[TG] [TG11] Element 7 HV screen - intermittent sounder clutter

[Stevenp]

Please help.

My screen operates in a normal way for a while and then for no apparent reason goes berserk with clutter. The only solution I have found is to restart, sometimes several times until the finder starts function again. I have tried every adjustment to sensitivity I can think of. Also I have noticed it stops reading the depth of the water and instead reads the depth of my shallowest downrigger weight.

This happens several times a day sometime with only a few minutes of good screen. I have included screen shots of what I consider normal and a couple of the bad screens. Even thought the bad screens show different colors I made no changes.

Do I have a warranty situation or is there something I have not thought of? I installed the transducer carefully according to instruction on my 13' aluminum boat. The finder has its own dedicated battery.

[Tom - Raymarine - Moderator]

Hello Stevenp,

I can only see two screenshots attached, but they tell the story pretty clearly. What's happening (at least in those screenshots - and by the way, thanks very much for attaching them, that's extremely helpful) is this:

Our sounders perform a dual function. They operate as fishfinders of course, but also need to provide a depth value for navigation. With this in mind, they err on the side of caution and treat the shallowest strong echo as the bottom. In your case the system is getting a strong-enough echo from the downrigger that it's deciding that it could be the bottom and is auto-ranging to that depth.
Once that happens, you are then prone to a second phenomenon, which is First Echo Interference. I've described this here and so won't do so again now, but that's what's causing the clutter in your screenshots. The appearance shown in your ScreenShot001 is very characteristic. This is definitely not a fault with your system.

You can remove/prevent First Echo interference by reducing the Ping Rate Limit, but a better solution would be to prevent the range-change which is causing the FEI in the first place simply by switching to Manual Range. If you do this, and range to the right depth to keep the bottom in view, then that will prevent the interference/clutter completely.

For anyone else reading this - if you were wanting to range to shallower than the bottom deliberately, to look for pelagics, then you can prevent First Echo Interference by reducing your Ping Rate Limit as described on the FAQ I linked to above.

Regards,
Tom