Can I cut my depth tranducer cable?

[yerffoeg]

Your advice please.

I am fitting a Navman depth transducer. In the instructions it says do not cut the cable. The problem I have is that the plug/socket on the other end of the transducer will not go through the cable route that I have planned. Making holes in various bulkeads etc big enough for the socket will cause major grief. If I cut the cable everything then becomes simple, as should be re- joining up the cable.

Is there a serious problem in cutting and splicing such a cable in terms of signal loss / interference etc?

 

[poter]

Re: Can I cut my depth transducer cable?

nope! just done the same.
Are you mounting the transducer inside the boat or on the transom?
If inside I would strongly suggest that before you cut anything you try out the transducer in position, to make sure it works & save yourself all the trouble of re-routing the cable.

good luck

poter

 

[William_H]

Re: Can I cut my depth transducer cable?

As I understand it, it is more critical that you do not shorten the cable for depth sounder transducer. The cable is part of the timing which determines accuracy and the capacitance of the cable is part of the tuning of the circuits.
So do not shorten the cable. If you can disconnect at the plug and reconnect in the same way that would be safest other wise cut anywhere and use a coax connector or solder the wires together with as little disruption as possible. Pay attention to sealing the joint agianst moisture ingress. good lcuk olewill

 

[Guest]

The book is of course correct .... length and impedance of the cable is part of the calculation for depth.

But in practical terms .. cutting the cable as CLOSE hard up to the plug as possible .. OR if you can "pull" the plug of to have only cable - then feed through your bulkheads etc. - then fitting a new plug on the end shouldn't throw that length or impedance out enough to make any difference .. IMHO Just make sure length is as close to original as possible and also plug is fitted well. I would avoid cutting and joining anywhere else - as you are asking for joint trouble later ... which will likely drive you nuts diagnosing !!

 

[simonfraser]

cut it, solder it back together again, no prob, have done this several times

 

[Stemar]

My sounder fits in a removable instrument pod. I had to cut the cable to fit it. It's now connected by a standard computer netwok plug (BNF?) which gets unplugged along with the log sender and GPS antenna every time we leave the boat. It works fine.

The important(ish) thing is to keep it the same length as it is part of a tuned circuit, but I'm not even sure how important that is, really. After all, the speed of the signal in copper wire is about 1/10th the speed of light, so maybe 670,000,000mph, the speed of the sound pulse in water is roughly 700mph. A few inches or feet less cable is hardly going to matter on that basis.

Pehaps the electronics engineers here could explain the fault in my logic. I'm genuinely curious to know if there is one

 

[fluffc]

[ QUOTE ]
it is part of a tuned circuit

[/ QUOTE ]

I fail to believe that an engineer would be so cack-handed in their design that the length of cable had an effect on the ability to transmit and receive frequencies only slightly higher than the human ear can detect.

After all, do we worry about the length (or makeup) of audio interconnects and microphone cables???? The reason that coax-type cable is invariably used is for ease of construction; nothing to do with the ability it has to carry an ultrasound blip.

I now await a comprehensive dressing down by an engineer who designs these units...

 

[yerffoeg]

Thanks for some excellent replies. I have gone ahead and cut the cable! I will not change the length.
It did occur to me that even if the signal is affected by shortening the cable, could not the transducer be recalibrated accordingly? Anyway, I do not intend to shorten it.
Thanks again.

 

[Guest]

[ QUOTE ]
Thanks for some excellent replies. I have gone ahead and cut the cable! I will not change the length.
It did occur to me that even if the signal is affected by shortening the cable, could not the transducer be recalibrated accordingly? Anyway, I do not intend to shorten it.
Thanks again.

[/ QUOTE ]

I would assume using keel offset would be enough to take up any change ?

But as many have found - the change in length as long as kept minimum has olittle effect on readings ..

Let's be honest ... wave action / boat movement will have far greater effect on displayed depth ... so a cm here or there ??