Default Setting

[MikeR13]

I have CHIRP 275 transducer hooked up to my TZT. Was just curious as to what the default setting to the Gain Offset. I was getting a lot of interference or clutter when i was fishing in like 60feet and reduced the setting to -20. Seems to have cleared everything up with clutter set to 0 and gain at about 75. Just trying to understand what the Gain Offset does and what specifically does the STC feature do. Just wonder if anyone can add to what I've read about them.

Thanks

 

[Snips]

Mike13,
Thank you for your questions.
The STC (Sensitivity Time Constant) allows the user to control the receivers gain down to 15-20ft. Next time you can see how this works by setting the sounders range to around 30ft and then set the main gain control to 100%, this should saturate the display with noise. Now vary the STC control from 0-10 and watch what happens. As the STC increases you will see the strength of the shallow water noise decrease.

Now the Gain offset is exactly that, it offsets the starting point of the main HF/LF gain control. As you have seen, once you lowered the Gain offset to -20 that allowed you to have the Gain control at 75. Basically you lowered the starting point of the main control. The default setting is 0.

Hope this helps.

Snips

 

[MikeR13]

I will try that thank you...When you say set the range what function is that again (i don't have the screen in front of me but I remember setting it). I think my range was currently at 0 if i remember correctly. But i will try those settings as you referenced. Seemed like i was getting interference when the offset was at 0, especially when i was going over large rocks in the 30-60 feet of water. Otherwise the clarity is amazing with that transducer! Any additional functions i should try I'm all ears!

Thanks again

 

[Snips]

Mike13,
The range I mean is the sounder range, 0-30ft.
I am having a hard time trying to visualize what you mean by interference. If you are only seeing this when going over hard seabed's it could be a second/third echo that you are seeing. Below is an example of what it could look like. If you are seeing something like this you can change the TX rate (PRR) from 20 to 18 and it should go away.

Snips

 

[MikeR13]

Yes it looks something like that a mass of vertical dotted lines. Ill try and grab a screen shot next time I'm out. But I had totally forgot about second echoes....That is probably accurate as to what it is.