? for BTDT

I do get the white specks but I am not knowing about the white lines.  Would these lines be going all the way across your screen or more like dashes here and there?
 
Completely across the screen could mean a bad connection or some other problem you would want to talk to Humminbird about.  Dashes here and there could be floating debris or maybe interference from your motor or too fast of speed.

Slabfinder I wound agree with the transducer being mounted properly. Especially for the SI and DI.

One certain indication of improper install or angle is the loss of or noisy sonar screen under speed.

My first angle setting I lost the sonar screen at 7 MPH. I also had a terrible rooster tail when on plane.

Took several adjustments but I now maintain readings at full throttle.

Angle adjustment is important front to back as well as side to side.

OK now that you say white specks across the screen I'll go out on a limb here and assume 'the full screen'.

If that is the case, if you see the specks only when moving you are seeing noise from air or bubbles forming under the transducer. Angle or complete transducer install may be warranted. Try angle adjustment first.

However, if you see the specks while sitting, minor adjustment may be needed with power or filter settings.

Also, make certain the transducer connector at the head unit is properly seated.

You may try a different screen color also. I like the gray setting with the DI/SI.


Lastly, it is possible to see fish presented as white specks, running a split screen with sonar would verify if fish were present. Assuming the white specs are in the same area as the sonar coverage.

Keep in mind, I too am still learning so keep me updated.

Good luck.

Transducers can be a pain to mount. My Sylvan Backtroller is 29 years old, (and I've ripped out everything and rebuilt it from the bottom of the hull up), and when I bought it new I installed a transducer mounting bracket that was sold by Gander Mountain. This bracket is about a foot long and 4 and 1/2" high with rounded ends, and it has 3 square mount extrusions full length across the back. Square stainless steel nuts slide through the extrusions; your stainless, (or plastic) transducer brackets mount on the outside, and they can be slid sideways, or mounted slightly higher by using the middle and highest extrusion on the back. I originally had an Eagle flasher and the Eagle Mach I paper graph recorder transducers mounted flush with the bottom of the hull at the transom, and I filled in and smoothed the gap between the transducer and the hull to eliminate the rooster tail. The flasher worked well at speed, but not the graph. I now have my 'Bird 581 transducer mounted in the same spot, but no silicone is necessary to fill in the gap. No rooster tail and it works well from 0 to 30 mph and never loses the bottom. Since the boat is a backtroller, all the weight is in the very back, with two 6 gallon tanks, the 45HP Merc, the big size 27 deep cycle battery, and my 325 lb. fat ****, I have the transducer canted slightly to look straight down when I'm in the seat. As I contemplate getting the Helix 7 soon, I'd like to remount the bracket, (and I'd like to have a new one as the plastic is deteriorating), on the port side of the boat, 'cause I don't want the side imaging interfered with by shooting the signal sideways past the motor, but I've never seen that bracket advertised by any manufacturer since. So the plan will be to use marine plywood and extend it down on the outside of the transom so I can remount several times if necessary to locate the best position before I do a permanent mount.