FCV1150 TVG info

[Aaron Paisley-Kerr]

First time out yesterday with the new fvc1150. Going to take a bit to get turned in. But way easier then what I had before with better pictures already. So my questions after playing around with it lots yesterday. Is tvg level better higher or lower? Because I found if the tvg depth was set to deep the gain didn't work as good. And also noticed the target echo makes a difference between deep sea and squid. What is it actually doing to the picture and which would be the better pick?

Couple fish we got.

 

[FishTech]

Nice catch! Thanks for sharing the photos.
Your observations are correct about TVG, that is exactly how it is supposed to work. I'm going to post two snips from the manual related to TVG (Section 1.14) and Target Echo (Section 1.20.2) because it does a good job explaining it, simply. Let us know if you have further questions.

 

[Aaron Paisley-Kerr]

Nice catch! Thanks for sharing the photos.
Your observations are correct about TVG, that is exactly how it is supposed to work. I'm going to post two snips from the manual related to TVG (Section 1.14) and Target Echo (Section 1.20.2) because it does a good job explaining it, simply. Let us know if you have further questions.


View attachment 5812

View attachment 5813

No real help there. Only read that about 100times.

 

[Titanic II]

TVG is simply GAIN vs DEPTH. The setting changes the gain curve based on the depth you are fishing. Basically, less GAIN applied in the shallower depths and as you can see the GAIN ramps up as you listen for the deeper echoes. TVG 1 = more gain throughout water column. TVG4 = A flattened gain curve (linear). TVG8 = Gain curve is bowed opposite TVG1, less gain.

 

[Deep Blue]

Aaron Paisley-Kerr,

I noted in your first picture that there was a little noise on the fish finder screen. Now that could be caused of electrical, mechanical, or from another fish finder operating (using the same frequency) close to your boat. For better fishing performance, this should be addressed:



These are the following steps that I tell fish finder operators to use for getting the best fish performance:

1. Bring your boat to the depth that you commonly fish (more than 6 Meters (20ft). Do not attempt to do this in shallow water. The cone of the bottom coverage from the transducer is so small that the fish finder will only show depth.

2. Make sure AUTO features for Auto Sensitivity (GAIN) and turn off Auto-Range are set to OFF.

3. Manually adjust the Range to more that twice the depth. If you are in 15 Meters (50ft) than set the range for 30 Meters (100ft). You can even set the Range for three time the depth and get the same results.

4. Adjust the Sensitivity (GAIN) so that you can just see a faint second bottom echo, if your depth is 15 Meters (50ft), you should see an second echo at 30 Meters (100ft). This second echo is is because the fish finder signal is hitting the seabed and is being reflected back up to the transducer, then the signal reflects off the surface of the water and then again back down to the seabed where it's picked up by the transducer as a second echo. If your Sensitivity is set too high, then this signal will be distorted and you'll have trouble distinguishing bait from the fish.

5. Periodically re-adjust the Sensitivity with the fish finder when one or more environmental factors have changed. Like Water Depth, Water Temperature and/or Density, Water Clarity, or Water Salinity (this can change around outflows, river mouths, or bays and inlets).

6. Boat speed can also change the optimal desired settings. Less Sensitivity (GAIN) may be required if the boat is slowly drifting in calm water opposed to when the boat is trolling or cruising. Signal loss can happen at higher speeds, and in this case you may need to the use more Sensitivity (Full GAIN) to keep a consistent bottom reading.

- Deep Blue

 

[Quitsa]

Aaron Paisley-Kerr,

I noted in your first picture that there was a little noise on the fish finder screen. Now that could be caused of electrical, mechanical, or from another fish finder operating (using the same frequency) close to your boat. For better fishing performance, this should be addressed:

View attachment 5822

These are the following steps that I tell fish finder operators to use for getting the best fish performance:

1. Bring your boat to the depth that you commonly fish (more than 6 Meters (20ft). Do not attempt to do this in shallow water. The cone of the bottom coverage from the transducer is so small that the fish finder will only show depth.

2. Make sure AUTO features for Auto Sensitivity (GAIN) and turn off Auto-Range are set to OFF.

3. Manually adjust the Range to more that twice the depth. If you are in 15 Meters (50ft) than set the range for 30 Meters (100ft). You can even set the Range for three time the depth and get the same results.

4. Adjust the Sensitivity (GAIN) so that you can just see a faint second bottom echo, if your depth is 15 Meters (50ft), you should see an second echo at 30 Meters (100ft). This second echo is is because the fish finder signal is hitting the seabed and is being reflected back up to the transducer, then the signal reflects off the surface of the water and then again back down to the seabed where it's picked up by the transducer as a second echo. If your Sensitivity is set too high, then this signal will be distorted and you'll have trouble distinguishing bait from the fish.

5. Periodically re-adjust the Sensitivity with the fish finder when one or more environmental factors have changed. Like Water Depth, Water Temperature and/or Density, Water Clarity, or Water Salinity (where this can change around outflows, river mouths, or bays and inlets).

6. Boat speed can also change the optimal desired settings. Less Sensitivity (GAIN) may be required if the boat is slowly drifting in calm water opposed whe the boat is trolling or cruising. Signal loss can happen at higher speeds where you may need to the use more Sensitivity (Full GAIN) to keep a consistent bottom reading.

- Deep Blue

I have been using that method of adjusting gain for many years. One thing that I find puzzling using the TZT 3 internal sounder is that if I set the gain manually using the faint second echo method and then switch to "auto", the gain will clearly be set a lot higher, The second echo will be very distinct, hardly "faint." Why is the auto gain so much higher than what is considered correct with manual gain?

 

[Deep Blue]

Quitsa,

When using AUTO Gain, this feature has "pre-sets" that are pre-programed in the TZT3's internal sounder software when using the AUTO Gain. From me, I only like using AUTO Gain for navigational depth when underway. However, once you are on the fishing grounds, I still like to control the Gain Manually and use it to fine tune the sounder for those fish targets.

- Deep Blue

 

[Aaron Paisley-Kerr]

TVG is simply GAIN vs DEPTH. The setting changes the gain curve based on the depth you are fishing. Basically, less GAIN applied in the shallower depths and as you can see the GAIN ramps up as you listen for the deeper echoes. TVG 1 = more gain throughout water column. TVG4 = A flattened gain curve (linear). TVG8 = Gain curve is bowed opposite TVG1, less gain.

Thanks that's kkns of what I was thinking

 

[Aaron Paisley-Kerr]

Aaron Paisley-Kerr,

I noted in your first picture that there was a little noise on the fish finder screen. Now that could be caused of electrical, mechanical, or from another fish finder operating (using the same frequency) close to your boat. For better fishing performance, this should be addressed:

View attachment 5822

These are the following steps that I tell fish finder operators to use for getting the best fish performance:

1. Bring your boat to the depth that you commonly fish (more than 6 Meters (20ft). Do not attempt to do this in shallow water. The cone of the bottom coverage from the transducer is so small that the fish finder will only show depth.

2. Make sure AUTO features for Auto Sensitivity (GAIN) and turn off Auto-Range are set to OFF.

3. Manually adjust the Range to more that twice the depth. If you are in 15 Meters (50ft) than set the range for 30 Meters (100ft). You can even set the Range for three time the depth and get the same results.

4. Adjust the Sensitivity (GAIN) so that you can just see a faint second bottom echo, if your depth is 15 Meters (50ft), you should see an second echo at 30 Meters (100ft). This second echo is is because the fish finder signal is hitting the seabed and is being reflected back up to the transducer, then the signal reflects off the surface of the water and then again back down to the seabed where it's picked up by the transducer as a second echo. If your Sensitivity is set too high, then this signal will be distorted and you'll have trouble distinguishing bait from the fish.

5. Periodically re-adjust the Sensitivity with the fish finder when one or more environmental factors have changed. Like Water Depth, Water Temperature and/or Density, Water Clarity, or Water Salinity (this can change around outflows, river mouths, or bays and inlets).

6. Boat speed can also change the optimal desired settings. Less Sensitivity (GAIN) may be required if the boat is slowly drifting in calm water opposed to when the boat is trolling or cruising. Signal loss can happen at higher speeds, and in this case you may need to the use more Sensitivity (Full GAIN) to keep a consistent bottom reading.

- Deep Blue

Not really a answer to my question in the first place. 3

Iv got no problem with that little bit of noise. Would prefer some noise over missing fish altogether.

 

[Deep Blue]

Aaron Paisley-Kerr,

OK...Lets try this. <deep breath>

First, lets cover the basics. Lots of people read this forum, see this post and my not know: TVG = Time Varied Gain. Meaning the more you increase the fish finder's (or a sonar) GAIN, this value will get stronger by time which is also another metric for distance. Another way to look at it would be from the surface of the water, all the way down to the seabed. TVG will increase the GAIN of the fish finder (or sonar) as it goes deeper.

So why is this feature? Its a way to decrease the amount of Clutter within the water column without decreasing the overall sensitivity of the sounder when searching for fish at or near the seabed, or at deeper depths. Traditionally, without any TVG to decrease the Clutter on the screen you would either have to lower your GAIN or increase the Clutter control. But by using TVG it allows the fish finder to maximize the GAIN at the deeper depths, but will provide you less sensitivity at or near the surface.

The TVG settings for the following fish finders like: DFF3, FCV295, and FCV1150 use TVG Distance along with TVG Level. Again, this level will control the sensitivity of the TVG: So more is more, and less is less. But the distance control will allow you to set the distance you want the GAIN to be maximized at. So, if you are fishing in 600 ft. (182 meters) of water and you set the TVG Distance to 600 feet, the TVG level that you choose will be maximized at 600 ft. (or 182 meters). The shallower you go then the less sensitivity that you're going to have. So, you must be careful to pay attention to the TVG distance, for example. Say you set your TVG level to 8 and then you set the TVG distance to 600 ft. (182 meters). But lets say you are only fishing in 300 ft. (91 meters) of water. With this combination your TVG Gain Level would not be maximized until the 600 ft. which is deeper than what you are currently fishing in. So, with this combination you would never see your GAIN maximized so you fish finder would not be optimized.

Does this explanation sort of help.? You also have to keep in mind the water depth, the condition of the seas, water temperature, and salinity. This all plays into the settings of the fish finders and sonars.

- Deep Blue