Topic: towfish cable

[TXPSD]

I see a lot of posts regarding cat cable..

sorry for the duplication and my newbie ignorance...

I just built my towfish and have the standard 30ft cable on a thruhull ducer. How do I splice a new cable in to increase length? what cable should I get?

I need to plug into an 1198si

[Rüdiger]

Hi TX

Up to 110m have already been tried. To splice the cables you'll find several of postshere in the forum, some with pictures.

mvh
Rüdiger

[Rickard]

Hi,
As Rüdiger writes, there are alot of info in the forum on different solutions with extended cables. Here are some general advice. Most people simply cut the transducer cable and splice in an ethernet cable (Cat-level is not important) between the halves. The transducer cable has twisted pairs for the SI channels, so solder these pairs to twisted pairs in the ethernet cable. Just follow the same scheme for wire to wire at the transducer end when you repeat the soldering process at the unit/connector end. The other wires (downward channel, temperature) can be connected to any free wire in the ethernet cable. There will be unused wires in the ethernet cable and they can be left unused or used for doubling the downward channel or as extra ground. The ethernet cable may have stranded or solid wires. Solid wires give less attenuation and patch is more flexible. The ethernet cable MUST be very well shielded and most important the pairs with the SI channels must have individual shields. Be sure the outer shield in the ethernet cable (foil or mesh) and the drain wire (a bare wire) in the transducer cable are well connected. Mesh shield and drain wire use to be very hard to solder so you may have to twist them together and apply some pressure to keep them close (firmly applied tape may do). And then the whole thing must be well protected from water.... Swamp the splice with hot melt glue, cover with lots of tape for underwater installations. One more thing, you need a steel wire or stiff rope to offload the transducer cable while operating the towfish. Start scanning.
 
Regards,
Rickard
 
 

[DiveExplorer]

Some help and info regarding Cat 7 cable.

Where have you bought yours ? I´m interesting of making LowBird unit, and I was thinking of using Cat 7a S-FTP cable. But it seems not easy to find it, at least It is not available where I live so I have order it from abroad, either Europe or US. If there is another, cheaper cable that would do the work I would glad to hear recommendations. I was thinking of making the towfish cable 50 or 60 meter.

Regards, Arne

[Rüdiger]

Hi Arne

Here are a few links to appropriate cables:
http://www.universalnetworks.co.uk/product.htm?product=External-Grade-Steel-Wire-Armoured-Shielded-Cat6-Cable
http://www.seascape.nl/products/video-systems/cables-and-reels/novasub-dlr3
http://www.deluxecable.de/netzwerk-twisted-pair/patchkabel-netzwerkkabel/patchkabel-100m/daetwyler-uninet-7702-flex-frnc-patchkabel-100m-cat-7-1200mhz/a-1015057/

Otherwise google under Network Cable by the meter.

mvh
Rüdiger

[DiveExplorer]

Thank you for those links Rüdiger, but they did not work for me..     

Yes I have google and search the internet. I was looking into those who has some experiences into buying those cables, before I make the decision to buy them. Like if someone has good experiences with some cable company or cable guy...   

[abraquelebout]

hi
ok, next towfish work with Cat 7 a sftp cable,
i join the link of internet shop who send me the cable, no problem and good result with this cable
http://www.destockable.fr/index.php/cable/ethernet/categorie-7-et-7a

[alex]

The complete file for the construction of a towfish
http://plongees-epaves.com/index.php/bricolage-plongee/8-towfish

[Rüdiger]

Hi Alex

So much better can not be this towfish that you should pay money for the plans.
Here in this forum you can get all the info for free, plus good answers to all questions.

mvh
Rüdiger

[abraquelebout]

hi alex
i agree with Rudiger
all people who work in towfish construction done this for free since 2009, whe can find in this forum all to construct a towfish, no money is needed

[alex]

may be, but on the other hand I have already invested over $ of 1,200 in developing and my plan are complete with all the odds, the list of equipment, construction steps.
On the other hand there six months ago I had put them for free on the site and I had found on another site  ???without permission copy

[RGecy]

Alex,

No problem with you posting a link to your plans, but we are also trying to help him out here.  I am sure you have some information that you could share!   And maybe based on your information he will purchase your plans.   

Robert

[Nicolus]

Hi all,
I'm on the way to built my first towfish, and I need to buy the cable.
I've read lots of your useful posts, but I've still some questions about Ethernet cable to use. I will probably buy 80 meters of CAT7a SFTP cable, but :
- Do I need to buy "outdoor" reinforced cable, or "classic" cable is OK and waterproof ?
- Rickard said that Ethernet with "solid" wires is better for attenuation, but there is no risk to break wire when handle or store the cable ? Because it's not easy to find "patch" cable in CAT7a in great length.

Thanks in advance for your help !

Regards,

[Rickard]

Hi Nicolus,

No ethernet cable is really perfect for use with a towfish. We use them mostly because they are available and not too expensive. I have only tested with "indoor" patch cables and they are good up to at least 50 m. The outer protection layer can get leaks easily which means the cable gets useless quickly. My cables have lasted for about 2 - 3 years before leaks have ruined them. I think that cost is reasonable. I have no idea how much longer an "outdoor" cable will last. They use to be filled with some substance that makes it hard for water to get in in case there is a leak. The outdoor cables never come with stranded wires (they use to be "solid") so I expect they are extra stiff and hard to handle. I don't think solid wires is a problem. Some people here use them and when I handle my patch cable I use to collect the cable in wide loops which means there are no sharp bends and no need for stranded wires inside. I still have some spare cable, but I will go for a solid cable next time I have to buy one. Note, the CAT rating is not important in this case.

Rickard

[Nicolus]

Hi Rickard,

Thanks for these information !
About CAT rating, from what I understand, higher category is certified for higher signal frequency. For exemple Cat7 is certified for 600Mhz signal, and Cat7A is certified for 1000Mhz (with side imaging using 800Mhz).
But of course we talk about official certification, nothing says that lower Category cable not support such frequencies ...

Regards,

[Rickard]

Hi,

Yes, the higher ratings means higher frequency rating. But these frequencies are about 1000 times higher than the sonar signals.

Rickard