Furuno GP 1870 Gain Control using 200Hz

[Aquatica]

Hi all,

I'm new to the group so first time post.
Question I have is that I have a GP 1870 Sounder/plotter running a P66 transom mount transducer and when I use the unit in full manual mode in 200Hz , I cannot adjust the gain to max(100%) without it showing anymore noise/clutter. The boat is stationary and the picture of the screen from the top of waterline to the bottom is very clear. It will show schools of fish, but I cannot adjust the gain to possibly see more fish.
If I change to 50Hz and I adjust the gain to max, the screen becomes noisy/cluttered which I can tune out with less gain or by adjusting the clutter etc.
Has anyone else encountered this at 200Hz setting?
Appreciate your replies.

 

[Snips]

Aquatica,
If you really want to you can adjust the 200khz side TVG and Echo offset.

Snips

 

[Aquatica]

Hi there,
Thanks for that. I went through my settings and found that the TVG for the 50kHz was set to 3, BUT the TVG for 200kHz was set to 0. I have changed it to 3 and ran the unit on the simulator mode and already has made a difference.
See how it performs on the water.
Thanks for the advice