DFF-3D External KP

[Quitsa]

I noticed looking at the software history that "automatic KP over network" was added in v 1.04 of the DFF-3D software but it says when used in conjunction with a DFF3.

I assume that means it isn't available for the internal TZT 3 sounder with or without a DI-FFAMP? Why not? That would be so much easier and cheaper than running the KP cables.

 

[Magnetron]

The Part no. "TZT-3KP-F3D" is the proper TZT3 / DFF3D KP CONNECTION KIT.

See: https://furunousa.com/-/media/sites/fur ... manual.pdf

Hope this helps, :sail

- Maggy

 

[GUS]

Is there any chance that Furuno can provide recommendations or guidance on when the External KP would be helpful (which transducers frequencies might interfere with the DFF-3D and vice-versa) and which won't.

How do we decide if the External KP is needed or would be helpful?

 

[Quitsa]

The Part no. "TZT-3KP-F3D" is the proper TZT3 / DFF3D KP CONNECTION KIT.

See: https://furunousa.com/-/media/sites/fur ... manual.pdf

Hope this helps, :sail

- Maggy

Thanks. I was aware of the availability of the cable kit. It is rather difficult for me to install the cables because it would require taking out the MFDs to get to the sounder box -- would have been nice if the external KP cable had been available when I installed the system.

That's why I was intrigued by the language in the software history that makes clear that a network solution for KP is possible. I guess I don't understand why the software can't do the same with other sounders besides the DFF3.

 

[Magnetron]

Is there any chance that Furuno can provide recommendations or guidance on when the External KP would be helpful (which transducers frequencies might interfere with the DFF-3D and vice-versa) and which won't.

How do we decide if the External KP is needed or would be helpful?

Great question! :cool

Typically the guidance is user preference. :?

Say on a boat that has the 165T/275LHW combination multibeam transducer with the elements from a B275LHW CHIRP.... The 275LHW CHIRPs in HF between 150 to 250 kHz and the 165T echoes at 165kHz so right at 165 kHz (at the start of the 275 sweep) will be interference as two sounders echo the same note. This typically shows up as streaks in the fish finder.

[275 sweep ->]
150 kHz ------| 165kHz |----------------------------------------------------------250 kHz

Now some don't like the interference, or you're concerned with the two obfuscating a fish return well that's why the KP kits exist - to eliminate that noise. However the trade-off is in order to time the two XDRs there's a slight performance loss in the returns. If you can handle the slight interference in your returns in-exchange for real-time performance than you may hold off on the KP kit.

Hope this helps, :sail

- Maggy

 

[Quitsa]

I should add that based on my two years of experience with a DFF-3D and a B175H CHIRP transducer driven by the internal TZT 3 sounder, there will definitely be visible streaks of interference on both sounder displays. If you set the interference filter at "High" on both sounders, the interference marks will go away. It does not seem to hurt the performance in showing fish very much. Of course it is not so easy to determine the absence of something so the interference filter may be having more of an effect than is obvious. The external KP seems like a cleaner way to deal with the issue.

The other thing you can do that will help is to set a custom frequency range for the HF CHIRP that starts above the 165Hz used by the DFF-3D. This works less well than I would have expected and is not a s successful in reducing the vertical streaks from the interference as setting the filters on high.

I find it a bit "un-Furuno like" that the company would offer the products knowing that a substantial number of DFF-3D users will also be running HF CHIRP sounders with overlapping frequency ranges. I don't know enough about sonar technology but wouldn't t be possible to have a tuned 165Hz filter in the TZT 3 sonar circuit so it would not transmit or receive that frequency and thus eliminate the two-0way interference problem? It's not like we are trying to use a Simrad or Garmin sounder with the DFF-03D and experiencing the issue -- it's two Furuno products interfering with each other.

 

[Johnny Electron]

Like the DFF1 and DFF3, KP might be possible with software over time with development. The DFF1/DFF3 software developed later that ability years later and it isn't as simple as one might like to think. You don't want to just apply it all the time because it does slow the sounding transmissions down. Customers who have installed the KP kit on the DFF3D sometimes find they would rather have a bit of interference than lose the speed they have grown accustomed running without. Have you tried the current KP kit or is this an assumption of greener grass?

 

[Quitsa]

Just looking for greener grass as you say. The location of my DFF-3D box means installing the KP cables require removing the beautiful "glass bridge" style flush mounted. panel for the TZT 3s the boat builder did for me and having to redo the sealing around the MFDs.

That's interesting about the transmission speed. I did not know that was a consequence of the KP synchronization. As I noted in my post, the interference filters do make the vertical marks go away and both sounders still show fish and bottom very well.

Thanks for the clarification.