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Reconnecting cut transducer cable on Standard Horizon DS35

Dec 1, 2020
86
CAL 27 Illahee / Brownsville WA
Due to my stupidity I cut the cable between the display unit and the transducer. Can I simply reconnect the wires using marine grade crimp and heat seal connectors or flux and solder and then wrap, or do these cables need to be replaced when stupidity rules?

The DS35 is a standard 200hz type frequency I read.
 
Jan 11, 2014
7,746
Sabre 362 113 Fair Haven, NY
Years ago I had the same problem. If I recall correctly, the cable is a shielded cable, if that is correct, then crimp on connectors won't work. I think I tried that.

Is there a connector between the transducer and the cable? Or is it hard wired into the transducer?

Standard Horizon has been out of the marine instrumentation business for about 20 years, so finding any direct replacements will be difficult if not impossible.
 
Mar 6, 2008
681
Catalina 1999 C36 MKII #1787 Coyote Point Marina, CA.
Yes, just solder, use shrinkable tubing. Be sure to connect the bare wire aswell. Make the wires as short as possible. You can wrap with same shield wrapper. Do not fold the wires. No crimp sleeves. You have nothing to loose.
Haro.
 
Sep 25, 2008
434
Catalina 30 MKIII Varuna Boat Club
Several years ago, I was informed by a local Tech that has his own repair business, never to splice transducer cables. Any change in length will alter the impedance and therefore distort the sensitivity of the unit, giving false readings. If its old, replace it. If not, just curse the mistake and move on.
 
Oct 22, 2014
15,863
CAL 35 Cruiser moored EVERETT WA
Making the connection is a low risk adventure. Just be sure to connect A to A and B to B. There are likely just 2 wires. Often there is a central core wire ( Positive) and a shield wire (Negative)

Something like this would work if WaterProofing is important.
1625249906113.png
 
Jan 11, 2014
7,746
Sabre 362 113 Fair Haven, NY
Several years ago, I was informed by a local Tech that has his own repair business, never to splice transducer cables. Any change in length will alter the impedance and therefore distort the sensitivity of the unit, giving false readings. If its old, replace it. If not, just curse the mistake and move on.
:plus:

If the cable is shielded, i.e., has a wire mesh surrounding the inner insulated wire (aka a coaxial cable) splicing it will affect the impedance and the signal transmission. It may be possible to find small coax connectors that would work.
 
May 29, 2018
294
Canel 25 foot Shiogama, japan
Do it and let us know if it works.
Try the easy (crimp) fix first and if that doesn't do it, go for solder.
Don't forget to report back.

As @JoeWhite said, Nothing to lose.

gary
 

DArcy

.
Feb 11, 2017
1,200
Islander Freeport 36 Ottawa
At 200Hz it's not too hard to create a passible splice. There are two types of losses you need to worry about with higher frequency connections: insertion loss, and reflection loss. Insertion loss might come from long cables or cables not capable of handling the power. Reflection loss comes from impedance miss-match. Any change in impedance causes some portion of the transmitted power to be reflected back where it came from.

The power of the depth transducer is probably fairly small so not much concern with insertion loss as long as you make good connections and don't use too small wires. Reflection loss can be more challenging but at this low frequency you should just try to maintain a constant shield diameter. Pull the outer shield back. Strip back and solder the center conductors but cut back the dielectric as little as possible (the material between the center conductor and shield). The find something to bridge the gap, maybe wrap with e-tape, to build up to the dielectric OD. Then pull the shield over and solder the two sides together. Finally heatshrink sleeve to close it all up.
 
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Likes: Ken Cross
Feb 8, 2014
1,300
Columbia 36 Muskegon
I've spliced transducer cables when connecting an already installed ducer to a new display head and they didn't use the same plug. Didn't seem to affect the performance at all. In fact the Hawkeye sounders have instructions on connecting them to other maker's ducers, and they don't mention any problems with impedance, etc.
 
Oct 24, 2010
2,391
Hunter 30 Everett, WA
DArch has it right. Absolutely it can be spliced, but use a properly shielded splice.
If you don't know how, do a youtube search. 200 kHz is a pretty easy frequency to deal with.
 
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Ward H

.
Nov 7, 2011
3,093
Catalina 30 Mk II Barnegat, NJ
Airmar makes a waterproof barrel connector for splicing transducer cables. I’ve used them on wind, depth and speed transducer cables with success. Here’s a link.
Splice Connector

I'd expect if a connector like this works other methods suggested would also work.
 
Oct 24, 2010
2,391
Hunter 30 Everett, WA
Airmar makes a waterproof barrel connector for splicing transducer cables. I’ve used them on wind, depth and speed transducer cables with success. Here’s a link.
Splice Connector

I'd expect if a connector like this works other methods suggested would also work.
Yep, other methods definitely work, but then I'm an old electronics tech and lived lots of my life with such things.
For some people, it's black magic. The trick here is to try to maintain the same characteristic impedance. At ultrasonic frequencies it's pretty forgiving, Just don't shorten it more than absolutely necessary to maintain calibration and maintain the shielding.
 
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Likes: jssailem
Dec 1, 2020
86
CAL 27 Illahee / Brownsville WA
I finally got out to the boat and discovered I'm more of an idiot than I already knew. The cable I cut was not the "current" transducer but an old unit. After pulling the connector apart at the DS35 cleaning a bit and re-connecting I get readings "occasionally" that make sense given where I'm at when I see the reading. Most of the time though there is no depth displayed. No changing of the DS35 settings makes any difference.
ds35_cable_connector.JPG


I have followed the "correct" cable from the DS35 to the actual transducer and looked at the Airmar website and they have a vast array of these things.

airmar_transducer.JPG


I'm hoping to figure out what model this so that I can determine if a replacement depth finding gauge has the correct frequency. Since the DS35 operates at 200hz and I occasionally see readings it sound like that may be it, but it would be good to know what the unit actually is.

I will post my question about the model number of this unit to address that in a separate thread.
 
Oct 22, 2014
15,863
CAL 35 Cruiser moored EVERETT WA
You should not need to worry about the frequency. It will impact how deep you can get readings and the width of the area sampled, your system should adapt to the signal.
All you really need is soundings down to 50 feet.

This might help to understand the difference in signals.

Transducer Frequency
Transducer Frequency

Transducers for recreational and light commercial boats usually operate on frequencies between about 25 and 400 KHz, with 50 and 200 KHz being the two most common. As with most radio or radar transmissions, lower frequencies generally have greater penetrating power while higher frequencies offer higher resolution or detail. A low frequency around 50 KHz is excellent for displaying a wide area of the bottom, especially if the water is deep, while a higher frequency shows more bottom detail in shallow water, a very useful trait for fishfinders and recorders. A depth sounder signal that reads up to 400' in fresh water may lose as much as half of its penetrating power in saltwater, so lower frequencies may be favored for saltwater use.
 
Dec 1, 2020
86
CAL 27 Illahee / Brownsville WA
John, I believe transducers are designed for a specific khz and the depth gauge needs to "talk" that frequency for the units to work together. The old DS35 had a setting of 200hz +/- 1 that could be set.

I agree 50 feet is all you really need, but the unit needs to not show a blank screen when I get close to a beach. Sitting on the mooring in 20-25 feet I get no reading.

A new Ratheon i40 is under $200 without the transducer. Not sure how the contrast is for that unit though.
 
Oct 22, 2014
15,863
CAL 35 Cruiser moored EVERETT WA
As a place of reference, my 1974 boat came with 2 transducers. One was in a oil bath attached to the hull the other was a through hull with bottom paint. As the oil bath was attached to a SiTech display from the late 1900's I attached it to the new Raymarine itc-5 analog to seatalkng converter. It fired the transducer right up and started searching for the bottom. It produced a NMEA 2000 equivalent signal that I can see on my iPad as a 200kHz driven signal due to the depth limited reading capability in mucky water. Had it been a 50kHz signal it would have read the same data but with a greater capability to penetrate the mucky water and to deeper depths.

The tuning of the display is not something I have observed. The old units were designed for the 200kHz transducer as I understand. The new displays accommodate both transducer rates as I am informed. The newer units like the 50 kHz for the ability to improve clarity and depth. Low frequency waves travel slower but are better reflected then high frequency waves in water. The high frequency, as I understand, is used in the shallow depths to provide greater contrast. The new Chirp and such displays have computer assist to provide clarity to the display.