Electronics Help - metering fish in deep water

[mobilereef]

Please help. I am looking for someone who knows the Furuno GP 1850 model GPS / Plotter / Sounder. I have a 1kw through hull transducer. It is tough for me to meter fish in deep water, for example around kelp paddy. I am positive this is because I do not know the correct setting. The unit works great as long as it marks the bottom, but anything over 700 feet it seems to bounce around a lot between depths and not show any fish in the water column. I switch between 50khz and 200 kHz, and still do not see the fish on the meter, even if I know there are fish there.
Can anyone help? Thanks if so.

 

[Salty Paul]

Please help. I am looking for someone who knows the Furuno GP 1850 model GPS / Plotter / Sounder. I have a 1kw through hull transducer. It is tough for me to meter fish in deep water, for example around kelp paddy. I am positive this is because I do not know the correct setting. The unit works great as long as it marks the bottom, but anything over 700 feet it seems to bounce around a lot between depths and not show any fish in the water column. I switch between 50khz and 200 kHz, and still do not see the fish on the meter, even if I know there are fish there.
Can anyone help? Thanks if so.

Just a suggestion, but you can download the user manual from Furuno USA, if you do not have one. Another option is to set the range on the meter to say 0-200 ft, etc. here is the link:

http://www.furunousa.com/Products/ProductDetail.aspx?product=GP1850

Furuno USA contact,they have great customer service;just give them a call.
http://www.furunousa.com/Company/ContactUs.aspx

Salty Paul

 

[sickcat]

+1 on setting the range manually to 200-250 ft.

If your drifting turn off the noise rejection off. Set the gain manually. To get a starting point go to a place where the bottom is about 100-120 ft. Manually set the range to twice the depth plus 20 ft (if the bottom is at 100 ft then set the range at 220 ft) and turn the gain up until you see the bottom at 100 ft clearly and you see a fainter but consistent return at 200 ft. Make a note of what that gain setting is and then use that as your starting point for setting the gin offshore.

 

[mobilereef]

+1 on setting the range manually to 200-250 ft.

If your drifting turn off the noise rejection off. Set the gain manually. To get a starting point go to a place where the bottom is about 100-120 ft. Manually set the range to twice the depth plus 20 ft (if the bottom is at 100 ft then set the range at 220 ft) and turn the gain up until you see the bottom at 100 ft clearly and you see a fainter but consistent return at 200 ft. Make a note of what that gain setting is and then use that as your starting point for setting the gin offshore.

This is very helpful. I have the manual, but it does not offer practical experience suggestions. This is exactly what I needed. Thank you so much

 

[Albiebac]

It looks like you're getting pointed in the right direction, I have the same unit, but only with a 600watt transducer, and it does well offshore, so you should do even better.
For me, while fishing offshore, I run at 200kHz, set the range to 200ft (anymore I figure is too deep), and the gain to a point where I'm just starting to get noise, usually from the thermocline. Below is a picture of 20# YFT under the boat. While running, there is too much noise, but trolling it works well.

yft1

• Albiebac
• Aug 10, 2015

 

[Surg]

While fishing offshore it's prefered to run dual frequencies or 50 khz because the LF will have a wider cone angle under the boat. In 200 KHZ you pretty much have to be right over the target to see it. It is critical to set the range to manual between 200'-250'. Best of luck.

 

[MATTANZA]

put it in fishing mode/automatic. see what you get , then dial in on manual model to match. with a 1k td you should get great readings.