LSS-1 side scan

[Stuart]

Hi, new to this forum and a bit of a passionate nut with an LSS-1
Reading breifly over the posts i assume there maybe some advanced users who may have solved the problems of extending a tow fish below 20mtrs...

There are two options, ethier extend the cable to the transducer or extend the cable up from the box (Yes a housing is all ready made, including fish)

The problem is, what cable will work best over what distance given both have pitfalls>>>?
any ideas

cheers Stu

[Rüdiger]

Hi, new to this forum and a bit of a passionate nut with an LSS-1
Reading breifly over the posts i assume there maybe some advanced users who may have solved the problems of extending a tow fish below 20mtrs...

There are two options, ethier extend the cable to the transducer or extend the cable up from the box (Yes a housing is all ready made, including fish)

The problem is, what cable will work best over what distance given both have pitfalls>>>?
any ideas

cheers Stu

Hi Stu

I think Cat.6 or Cat.7 Networkcable can be a good choice up to 60m.

mvh
Rüdiger

[Rickard]

Hello Stuart,

I am a Humminbird user, but considered using Lowrance and the LSS-1 to avoid the attenuation issue with long cable in a towfish application for a while. The good thing with the LSS-1 system is that the transmitter/reciever can be sent down with the transducer, which allows for a short transducer cable and therefore low attenuation. The cost is, of course, the need for a water and pressure tight housing for the transmitter/reciever. I suggest you try with extending the signal cable between the head unit and the LSS-1 box. I think this is a standard ethernet type of cable, but Lowrance offers dedicated extensions. Max cable length in ethernet applications varies, so you should contact Lowrance about that if it's not in the specs.

Regards,
Rickard

PS I have not heard of anyone who has tried this, please tell us how this develops!

[Stuart]

Thanks guys
Alas not quite that simple
Richard, i read your post last night from a few years ago,( I have no issue with the housing) Got all excited that maybe the other problem had been solved....
The transducer to box uses a strand cable core, hence while flexible only has a useable distance of around 10m, (transducer 6m / extension 3m (standard limit) but i added another 1/2m with a switch box, that turns the down scan off or on along with the others... (So my current fish are maxed out, they reduce boat pitch & roll effects on scans, are stabilized for corning scans and one vertically scans, I have overcome scan reflection along with the removal of those annoying bumps, and the down scan is no longer 2/3 backs wards 1/3 upside down any more) (Which really did bug me)
On the other side of a LSS-1 box, the Ethernet is a solid core, can be up to 100m long, however prone to breakage when flexed, so if replaced with a strand cable core..?, am i back to 10mtrs again and that’s the dilemma...
Rule of thumb in Ethernet, strand cable is patch cable limited to roughly 10m... and only a cat5e type i have found as sheathed outdoor cable... (so not looking good)
Ideally i want it as a fish as well... but it will run regardless as a dive unit with a HDS 5 for close survey scans of wrecks down to 100mtrs and caves etc, so there are a few other minor issues like a low cost acoustic positioning system over using a measuring tape to solve....
Cheers Stu

[Rickard]

Stu,

Don't you lose the point with a submerged LSS-1 box if you can't extend the ethernet part of the system? It's true the specs for the various ethernet categories set a 10 m limit to stranded cables, but that's set with a safety margin and the Lowrance system may be much less sensitive than a typical ethernet system. I have used some cheap solid ethernet cables and they are not too difficult to handle, just don't coil it up with too small radius. Sooner or later it will break or leak, but then it's not so expensive to replace it. If you want to get 50 m down, a pretty heavy towfish is needed, more than 10 kg (22 lbs), so the ethernet cable can't take the load. I use a 3 mm steel wire for the towing job and the transducer cable is just attached to the steel wire with tape.

Rickard

[Stuart]

Cool
My Fish are not round, foiled shaped (200mm wide x 30mm high x 800mm long, standard length only needs 2kg ) The intended fish is 1.1m long, internally can carry 16/ 2kg diver weights and the LSS-1 box in a box is 6 & 20mm thick side wall alum plate, 80 x 250 x 400 long, mounts separately under the fish...
A Lowrance Ethernet cable uses only two shielded twisted pairs, while a standard cable has 4, assuming i use a sheathed outdoor cat5E 170N pull strength cable with a 3mm wire tracer...
Can i run power down a single twisted pair + & - 12V ..?
Given a 50m cable, would i have to increase the voltage slightly 14/15V....?
Would the power routing down the cable cause interference to the signal...?
And can i save the last twisted pair for on/ off switching of the transducer array..?
Cheers Stu

[Rickard]

Hi Stu,

That's good, you can make the fish heavy enough. I can't tell if you can feed the box through a twisted pair, that depends on the power consumption in the box and the resistance in the cable. My Humminbird system takes about 1 A, but that includes power for the display. I would consider sending down a small mc-battery with the fish, but of course, increasing the voltage can solve the problem. I don't think those batteries need a housing, so it won't add much complexity to the system. The DC current in the power circuit doesn't affect neighbouring circuits, provided it's reasonably stable. Whatever the solution will be, always use separate batteries for the sonar system! Any direct contact between the boat's electrical system and the sonar will cause interference to some degree. Turn LED lamps and any device that can emit anything off. Even the engine should be turned off.... It should be possible to use a pair for turning the transducer on/off, provided there is no current or voltage peak that interfers with the ethernet communication. Is there no way to control the transducer through the ethernet? Perhaps there is a control option in the head unit?

Rickard

[Stuart]

Hi Mate
I would admit that ever 100mm deeper gets allot harder, and there is a sense of achievement when you do.... So yes you could throw a cable on and drag it across the bottom and get some result without too much trouble... However not really a fair-dinkum result... It’s got to do it with style, with all the bell & whistles and the result should have a wow factor...
Cat5,6,7 and so on relates to how many twists per metre, the more twists the more data transfer... Sadly a sheathed outdoor cable only comes in the low data range and on a roll 100m & 304m (roughly $800 to $2500 a roll) and if i have a separate power cable +wires for transducer switching, then better to house the cables in a 16mm reinforced conduct ($200 per 25m i think)... given the cost might as well consider the use of a standard 6.7mm Kevlar cable $1000 per 50m (but i have no idea if it will work)
So yes at the end of the day i will just have to bite the bullet and set up a cheap test cable... but it is not that cheap to get it wrong...
Definition of a “proper working LSS-1” is not really a standard LSS-1, and i would admit i have no idea how the white man’s magic works inside the box, but i do know, “ALL” consumer depth sounders that scroll from right to left, scroll the wrong way for down scan and all scans that use sounder files types have the same problem...
Objects appear either up-side down or backwards and can be both and a down-scan can plant corrupt over lays to the water fall image.. (This issue is best addressed with images) (So yes without a doubt transducer switching)

Bottom line, it will be sexy, look good doing it, and bring home the bacon, and as an amateur it doesnt hurt the ego to show up the professionals....
Cheers Stu

[bigkahuna]

Can i run power down a single twisted pair + & - 12V ..?
Given a 50m cable, would i have to increase the voltage slightly 14/15V....?

You may find a voltage drop calculator to be helpful in answering this question: http://www.supercircuits.com/resourc...ls/voltageDrop

I'm following this topic with interest as I would like to mount a SS unit on our ROV that has a 250 foot cable. We're looking at using a Humminbird unit at present but the signal loss / voltage drop over such a long distance is sure to become a problem. I'll be interested to see how you overcome this issue with the LSS-1.

[Stuart]

Thanks for that, answers a question, 20V
In regards to your 250mtrs, there is not a chance; the only way would be to convert the signal in the ROV to another type, like a phone line....or, Given an ROV, provided side scan is not its primary function, then ideally on/off and record to a logger, (view the results later) and/or use a camera to view a the depth sounder in the housings....
However if we are talking 250mtrs down (deep).... A transducer/head is a clever device; transmitting sound to water is a tricky thing... While water can’t be compressed, the space in-between water molecules can, and any air space crushed... the LSS-1 turns to liquid mush when on, so more likely at some point on that 250mtrs decent, their little hearts will slow or stop beating....
Given both are designed transom mounts (2ATA) working depth is merely a question of “who got the best depth so far”, and a LSS-1 even at 10mtrs is uncharted territory... (And if some one has better than 6mtrs, i would like to know how)
A Hummingbird i have no idea, but it would be interesting to know...
Cheers Stu

[bigkahuna]

@Stuart - The cable is 250 feet not meters, which is approximately 76 meters in length. Water depth will be 50 feet (15 meters) or less.

Several fellows on the Humminbird forums are using fairly long transducer cable extensions (50 meters or longer), some with good results.

The ROV with side scan would operate much like a remotely operated boat: I would drive the ROV in a grid pattern while watching the side scan monitor. Then pass over targets of interest to get a better side scan image. Once located, the ROV would dive to the bottom to (hopefully) look at the target. Water visibility here is a big problem, thus the necessity for sonar.

[Rickard]

Stu,

The voltage drop in an ethernet cable will be very substantial with these lengths of cables. Somewhere I read the LLS-1 takes between 0.5 and 1.0 A. Almost all the 12 V will be lost. I still think the submerged mc-battery is a good idea. Just get a cheap sealed battery and send it down to 50 m and check if it survives. Same thing with the LSS-1 transducer, send it down and check what happens. I have tested the Humminbird SI transducers at such depths and they seem unaffected. The only compressible substance inside a Humminbird transducer are thin (about 1 mm) layers with cork around the piezos, the rest is massive epoxy. I guess that, but don't really know, the LSS-1 have about the same properties.

Rickard

[Stuart]

Richard your right, but there always going to be a “however”.... certainly the dive extension (HDS-5 add on) will have an external 18V Lo-ion Battery...

The LSS-1 box in a box ideally will not, and while it will have a wet connector to power it, it is more about keeping the size down, drag and associated problems out of the box...

A single human hair across an O ring has seen many a flooded camera or dive unit, they go BOOM, add a battery you can get a far more spectacular BANG for your buck.... A sealed lead acid battery gives off hydrogen while discharging; (can go boom) a minor flood may cause a rapid discharge (Will go boom)... certainly i know of DPV blowing the back windows out of a car, the worst case while friends travelling home, a DPV on the roof rack, the hydrogen ignited (No one’s how it did it) the result was burning the 4WD & trailer to the rims with all their gear....

1) Not a wise to seal batteries in a container next to electronics if you can avoid it...
2) Sealed lead acid Batteries, just means it won’t spill, they are not water tight or can you make them, there is a hydrogen gas discharge with vents in the battery...(look closely on the top)

Regardless how it happens, the common issue, any leak will pressurise the container at depth, the greater the depth the higher the pressure... As you start to ascend, ideally the O ring will blow out and you just get a full flood... If not, you will have a ticking bomb on your boat or in the car...

In saying all that, you use liquid electrical tape, resins, my favourite, candle wax to cover all exposed wires as a second line of defence, (Making flooding just inconvenient)

As part of your first line of defence, all cables used should be very round with a good solid sheath; this gives the best seal... Sadly while the LSS-1 transducer cable is round, the heavy shielding leaves air spaces in the cable, hence under pressure it will crush to a spiral cable allowing a gap in the gland seal... So you want a dame good gland and even adding an extra O ring to the cable to help with further depressing the grommet... (Ideally the O ring is added 24 hrs after you have installed the cable & gland, (this gives time for sheath to deiform)

It is very common to use 12V batteries in series as 24, 36, 48V and add a 12V DC convertor and go with large AWG cables ( I am just trying to cheat with one cable and it is not going to work)

Bigkahuna... oops on the 250, and yes i would say good for 15mtrs deep, and yes for ROV with a LSS-1 use an “outdoor Cat5E solid core cable” from the surface (good for a 100m) add cable support to the ROV so it will not kink... add a switch to turn off/on the down-scan ( It is well worth it in the 455Khz, doesn’t do anything for the 800Khz) you can add other single 455/800 transducers (very cheap), may come in handy in zero vis, eyes left, right, front and back, all transducers record depth, simple you toggle through them, if you add motors to move them (check out Dr Depth) you end up with side-scan radar... he has a program for LSS-1 & Humminbirds...

Richard is there a site i can check out the Humminbird that has detail, options on transducer, fish toe depths, good scans poor scans etc...?
Cheers Stu

[bigkahuna]

Lots of good info on Humminbird SI on these two forums:

http://www.xumba.scholleco.com/
http://forums.sideimagingsoft.com/

Thanks for the info, unfortunately the ROV is pretty tiny and I'm limited in what I can mount on or in it. Same goes for the cable, I have to keep the diameter of the sonar cable pretty small otherwise the drag has too big an effect on the ROV's maneuverability.

As for using solid core wires for the cable, I'm as leery of using them as you are of using batteries in your fish. Solid core wire is designed to be used in fixed installations, even the ABS bans them for use in boat wiring because the strands will eventually break even when "rigidly" mounted inside a boat. I'll only use stranded wire cable, but I may either have to compromise with the total length or go with a larger diameter wire to compensate for losses.

[Rickard]

Stu,

Bigkahuna has already sent you the most comprehensive Humminbird forums. As you may have noticed, there has been alot of development of add-ons done for the Humminbirds.

(If you are curious about Bigkahuna's and my activities, we use the same nick names in the other forums. )

I know the sealed batteries are not 100% sealed, but some models have valves to relieve pressure during charging. These valves will (do their best to) prevent water from getting in. Of course, there's always a risk for water ingress and therefore also a risk for a `boom´ when the battery returns to the surface (I once lost a dive lamp that way). But the valve will let the pressure out - if it hasn't got stuck during the dive..... I like the attitude they have to underwater issues here: http://www.submarineboat.com/ This site is probably familiar to you, but I must emphasize the practical and bold style of their projects. It struck me when I read about waterproof potting of electronics that even the circiut board(s) in the LSS-1 could be potted in some resin/plastic. This way one could get rid of much of the housing and cable sealing issues. But if it fails.... ?

Regards,
Rickard