Other Interest > DIY - Side Scan Sonar and towfish

is a 200m Cat7a cable possible?


Hi all,

I think that the typical limitation of Cat 7a cable without some sort of booster is around 100m. I own a Onix 10ci SI and I am trying to build a towfish to side scan in lake/ocean with depth between 200m and 250m. The aim is to locate shipwrecks.

I was wondering if any of you had tried a 200m or 300m cable and what kind of attenuation on signals/noise was present?  Was is usable?


Hi babafeit

Welcome to the forum

Nothing is known to me over 100m, you have to try that yourself. However, you should also seal the cable entry on the transducer when used at such a great depth, there have already been problems. You should also consider the tensile load with such a large cable length.
Please continue to report on your project here.


It should be possible with the correct cable. Not sure if CAT7A is it or not but on this site https://www.edimax.com/landing/long_range_poe_solutions/en/ it does show a PoE range of 100m extended out to 200m. I'm thinking that is just from voltage drop. I'm guessing that is going to the same problem with the transducer cable. There are other ways to prevent voltage drop. You could use a cable that has a heavier gauge wire. I would test it on an extension cable before destroying your transducer cable.

Hi Chris

With very long cables, the ohmic resistance and the associated voltage loss become a problem.
But maybe you will find something here:




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