Questions/diagnosis - screen shots included

[DeepSouthTX]

Got my TZT3 connected to my main transducer finally. Was waiting on a mix and match 12pin from airmar and got it last week. Moved over from a Garmin setup and the transducer is the standard B275LHW airmar mix and match. Several questions - first ones related to the screenshot. The b275lhw top right - Dff3d bottom right. Speed 14knots. At any speed below 8 to 10 knts both sounders work as expected. At the 14knt cruise the dff3d acts as I would expect when getting bubble/turbulence from choppy seas. It looses bottom/return intermittently. The b275 does the opposite. It shows a massive spike in return. The tvg erases the top 50ft, tvg off and it goes the whole screen. They do not coincide with the dff3d return loss but the transducers are on different sides of the boat.
Depth bounces on the b275 with the returns hence the difference.



This is what it looks like as you accelerate from a troll up to cruise - right sides of sounder screens.




Other questions. Is the b275lhw opperating as chirp or traditional. It will only display 200khz and 53khw on the screen when in either high or low frequency. Should it not identify as chirp high or chirp low? Also it will not allow me to select any different frequencies that those 2. I can enter a different frequency in the transducers range but after about 5 seconds the TZT3 changes it back to either 53 or 200khz. It will only identify the ducer under the TDID. Under model it selects another transducer. maybe thats normal.



All of the screenshots were with it identified correctly by the TZT3. The above screenshot is just for reference.

 

[Snips]

DeepsouthTX,
Thanks for posting the screen shots.
On the TZT3 I can see the seabed disappears 100% of the time on 200Khz when the spikes are there and around 90% of the time on the 50Khz side. If the bottom comes back at slower speeds this points to turbulence. I noticed that the bottom was pretty flat which indicates that the seas were pretty mild on this day, normally you can expect more turbulence on a rougher day. Do you have trim tabs? If so, I would try seeing what effect they have on the sounders performance next time you are out. Below is an older screen shot but it is still a good example of how a vessels trim can affect performance while running.

Snips

 

[DeepSouthTX]

the boat does have tabs. i hope thats not the issue because it wont hardly plane with them up and suffers from an even higher than normal bow up attitude. both transducers are a little aft of midship and the tabs are 15ft behind then. could u still have turbulence with tabs that far back from the fairings? the sea state was 2ft, gulf of mexico.

 

[Snips]

DeepSouthTX,
The tabs aren't directly effecting the transducer but are affecting the trim of the hull. On the screen shot that I posted having the tabs down bought the bow down. As you can see the bottom was much better but the vessel lost 7 knots in doing so. In the end they were able to find an angle that didn't cost them to much speed and still had acceptable sounder performance.

Snips

 

[DeepSouthTX]

Snips. I will do as you suggested and see if the tabs are the issue and report back. Thanks for the suggestion.

Do I not have the ability to set a single frequency with the TZT3 internal sounder? Its not looking like it unless this is hidden in an area I have not discovered.

 

[Snips]

DeepSothTX,
The ability the pick the center frequency (for 1kw transducers) didn't make it into this first SW version of TZT3.

Snips

 

[DeepSouthTX]

Snips, I tabs up down and mid with no effect on sounder return. The transducer location looks good but I still must be getting turbulence. Getting it as well with the dff3d and its in the same area opposite side of the boat. I have had a handful of planing offshore boats and the only time I had a really solid return at speed was with a transducer I mounted on the keel. Right in the centerline. This winter when the boat is hauled I am going to take a look and see what my options are for moving it to a more optimal position.

 

[Quitsa]

Snips. I will do as you suggested and see if the tabs are the issue and report back. Thanks for the suggestion.

Do I not have the ability to set a single frequency with the TZT3 internal sounder? Its not looking like it unless this is hidden in an area I have not discovered.

The trick that I posted in another topic does work. Go into transducer setup, choose "Manual" and set it as a 1kW 200Hz. When I do that, the sounder display shows 200Hz instead of the 170Hz center CHIRP frequency and the picture changes so I am pretty sure it is in fact transmitting on a single frequency. What you can't do as with some other brands is choose a specific frequency within the CHIRP band other than 200Hz (or 50Hz for low).