Correct DFF3 transducer profile for Airmar R109LHW (38–75 / 150–250 kHz)

[FV-PACO]

Hi everyone,

I’m looking for some guidance on properly configuring my transducer settings. I recently purchased a boat and am still dialing in the electronics. The boat is equipped with the following:

Electronics onboard:

• TZTL15F MFD
• Furuno Network Sounder DFF3 (28 kHz – 200 kHz)
• Furuno Multi-Beam Sonar DFF-3D (165 kHz)

Transducers:

• Airmar R109LHW (Low CHIRP 38–75 kHz / High CHIRP 150–250 kHz)
• 165T-B54 (165 kHz, used with the DFF-3D)

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Current configuration on the TZTL15F​

Under Transducer Setup Type = Model, the settings are currently:

Model Number

• 200kHz:50/200-1ST

High Frequency

• 200kHz:50/200-1ST

Low Frequency

• 50kHz:50/200-1T

Frequency limits:

• High Frequency Min: 196 kHz
• High Frequency Max: 205 kHz
• Low Frequency Min: 48 kHz
• Low Frequency Max: 51 kHz

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My concern​

I don’t believe these settings are correct for the Airmar R109LHW, but I could be mistaken.

From what I can tell:

• These appear to be fixed 50/200 kHz transducer profiles
• I do not see a specific R109LHW entry
• I also do not see a clear 38–75 kHz wide-beam CHIRP option

Looking through the available transducer lists, the closest match I can find for the R109LHW low band seems to be:

38kHz:38BL-15HR

However, since the R109LHW is a wide-beam CHIRP transducer, I’m unsure if this is truly the best selection or simply the closest legacy profile.

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Questions​

1. Is 38kHz:38BL-15HR the correct (or best available) low-frequency selection for an R109LHW on a DFF3?
2. Is there a more advanced or recommended configuration for wide-band CHIRP transducers when an exact model is not listed?
3. Should the high-frequency side be configured differently to better reflect the 150–250 kHz band?
4. Are there any best-practice settings (gain, pulse length, frequency limits, etc.) that help optimize performance with this combination of DFF3 + R109LHW?

Any advice from Furuno techs or experienced installers would be greatly appreciated. I want to make sure I’m getting the most out of the hardware before assuming performance limitations are equipment-related.

Thanks in advance.

 

[SilverKing]

FV-PACO,

This sounds like a very good system. Of the electronics you have, TZTL15F, DFF3, DFF3D, none of those will support a chirp transducer. That is why the R109LHW is not listed, This is also why it is manually set-up as a fixed 50/200. Although the transducer will not be using the chirp feature, it will still function the way it is set-up. The great thing with have the DFF3 is that it is tunable. You can really dial it in for the depth you are fishing. On the low end, lower for deeper sounding and higher for shallower water. You typically want to be at the highest frequency possible and still hit the target for the best resolution.

If you want to upgrade anything on the boat, I would recommend it be the TZTL15F, go with one of the new XL series [TZT16X]. These have a built in chirp fishfinder.

 

[Sparky Wire]

DFF3 with a CHIRP transducer shows that the previous owner knew that you can adjust the freq to the depths you are fishing. In many ways this is the best of both worlds and better than using a CHIRP sounder that wastes time sweeping just to find the sweet spot that you can hit every ping with a combo like you have. Great setup. If the transducer is in good location getting clear water, then I wouldn't change anything on the fishfinder side of things. Very nice setup.

 

[Johnny Electron]

It sounds like the previous guy was using 38kHz:38BL-15HR setting just so he didn't need to change the freq to 38Khz himself in the settings. It isn't a problem selecting the wrong transducer on that model because the power/impedance matching is done by the tap settings internal in the sounder. The model number selection would just be moving the freq (in this case 38khz). The R109 is rated from 38 to 75 on that LF side. 38 is good for going deep but the resolution wouldn't be the best for more shallow. For cases of more shallow the LF side can be raised up to 75 to help with target resolution. It all depends on the type of fishing being done and fish being targeted that day. Very nice system.