2nd Depth Finder

[larman]

So my very old Lowrance 3400 depth finder does not work. One of my winter project was to find out where the transducer is and hopefully install a new depth finder. My primary depth finder is in my Garmin chart plotter. Is it possible that I am sharing the transducer with the Garmin transducer? The wires from the lowrance connect to this box. Is this some kind of nema backbone?

 

[Juliet 15]

I don't believe it's possible to share a transducer. I could be wrong, but I tried it with a Furuno and a Garmin. No go. Not sure that would have even given me the redundancy I was looking for anyway.

 

[alfamike]

Dual Depth sounder advice

If you decide to put two depth soundres, two ways to go.

!. - separate them with as much distance as you can.

2. - have them be types that operate on different frequencies.

The three most common are as follows

200 Hz - most accurate in shallow water.

120 Hr - a compromise between the 200 Hz & 50 Hz. -

50 Hz - best to go to the deepest depths.

So by not using the same frequency, you don't get any interference in one signal throwing the other off accuracy wise.

Good Luck.

Alfa Mike

 

[larman]

Do you know what that box is in the pic?

 

[JDCAVE]

If you decide to put two depth soundres, two ways to go.



!. - separate them with as much distance as you can.



2. - have them be types that operate on different frequencies.



The three most common are as follows



200 Hz - most accurate in shallow water.



120 Hr - a compromise between the 200 Hz & 50 Hz. -



50 Hz - best to go to the deepest depths.



So by not using the same frequency, you don't get any interference in one signal throwing the other off accuracy wise.



Good Luck.



Alfa Mike

Yes, but separation of the two transducers on the boat does little to solve the problem of “cross talk”. You MUST operate them on separate frequencies otherwise the issue remains.

 

[Nomad Willy]

I have a Garmin fish finder and a digital Ray Marine high end dedicated sounder.
I’ve had two sounders for as long as I can remember and use their differences extensively to our benefit.

 

[C lectric]

Not an electronics guy or a sounder guy

but open the box and take a look. Look to see if the wires are spliced, likely.

It MAY be possible to share IF the transducer used on each device was the same T.D. which may have been the case. Airmar makes most of the T.D. for all sounder mfgrs. so maybe. If not and this was truly cobbled then neither unit may have worked as well as they should have been able to.

You might also ask Airmar but you will have to determine which T.D. is used. THere is often a label/tag on or near the T.D.

I personally would not do it regardless. IF the T.D fails and they do then you have lost all function. Also I would THINK that if both units were operating at the same time they could damage the T.D. OR damage one or the other units. A lot of electronics cannot handle backfeeds of this nature.

Maybe one of the electronics guys will weigh in.

 

[Shrew]

So my very old Lowrance 3400 depth finder does not work. One of my winter project was to find out where the transducer is and hopefully install a new depth finder. My primary depth finder is in my Garmin chart plotter. Is it possible that I am sharing the transducer with the Garmin transducer? The wires from the lowrance connect to this box. Is this some kind of nema backbone?

I'm a bit confused, but I think it is because you're interchanging nomenclature.

The Transducer is the sounding device in the hull. The Lowrance is a Display that is more then likely a dedicated device (Depth). The Garmin is a Multifunction Display (MFD) (Chart plotting, Radar, Depth, AIS, etc).

If you have depth on the Lowrance display and the Garmin MFD, then you either have two transducers, or you are sharing a transducer between both displays.

It looks like the signal from the transducer is being split at the box. I have never seen such a device, but that doesn't mean anything.

1) Trace the transducer cable back from the Lowrance display

2) Trace the transducer cable back from the Garmin MFD.

Where do they go? IF they both go to that 'black box' then disconnect the one for the Garmin and see if it still displays depth data. Then repeat for the other connection.

Finally, trace the cable from the black box. If that is for the transducer cable, you will eventually find it somewhere in the hull.

 

[jgwinks]

If you want to have two depth finders running at the same time (why?) then they have to be on different frequencies. If you're talking about putting one at each helm, then only turn on the one you're actually using. If the other ones off, no problem.

 

[sunchaser]

If you want to have two depth finders running at the same time (why?) then they have to be on different frequencies. If you're talking about putting one at each helm, then only turn on the one you're actually using. If the other ones off, no problem.

I've got 3 operating units. They are in good agreement until water depth above 300' then the Furuno DFFI wins.

 

[psneeld]

2 MFD's can just share NEMA info with just one getting info from a transducer.

 

[Nomad Willy]

If you want to have two depth finders running at the same time (why?) then they have to be on different frequencies. If you're talking about putting one at each helm, then only turn on the one you're actually using. If the other ones off, no problem.

For me the display is way different and better or worse in various ways. Sometimes I needed bottom info like rocks, sunken trees ect and other times I need accuracy .. or a good reading in deep water. Sometimes I need a number that is easily recognizable w just a flash of eye contact. Ect ect

Yes jgwinks they are on diff frequencies ... and on different sides of the bottom.

 

[Satch]

Take the box off and look for a nameplate, label, sticker, etc. I only see one screw holding it down and it looks like easy access. If you find some markings that will help us identify it, take a photo and post it. If it has no markings, it's likely homemade. In that case, open it up, take a photo of the contents, and post that.

 

[FlyWright]

I added a Hawkeye 2" depth sounder for about $100 to compliment my Furuno fishfinder data. I epoxied it into the hull and have had no problems. I have a solid FRP hull (no core). The website specifies suitable hull types and thicknesses.

https://hawkeyeelectronics.com/collections/boat-mount/products/depthtrax-2b-boatmount-depth-finder