Old transducer with new depth sounder?

[Bazwat]

So prob a ridiculous question. I have an Endeavour 32 (1980), Australian version, for which I can't find any specs. It has an old Seafarer 3 Depth Sounder. It still works, but is located on the side of the head (where I can't see it), is bulky, LED, and I need an upgrade. The transducer is 150khz. NASA products are also 150khz. I can't get the boat up to change out the transducer, so I wondered if I can use the old transducer with a modern product. Any ideas?

 

[dlochner]

Probably not. Most, if not all of today's electronics use NMEA 2000 and NMEA 0183 protocols. Someone might be producing a device to interface the 150hz signal with a a NMEA protocol.

 

[dirt rd]

You sure can.

 

[dirt rd]

Airmar depth is 2 wire . I connected old transducer to new ray marine I-67/70 instrument . Just wired it to old sea talk connector. Easy

 

[Deparlocean]

I would try to connect the tranducer to the new instrument if it has the same number of wires to connect.
Usually there is two or three, one of them being maybe for the temperature signal.
I do not think it could harm the instrument since there is no source of power from the tranducer. The tranducer being a coil in which a small magnet on the turning wheel indice a small voltage in the coil.
So conclusion: I would try connect and see what happen! Good day

 

[dlochner]

There is a world of difference between the transducers built in the 80s and those available for the past 20 years. In the 80s the transducer was a single purpose device that was essentially a microphone. It was connected to the display unit by a coaxial cable, not the multi-wire cables we now use. The signal was generated by the control head and transmitted through the cable to the transducer, which sent a ping and listened for the return and sent that signal back. The control head then interpreted the signal delay and reported depth.

Today the sensor most of the electronics are contained in the transducer and only the data is sent to the display via a network cable that is also carrying other data.

I learned the hard way when I accidentally cut the cable of an old school depth sounder.

 

[Deparlocean]

That sounds right. I think I misleaded myself thinking more of a speed sensor than depth sounder. But you are right, connecting the old depth tranducer to the new sounder will not work.

 

[jssailem]

As stated. Depth is an analog 2 wire transmission to a decoder. If you want to share the signal beyond a display, you need to convert the signal into a protocol (language) understandable by the displays (NMEA 0183 or 2000).

I took a transponder signal from a 1974 vintage transponder, and attached it to the Raymarine ITC5 unit. It permits a transponder to be converted into NMEA protocol data signal and puts in on the SeatalkNG wires to be displayed on a connected monitor.

Check the display you want to see how it needs the signal. You may get lucky and be able to connect the wires from the transponder directly to the display.

 

[dlochner]

That sounds right. I think I misleaded myself thinking more of a speed sensor than depth sounder. But you are right, connecting the old depth tranducer to the new sounder will not work.

Speed transducers are basically small generators, the faster the boat goes the more voltage it produces. The display is essentially a volt meter.