that my previous Piranha Max 4 didn't have. From the depth of 0 to a varying depth of around 1-2ft all around the pond, there is red as if there is something there floating at the top of the water but I can see there is not. What is it picking up??

 

Update: I've fixed #2, found a setting I didn't see before to show/hide surface noise

[J Francho]

Time to read through the manual and learn about a couple features: reducing surface clutter and adjusting the sensitivity or gain.

[Great White Fisherman]

8 hours ago, J Francho said:

Time to read through the manual and learn about a couple features: reducing surface clutter and adjusting the sensitivity or gain.

I've read it, watched videos, played with all the settings, all the gain levels show the surface clutter just more and thicker the higher it is of course. And going lower shows much less on the screen as in shallower. The only way the graph will dip to the 20s is on high but like I said, there's no difference to show a defined bottom between the vegetation and the mud

[WRB]

I am not familiar with Garmin sonar units, with that said your 1st unit worked OK on the same pond at this time of year?

Increassing gain will increase suspended clutter, even with Chirp units. My guess your unit is returning decaying vegetation clutter particulates on the surface and near the bottom that are holding trapped oxygen bubbles. Air is a very dense sonar signal return, i.e. red coloration.

However you should be able to see a echo return of the bottom regardless of decaying mater with the gain increased set on manual in lieu of auto ( not sure your unit can over ride auto settings?).

Tom

[Great White Fisherman]

16 hours ago, WRB said:

...holding trapped oxygen bubbles. Air is a very dense sonar signal return, i.e. red coloration.

I took this little tidbit about air bubbles and did some research. Turns out, hydrilla stems are packed with air cavities from the photosynthesis process. This would explain why it shows a strong return. On the same note, I always see bubbles rise up when a turtle is moving on the bottom so that leads me to believe that either the roots/tubers or the mud on the bottom is also packed with air bubbles giving a strong return as well. With this information, I've come to the conclusion that it is pretty much impossible to tell the bottom apart from the hydrilla. Maybe in the dead of winter when it dies off I can get a good contour. For now, I'll have to just go off of the softer returns underneath the red to guage the depth, just subract a foot maybe. This hydrilla business is just more and more annoying. Hard to fish it and now it screws up my sonar ?

[WRB]

Try to keep things into perspective, you have a lower end entry level sonar unit that is pre programmed to display averages from all over the country. To get accurate sonar data most experienced anglers learn to manually set thier units for water density, aquatic vegetation and structure density. Water density can change daily warmer, colder,  plankton, suspended debris etc. 

Chirp was added to recreational sonar in an effort to seperate targets from vegetation and structure, your unit doesn't have this technology.

I agree a sonar unit that can't display the bottom from vegetation is maddening, a basic depth reading should always be reading the lake bottom, not cover.

Tom

[Great White Fisherman]

8 hours ago, WRB said:

Try to keep things into perspective, you have a lower end entry level sonar unit that is pre programmed to display averages from all over the country. To get accurate sonar data most experienced anglers learn to manually set thier units for water density, aquatic vegetation and structure density. Water density can change daily warmer, colder,  plankton, suspended debris etc. 

Chirp was added to recreational sonar in an effort to seperate targets from vegetation and structure, your unit doesn't have this technology.

I agree a sonar unit that can't display the bottom from vegetation is maddening, a basic depth reading should always be reading the lake bottom, not cover.

Tom

Yes, finances dictate my options plus it's on a kayak which always has the potential to flip so I'm not too keen on having a high dollar piece of equipment on it lol. And this one does have Chirp and it's much crisper than on the same frequency without. However, options for setting any kind of density don't exist in the menu. I think I'll do much better when I go out to some cleaner fishing spots

[WRB]

Talk to the Garmin tech support, your unit should be able to read the bottom regardless of the cover type.

Tom

[Todd Driscoll]

No question, your unit will show the hydrilla and the true bottom.  First, you want to run a manual sensitivity setting around 55-70.  Then run a manual depth range 5 feet or so deeper than the bottom.  Here, you should be able to see the hydrilla height, along with the actual lake bottom.

 

This "issue" affects all brands of sonar and is just due to the thickness of hydrilla growth later in the growing season when it is at its thickest.  Running any brand in complete Auto mode over the top of thick hydrilla will result in what you are currently seeing.