Sonar Transducer Cables - Warning

[James D.]

Got back from Bassmaster University a couple weeks ago and meant to post this msg but almost forgot. One of the Pro's giving the sessions was Don Iovino. He is sponsered by Lowrance and his sessions involved finesse fishing and sonar electronics. I think deep water fishing was his thing. Anyways, the info I got regarded the transducer cable installation on the trolling motor shaft. What I was told was that if you use tye wraps (or anything else) that tightens up against the insulation enought to leave an impression is toooooo much. you've damaged your transducer calbe and affected its sensitivity. I think the jist of it was that the shield inside the cable gets too close to the signal wire or touches the drain wire. His advice is to install with electrical tape or something else that would not smash the outer insulator (the black outer covering of the cable). I found some clips at Academy Sporting Goods that look like they would work out. Thought I would pass this along. We pay hundreds of dollars for all those pixels and then screw up our cables with tye wraps. He also said that you really couldn't tell if the unit was affected or not, but, just go by the insulator, if it is put on tight enough to leave an impression, it is too tight and you need a new cable. Thought I would pass it on.



jd

 

[Mark Hofman]

Use some rubber tape from 3M called "mastic tape". As you wrap it (following the directions), there is a chemical reaction that binds the tape to itself. Eventually, it will harden. I'll try to snap some pictures and post them for folks to see. The stuff is awesome for this kind of an application.

 

[TOMMY RICH]

Interesting info....I have my plastic ties on mine pretty snug. Thanks alot....now I gotta' replace my cable. Seriously that's good stuff. I have not had any problems yet but, maybe later on I could. I'll buy another cable and keep it in the boat....just in case and tape it.

TEE

 

[Staci Matheis]

MO - Where do you get the stuff?

 

[Thomas Macaluso]

Northern Bass Supply sells clips for just that purpose.

 

[Rob LaMoy]

I usually use elec tape anyway. That way in a pinch in the boat you can pull it off quickly without tools.

 

[Andrew Zuber]

OK...

So what do you do if your Dealer installed your unit and used tie wraps? Very tight tie wraps!



James D-

Did the Pro give any symptoms to look for if the cable was crimped too tight???



az

 

[Mark Hofman]

Scott:



I think you can get the stuff at most hardware stores or an electrical supply company. At Home Depot it's about $9 for a ten-foot strip.



Its designed for water-tight applications. When you open the box, the tape is backed with with wax paper. The tape itself is thick, like rubber, with a modest adhesive on the back.



You cut a strip of the tape to length, usually two or three inches. Then, you stretch it to activate the bonding chemicals. A two-inch piece will stretch out to four or five inches. Then you just wrap whatever you need to wrap, just like you would with any other tape.



In a couple of hours, the overlaps of tape will begin to mold together. After a couple of weeks, it's pretty much just one solid glob of hardened rubber. Because of its width, and the fact that you can wrap it even wider, its ideal for securing a transducer cable to the trolling motor shaft.



I didn't use it to secure the transducer cable to the control cables on the trolling motor because I'm not sure in the sheathing on the TM cable would melt from the chemicals in the mastic tape. For that we used tie-wraps, but not pulled so tight that they crimp the transducer cable.

 

[Bob G.]

Andy,



I would cut the tie-wraps off and use tape. I think mine was installed with electrical tape and I wondered why. Now I know! I guess the tech knew what he was doing.



Bob G.

 

[James D.]

Andy,



he basically said the unit would appear to work fine and you might not notice anything. the way that you can tell is to take off a tye wrap and see if there is a deep impression in the cable or 'memory' of where the tyewrap was. I think it affects the sensititity and may cut down on the amount of detail that you would see. I had the understanding that the cable DID NOT have to be cut, but just smashed to affect the performance. Sounds like a real bummer as I know that a lot of these are installed this way (that is how I would have done it too). If you think about it, that units is sending and receiving signals very quickly many times a second and is trying to differentiate between very minnute changes in signal. If the "attennae or transducer" is not letting all of the true signal thru, i could see not all the info being displayed. the old addage "garbage in, garbage out". I will email Iovino and see if he would maybe add to this and maybe put up a post on our site. might also email lowrance or garmin or humminbird and see what they say also.



jd

 

[James D.]

mofish,



thanks for the post on the tape as that does look like awesome stuff. should have a lot of other applications also.



jd

 

[Paul Jones]

Guys,

You are making this WAY TOO hard. The cable from the transducer is a thin piece of coax similar but smaller than what is used on a cable TV. It a piece of copper wire surrond by plastic insulation. You cannot "squeeze" it like a water hose and effect it's operation. The only way you can change it operation is to break the insulation and that would cause you to have constant erratic operation, or break the internal wire and this will cause it to not work at all. Squeezing the wire with a zip tie on anything else will have no effect unless it does one of the above things. This is electronics 101. I know we idolize the fishing pro's but the initial comments have no basis in fact.

 

[Mark Hofman]

My biggest concern about using tie wraps on the transducer cable is that the sheathing could be pinched in such a way that it would eventually tear (or be cut) and would allow water to seep inside the insulation. That's why we went with the mastic-tape approach.

 

[Staci Matheis]

Thanks, Pauleye! That was kinda my first reaction - but what the heck, I don't know coaxial from triaxle! I do like MOFish's tape suggestion!

 

[John Foster2]

I have to agree with pauleye on this one.

 

[Larry Harp]

I was at the same B.U. and my interpertation was the over tightened zip tie would crush the woven wire shielding between the plastic insulation and the little copper wire running through the middle allowing outside interferance to enter the signal thus causing static and false readings.

I certianly DO NOT idolize Don Iovino. In fact I had never heard of him until that day and thought his presentation on finesse fishing and drop shotting was the weakest part of the show. However, I do have a class I FCC license and I understood what he was saying about electronics and thought he was very credable. He is really kind of a no BS kind of guy and I don't think he would give us this information without a basis of fact.

I personally, am going to take his advice.

Harpo

 

[Bruce Freeman]

Scott The triaxel has 3 sets of rear wheels...LOL

BF

 

[James D.]

Pauleye,



i respectfully 100% disagree with you. If you think that all coaxial cables are the same, i think you are way wrong. If it is your thought that just because the wire is not broken that it is still making the 'circuit' and that the signal is not affected - i think you are way wrong. maybe that works for passing current and dc circuits and turning on light bulbs, but the game changes when frequencies and signal strength is involved - you know 'electronics 101'. with the speed and sensitivity of the signal to be measured, everything matters. maybe not enough to you, but maybe to someone else. I think each should evaluate his own cable and installation and what his sonar returns are.



disagree if you like, no big deal to me. I do not 'idolize' anybody walking on this earth as we are only here for a short time anyways, so you can take me out of that category. I don't think that your post has much merit or basis in fact other than your own understanding. i mean, go ahead, cinche them cables up real, real, real, tight! what do I care. enjoy.



jd

 

[James D.]

ya know,



what I love about this site is folks like MoFish. He doesn't say something does or don't have merit, he just jumps right in and comes up with a good solution. always posts good pics and helps out. I think he kindof likes fixin stuff.



jd

 

[Anotherdink Scott Chambers]

Okay, how you get the bad signals with a pinched coax/triax is interferance (like your trolling motor uses a electic motor it generates a frequency eg) with any damage to the sheilding that frequency comes in as a false signal (your cable acts like a antanea ) but is percieved as a signal by the a/d processer in the dispaly unit. We use to get cables in that where barely pinched out of the aircraft (especially triax) that looked undamaged but would cause birds (false signals/targets) on the radar dispaly. So yes I can see his point but mine has tie wraps on it because I just never thought about it but I will not use them with my new garmin I bought (sometimes you just need to be reminded about what ya already know, Thanks). About the 3m tape we use to call it f4 tape because that and bubble gum is what held the old F-4's together it is great, I had never actually seen it for sale but I will look for it at h/d or lowes.

 

[Bill McElroy]

I've been using zip ties for years and have NEVER had a problem,....you don't have to install them so dang tight that they squeeze or cut the cable,.....just zippem' down tight enough to hold it in place and then cut the tag end off....it's not going to damage the cable!! IMHO!!

Mac

 

[Staci Matheis]

MOFish likes BREAKIN' stuff!

That's why he has to know how to fix it.....

.....before his Mama finds out!

 

[TOMMY RICH]

I,ve never had any problem with my EagleIII that's been on three baots with and LCR at the console and it's never failed. I compare what both LCR's are saying and they are dead on. Now mind you I don't squeeze the crap out of em' either...just enough to hold the wire in place.

TEE

 

[Paul Jones]

Boy we all are sensative. My point on "idol" is just because someone use a piece of a equipment does not make them an expert on the way it operates technically



Here's the deal a piece of copper is a piece of copper it will flow current a the speed of light. The limitation is the thickness of the wire and the amount of current. The thinner the wire the less it will flow. Ergo that why thin wire is used in some fuses.



The things that cause trouble are the connection at either end, a break in the wire, or in the case of coax a problem with the ground continuity from end to end of the shield surrounding the core wire or in triaxal wire.



My point is if you sqeeze a wire you cannot effect it in the way you squeeze a water hose. That is IMPOSSIBLE. You can cause permanent damage in any of the ways mentioned in the paragraph above.



My expertise: I started fixing Naval electronics on an aircraft carrier in the Gulf of Tonkin (Vietman) in 1968. By the way, the sonar (fishfinder)used today is not a lot different than than they taught me in electronics school in the navy in 1964 that are used on war ships. It's the displays and enterprative electronics that are more complicated not the delivery of the sound wave through the water.

 

[James D.]

spoke with Don Iovino today on the phone and discussed this further. He laughed, and said this is somewhat the reaction he gets also. He told me it would be ok to post his website address where we could email him with any questions, and that he answers his emails personnally. I think Don's a really nice guy. He mentioned that Lowrance did some tests and that it (the squeezed cables) causes a db loss in signal and makes it susceptible to interference. His website address is http:/www.Iovino.com . I also have a EET degree in electronics.



jd

 

[Mark Hofman]

Scott:



You joke, but you should've seen the look on my wife's face when she came upstairs and saw me on the kitchen floor with the dishwasher torn apart. She didn't say anything, but I could tell she had concerns about whether it would ever work again - or if a qualified repairman could figure out how to fix what I had undone!



(All I would have had to do was call her brother or her father and things would have been fine. But I fixed it myself.)

 

[Larry Harp]

Paul,

I don't think James or I are trying to cop and attitude here but your referance to squeezing the wire to slow down the electrons like water in a water hose is almost insulting. That would require a resistor-- a concept I learned in 8th grade electronics class when I soldered the Heathkit radio together.

The point I think your missing is the zip tie is damaging the outer sheild and allowing outside RF from everything from the trolling motor to the wiring to the trim switch. Don also cautioned against wiring to the TM battery and routing the transducer cable too close to other power lines. It's only a precaution, not the 11th commandment. You may go around with damaged wire for the rest of time and never even realize it or you could take simple little step that cost nothing when you install your next TM and get a lot better performance out of your investment.

I appreciate James trying to help other members of the site with this simple tip.

Harpo