Seeking 200kHz "analogue" depth transducer

[Lomax]

I've got this old VDO Logic depth sounder instrument which I'd like to fit. Although it came with a transducer and through-hull fittings (it's a removable type), the through-hull sleeve is chipped and looks a little iffy. It also has a wider diameter than the existing depth transducer hole (53mm vs. 42mm IIRC), so I'm thinking perhaps the best (and easiest) route is to replace it with a new transducer which fits the existing hole, but I'm having trouble locating a suitable unit. Everything seems to be NMEA2000 (or some proprietary interface) these days - what I need is a simple "analogue" transducer operating at 200kHz with a single coax connector. Any ideas?

 

[rogerthebodger]

Have a look at this AIRMAR transducer compatibility chart.

http://www.airmar.com/xref.html

 

[Ian_Edwards]

Try looking for an Airmar P7 it's a through Hull 200kHz transducer, I think that it also has a temperature sensor built in, but you don't have to use that.

You could also look for Airmar B17D, which I think is the same basic transducer, but removable, and might require a slightly larger hole.

http://www.airmar.com/productinfo.html?category=MT&name=Marine Transducers

 

[jwilson]

I'm not sure any transducers are specifically "analogue" or "digital". It's just a device that outputs sound, like a loudspeaker but at too high a frequency for us humans to hear. Some will though be tuned to a specific frequency, though will probably work though not nearly as well at others. Some will have extra connections and sensors such as thermistors for seawater temperature, obviously involving extra wires in the cable.

 

[rgarside]

I'm not sure any transducers are specifically "analogue" or "digital". It's just a device that outputs sound, like a loudspeaker but at too high a frequency for us humans to hear. Some will though be tuned to a specific frequency, though will probably work though not nearly as well at others. Some will have extra connections and sensors such as thermistors for seawater temperature, obviously involving extra wires in the cable.

Some transducers have the digital depth finding circuitry integrated into them, and then broadcast the answer over NMEA 2000, NMEA 0183, etc - so they are "digital". Some, like the Airmar P7, P79, etc are just the acoustic transducer and are connected to an instrument that does the digital processing.

 

[Lomax]

Thanks everyone - I just picked up a NOS Airmar P17 200kHz transducer with through-hull sleeve for £30 delivered. It even has the correct (phono) plug on the cable, and the included P617V through-hull sleeve is compatible with their "modern" transducers, which will make any future upgrade a doddle. Another benefit over the 53mm VDO through-hull is that I won't be left with a hole that is (a little) too large for other brands (i.e. Airmar) which seem to use 51mm (2") as standard. The sale didn't include a blanking plug but these are readily available for another ~£30.



Does anyone know what "BG" in the model name means here?

 

[lw395]

I'd suggest testing it before fitting it to the boat.
These things operate as a tuned circuit and one Airmar part number may not interchange happily with another.
Airmar list lots of variants of the P17.
Differences may be as simple as cable length.
They do generally advise not shortening or lengthening the cable.
Or there may be different tuning components in the housing to suit the electronics of different instruments.

Highly likely it's OK, but if it was mine, I'd be testing it before launching the boat.

 

[rogerthebodger]

I'd suggest testing it before fitting it to the boat.
These things operate as a tuned circuit and one Airmar part number may not interchange happily with another.
Airmar list lots of variants of the P17.
Differences may be as simple as cable length.
They do generally advise not shortening or lengthening the cable.
Or there may be different tuning components in the housing to suit the electronics of different instruments.

Highly likely it's OK, but if it was mine, I'd be testing it before launching the boat.

I did post in #2 the AIRMAR compatibility chart that may help in ensuring the purchased sounder matches the OP instrument.