Lowrance LSS-2 Transducer Installation and Use

[porthole]

I am installing a LSS-2 and Airmar TM150 transducers on the stern of my 1999 21 Outrage. The instructions and most of what I found on the web seem to favor some type of stepped hulls.

The LSS-2 is just over 10-inches long. and I see that as making the install a bit more challenging. For now I have it mounted left of the lower unit. The Airmar will go on the starboard side of the engine and above the installed height of the LSS-2.

Has anyone here mounted a LSS-2 yet?

Those that have, do you have to tilt the outboard up to have an effective beam from the transducer?
It appears that I may have to tilt the engine almost to the lift cylinder for the LSS-2 to have an unblocked 'view'.

[Hoosier]

I went to the Lowrance "Transducer Selection Guide" and found that the DSI Skimmer beamwidth is 12 degrees at 800 kHz, and 6.4 degrees at 455 kHz. At those beam angles it won't "see" your lower unit.


DSI Skimmer, Transom / Trolling Motor (with adapter), 800kHz, 455kHz
Mounting: Transom / Trolling Motor (with adapter)
Boat type: outboards, I/O
Hull type: Any
Elements: 1 Internal Broadband Ceramic (1 Hi)
DownScan™ imaging Depth and Temp
Plastic housing

Frequency Angle Beamwidth
800kHz

12° 63ft

Frequency Angle Beamwidth
455kHz

6.4° 34ft

Now to muddy the waters, I question the accuracy of this data because beamwidth narrows as the frequency goes up, I think they reversed the numbers.

[porthole]

Not sure how the DSI Skimmer relates.

The LSS-2 has a multi element receiver, left right and down. According to the Lowrance website it is 180 degrees of coverage.
About 3/4's the way down on this page.

http://www.lowrance.com/en-US/Support/Transducers/

With a graphic that is posted it looks close to about 150 degrees.


I posted these questions to the Lowrance tech support but haven't heard anything yet.

With trim tabs, a flat stern and hull bottom shape, there really is not a lot of room for an ideal location.

[Acseatsri]

I have one mounted on my 23 Walkaround. It was originally transom-mounted, but in that position it would only see the side opposite the lower unit. I ended up making a 20 degree fairing block and mounting it directly on the bottom of the boat. It now sees both sides of the bottom contour equally well. It works particularly well looking for rockpiles when black fishing, but I haven't found the sidescan particularly useful for most saltwater fishing. I'm glad I got the transducer for free, as it wouldn't have been worth the $300 cost.

[Hoosier]

I had to go ask Lowrance about the LSS-2 since it wasn't included in their Transducer Selection tool; they don't consider it a transducer but an "imager". Anyway here's what I got from them:

DSI and LSS beam angles and info
What is the cone angle?
LSS1 @ -10dB:
455: 70° x 6°
800: 50° x 3.2°

DSI @ -10dB:
455:70⁰x12⁰
800:50⁰x6.4⁰

Same as structure scan going port to starboard.  Fore to aft 2 times wider due to smaller xdcr.
800KHz:   1.58deg x 31.75deg (-3db)
455KHz:   2.79deg x 55.82deg (-3db)

What type of coverage do you get?
Very similar to the down coverage on structure scan, although it may seem like you get more coverage on structure scan because the side channels bleed into the down.

(I interpret this to mean the beam is a fan, not a cone, with a vertical beamwidth of 6 degrees and a look angle of 70 degrees on each side for a total of 140 degrees at 400 kHz. So, what I would do is to get a protractor and measure where 70 degrees "sees" from my transducer mounting point to be sure it's low enough to clear the skeg.)

What is the difference between 455 and 800 kHz?
800KHz – crisper image due to narrower fore to aft cone angle, less port to starboard coverage, less depth range due to absorption of higher frequencies.
455KHz – smudged image due to broader fore to aft cone angle, increased port to starboard coverage, more depth range due to decrease in absorption of lower frequency.
How fast will it work?
We look to be on track to work up to 50mph.  Best images are generated when going 2-8mph.

[porthole]

I got an answer from Lowrance.


Question:
Hello, I can't find the specs or info I need to install, HDS 7 Gen 3 with an Airmar TM150 and LSS-2 transducers.
It is my understanding that the LSS-2 has 3 transducers, 2 side imaging and one down image, is that correct?
What are the beam angles?
Horizontally, how far towards the surface does the beam go? Or asking another way, looking from the rear of the boat forward, how much of the water column is covered by the beam?
Am I correct in understanding that because of side imaging, I will have to raise the outboard to the point where the lower unit is not "in sight" of the LSS-2?
It is my understanding that side imaging is not very effective above approximately 5 mph, is that correct? If so, Mounting the transducer so that it is above the bottom of the boat a bit should not affect it's use, correct?

Answer:
Thank you for your inquiry.

The LSS-2 has multiple crystals inside it to give you down and side imaging.
The side imaging cone angle is 180 degrees on the left and right side.
We recommend that the LSS-2 is at the lowest point of the transom so the outboard will not interfere with the LSS-2 transducer.
To get the best picture you will need to run at about 5 mph, but run up to 10 mph but the picture will not be as clear.

[porthole]

I had to go ask Lowrance about the LSS-2 since it wasn't included in their Transducer Selection tool; they don't consider it a transducer but an "imager". Anyway here's what I got from them:

DSI and LSS beam angles and info
What is the cone angle?
LSS1 @ -10dB:
455: 70° x 6°
800: 50° x 3.2°


(I interpret this to mean the beam is a fan, not a cone, with a vertical beamwidth of 6 degrees and a look angle of 70 degrees on each side for a total of 140 degrees at 400 kHz. So, what I would do is to get a protractor and measure where 70 degrees "sees" from my transducer mounting point to be sure it's low enough to clear the skeg.)

Is this a typo
LSS1
Or are the LSS1 and LSS2 the same regarding elements?

The answer you got seems to make a little more sense. A left and right element at 70 degrees each from horizontal with bleed over coverage from the 70 degree downscan coverage.

[porthole]

I have one mounted on my 23 Walkaround. It was originally transom-mounted, but in that position it would only see the side opposite the lower unit. I ended up making a 20 degree fairing block and mounting it directly on the bottom of the boat. It now sees both sides of the bottom contour equally well. It works particularly well looking for rockpiles when black fishing, but I haven't found the sidescan particularly useful for most saltwater fishing. I'm glad I got the transducer for free, as it wouldn't have been worth the $300 cost.

Have any pictures of what you did?

Did you notice any performance differences with the change, such as listing at speed?

I have yet to water test mine. My boat is a 21' hull with trim tabs. Because of the tabs both transducers are currently mounted in the same relative position from port to starboard. Because of the length of the LSS2 there is little room for mounting options once the outboard is trimmed all the way in. I can move it towards the center a bit, but for now it was installed on an existing Stern Saver block.

I am tempted with the idea of making a fairing block and mounting it on the bottom. Something along the lines of a homemade Stern Saver.

[porthole]

I have one mounted on my 23 Walkaround. It was originally transom-mounted, but in that position it would only see the side opposite the lower unit. I ended up making a 20 degree fairing block and mounting it directly on the bottom of the boat. It now sees both sides of the bottom contour equally well. It works particularly well looking for rockpiles when black fishing, but I haven't found the sidescan particularly useful for most saltwater fishing. I'm glad I got the transducer for free, as it wouldn't have been worth the $300 cost.

I think I am with you on the saltwater part and the cost. I am beginning to think that the LSS2 transducer and feature set is more geared towards the freshwater bass anglers. Almost all of the advertising and you-tube videos are on bass boats.

Yesterday I gave [the LSS-2 side scan SONAR] a test. Went out to try and find some wreck blackfish. First impressions are the side scan and down scan images in my river are no where near the quality and views I have seen on the net. Running along a bulkhead and docks, the only way I would know what was being displayed was knowing what was alongside me.

Out on the ocean it seemed useless. What I especially did not like was when the LSS2 and Airmar TM150 were active, the Airmar TM150 display changed to something that was dull and almost like the LSS2 displays. I like my bright color pallet for the regular SONAR. I did not like the display at all with both transducers active.

I was not impressed with the performance using just the Airmar TM150 transducer on the open water looking for wrecks. Although I may have had an problem with the transducer position. The Airmar bracket will swivel up if hit by an object. When I got home last night I found the transducer has snapped out of its locked position. What I don't know is when it was knocked out of position.

I have a steep ramp and launched and recovered yesterday within two-hours of a full-moon low tide. And the launch and recovery were less then graceful. The SONAR transducer could have gotten knocked anytime from launch to home. But I now know to check it with a boat pole after launching.

[porthole]

Photograph of display screen with only the Airmar [model TM 150 transducer] active



Both active. [Notice palette color shift in left side sonogram.]

[jimh]

If you are in only 5.7-feet of water I would not expect the range of the side scan to go very far. Isn't the range of the side scan SONAR related to the water depth?

ASIDE: You should be able to get a much better image of the screen by using the built-in screen capture utility.

[porthole]

If you are in only 5.7-feet of water I would not expect the range of the side scan to go very far. Isn't the range of the side scan SONAR related to the water depth?

The side scan, according to Lowrance is a 180 degree view left to right and only a couple of degrees front to back (4-6 degrees I think).
Although I did not receive information as to how far out it will return pings horizontally.
I can only assume that the top right SONAR return in this picture is indeed looking out 60 feet in the water that is about 8' deep. Using the sand ripples as a gauge.



The left side scan is shooting out towards the center of the river, which is only a few feet deeper (this was near dead low tide).
The right side scan is probably 50-70 feet from the waters edge, so from the boat out to the right it gets shallow quickly. That might explain why the return looks different form side to side.

ASIDE: You should be able to get a much better image of the screen by using the built-in screen capture utility.

Indeed I can, but I had to get the manual out to figure it out. Very similar to the iPhone and iPad. Press the "pages" and "power" buttons at the same time and a png screenshot is saved to the "files" folder on the HDS.

From there you go into Files and find the screenshot folder. Menu choices allow you to copy all or select files and then paste them into a different folder, preferably on one of the SD cards that can then be popped out and read on a PC.

I could not find a way to wirelessly send the pictures.

[jimh]

If the reports from other users are correct, you should be able to ftp to 192.1681.1.1 and see the files. There are a zillion ways to run an ftp client. I don't know which one you are familiar with. What type of computer are you using? Mac/Unix/Windows?

[porthole]

MacBook Pro with a bootcamp partition with Win 7 Pro.

[jimh]

To ftp with MacOS, just open the TERMINAL application. Then use the ftp command

ftp 192.168.1.1

to connect. For user-id use anonymous, and for password try blank password.

[jimh]

If a side scan SONAR transducer is operating in 6-feet of water and tries to get an echo from an target that is 60-feet away, the cone angle echo coming from the object 60-feet away and on the bottom relative to straight down to the bottom would be

ARCTAN (60/6) = 84.3-degrees

The distance to the target would be 60.3-feet, compared to the distance to the bottom of 6-feet.

I need some expert help to calculate the difference in signal propagation loss for the two paths, one of 12-feet and the other of 121-feet. What would the difference in attenuation be for freshwater or seawater at a frequency of 100-kHz?

[jimh]

Using a calculator at

http://resource.npl.co.uk/acoustics/tec ... bsorption/

for a frequency of 400-kHz, and for the typical seawater values for salinity, pH, and temperature, the attenuation of sound due to absorption was calculated to be between 94 and 98-dB per kilometer. Converting to dB per foot that would be 94-decibels per 3280-feet, or 0.028-dB per foot.

For a range difference of (121 - 12) feet, the difference in signals would be only 3-dB.

A difference in signal level of 3-dB is much less than I would have thought.

[porthole]

To ftp with MacOS, just open the TERMINAL application. Then use the ftp command

ftp 192.168.1.1
to connect. For user-id use anonymous, and for password try blank password.

I get an error of "connection refused".

But, it gave me an idea.

Looked up the MAC address on the HDS @ 'settings' - 'wireless' page
Opened up my router admin in a browser and found the attached device with the matching MAC address.
Copy & paste the associated IP address and pasted that into a browser.



Clicking on the hyperlinked "Logs" opens up "Index of /userdata/Logs"
Once on that page all of the folders on either inserted SD card are visible and can be opened.

entering "ftp://" in front of the IP address opens directly to the file structure showing the left and right memory cards and the userdata/ folder

Don't know why, but all of the screen shot files with extension .png can be opened or downloaded.
The wallpaper files with a .jpg extension are shown but cannot be accessed.

[porthole]

My transducers. Port side is the LSS-2, Airmar TM150 on the starboard. Hard to tell, but the LSS-2 is slightly below the height of the TM150.
The blue tape and mark is how far toward the center I can go without hitting the lower unit on turns. So I could get it a couple inches lower. Since it is a low speed device I'm guessing the prop will not interfere to much.





As far as quality of side scans go, I would hope to be able to achieve results like this (taken from the Lowrance facebook page)

[jimh]

It sounds like the WiFi base unit in your HDS Gen3 must have taken on a different ip-address. If you have other WiFi devices around, that address migtht already be in use. Another common address is 192.162.1.254.

What was the ip-address that you found the WiFi base was using?

[jimh]

That submarine screen capture is amazingly good. That is not side scan--what made that image?

[porthole]

What was the ip-address that you found the WiFi base was using?

192.168.1.47

[porthole]

That submarine screen capture is amazingly good. That is not side scan--what made that image?

It is a side scan, just not a consumer oriented unit like one might be led to believe looking at the Lowrance Facebook page. Towed fish, Klein, Deepvision etc. If you google "side scan sonar images", the sub image happens to be one of the top images in the search.

[jimh]

From your results at using a web browser to visit your HDS-12 Gen3 device (as seen in the screen captures above), it appears that in addition to having an FTP server built into the device there is also an HTTPD server--a web host--built into the device, too. That is quite interesting. I guess having a web server built into a device is becoming the norm these days. Soon we will have toasters with their own built-in web servers so you can control the toaster from your smartphone.

[Acseatsri]

I snapped a couple pictures of the transducers. Wires aren't secured because I'm doing some work in the area.

image.jpeg (203.47 KiB) Viewed 32118 times

image.jpeg (163.55 KiB) Viewed 32118 times

As far as any adverse effects from the boat bottom mounted transducer, there is no noticeable difference in the running characteristics of the boat. The fairing block is a 1" thick piece of HDPE with a 20 degree angle cut on the bottom to match the deadrise of the boat bottom and tapers down to about 1/16" thick at the thin side.

[porthole]

Did I screw [the transducer or fairing block] to the hull?

I wrote to Stern Saver about a block, no answer after a week. If I can find a piece of plastic thick enough I may make my own, with the same concept as Stern Saver. Drill and bottom tap several 1/2" - 5/8" holes and fill with epoxy. If I can get a piece of plastic thick and wide enough, I might try recessing the transducer flange .

[jimh]

Did you paint the transducers with any sort of special anti-fouling paint?

[Acseatsri]

It is screwed to the hull using #6 stainless flathead screws, using 5200 to seal it. Holes were not drilled thru the fiberglass and into the foam. To get holes the right depth and the screws the right length took several tries. The holes are drilled only 3/8-inch deep.

Another note: if you use high-density polyethylene (HDPE) for the fairing block, be sure to cut some dovetail slots (or shallow holes that are bigger at the bottom than the top of the hole) in the bottom of the block so the 5200 can fill and allow a mechanical bond to the HDPE. A dovetail slot is smaller at the surface than it is as you go deeper and is the same principle as a Stern Saver.

The transducers are spray painted with a special anti fouling paint specifically for transducers.

[rnvinc]

I suspect that your lower unit and your TM150 are blocking some of the right [side image] beam and causing the darker right side in your [side image sonogram]. You can test this by tilting up your motor and temporarily removing the TM150 (in the same water and bottom conditions rendering this darker right side imaging).

We have to remember that the beam angle specs published on any Sonar manufacturer's nomenclature is merely a "measurement at a point in the attenuating sound travel" and NOT where the sound pulse stops. The sound pulse continues past the published beam angle spec (-3db or -10db) until 0db (absolute silence). Any object (even outside of the published beam angle spec) that is close enough or reflective enough can block some of the sound pulse.

[jimh]

Whether or not the gear case of the outboard engine as seen in the image above interferes with the sound beam of the side-scan transducer depends on how far aft of the transom the engine gear case sits, how far aft of the transom the transducer sits, and what the beamwidth of the transducer is in the fore-and-aft plane. Usually a side-scan transducer has a response characteristic like a fan, that is, the beamwidth is very wide in the port-starboard plane and very thin in the fore-aft plane.

The TM150 is located 90-degrees off the center downward axis of the other transducer, so it would only be interfering with the sound beam of the side-scan transducer at angles that were just about horizontal. I don't think the beamwidth of the side-scan transducer is really 180-degrees.

However, it would be simple to test for the influence of the outboard engine, as mentioned, by just tilting it up while operating the side-scan.

When the scan (shown far above with the right side scan image somewhat dark) was made, if the water to the starboard side of the boat was much deeper than the water to port, would that also affect how the sonogram would appear? Maybe there were no returns from the starboard side because the transducer was pointing into much deeper water.

[porthole]

The outboard was tilted enough to not interfere with the side scan beam.

The screen shots on this post - the starboard, darker side is shallower water, in about 100 horizontal feet or less it goes from the displayed depth to zero.
http://continuouswave.com/forum/viewtopic.php?p=1811&sid=f7ade5e123c7c879a667f63dfb849a79#p1247

If you look close you can see that even under the boat the left and right beams show different depths, with starboard shallower.

[jimh]

I don't see any information in any of the sonograms that tells you how deep the water is in the side scan images. The side scan panel has three axis of information : top-to-bottom axis of image, left-right axis of image, and Z-axis or pixel intensity. These are illustrated below:

timeAxis.jpg (24.84 KiB) Viewed 30915 times

The oldest echoes scroll off the display at the bottom, and the newest echoes come on display at the top. This axis maps the history of echoes.

distanceAxis.jpg (25.26 KiB) Viewed 30910 times

The time between transmission and reception of echoes is proportional to the distance to the reflector. This is presented for two transducers, one facing to Starboard and one facing to Port. Starting from the center line, the echoes are farther to Port or farther to Starboard of the boat. This axis maps the distance of echoes. The graduations, zero in the center and 60 at each corner, represent the calculated distance away (in feet) based on the interval between sending the signal and getting a reflection from a target. For targets close to the boat, the distance is mostly downward, and for targets farther away, the distance begins to become an angle increasing from straight below the boat to straight out to the side.

echoStrengthAxis.jpg (28.4 KiB) Viewed 30915 times

The strength of the echo is represented by the brightness of the pixel; stronger echoes are drawn with brighter pixels. No echoes are drawn with black pixels. This axis maps the strength of echoes.

Where is the water depth shown?

[porthole]

Using the pictures in your post.
I am traveling west on Shark River between two bascule bridges. The river in this section is not buoyed, but does have a commonly traveled safe navigation area.
The boat is about in the center of the deepest part, 14' and the shoreline, 1-2' above sea level. I am probably less the 75-100' from either extreme.
Since the boat is traveling across a sloped area, it can be seen on the side scan image.

Looking at the image, "0" representing the centerline of the transducer, the dark area between that centerline and the beginning of the bottom side scan returns on either side is the water column. The sonar is returning a depth of 5.7' under the transducer.

If you look closely at the image you can see the the water column to starboard is slightly shallower then to port.
The display is not showing a digital depth reading on either side, only the current depth under the transducer which is an average of the cones coverage area.

[porthole]

Here is a pretty good real "3D" explanation.

http://m.youtube.com/watch?v=3xe6pLPdMKc

[jimh]

The 5.7-feet comes not from the left-right side scan presentation. It comes from the downscan presentation, seen in another window. There is no depth information in the left-right side scan presentation. If there were depth information in those sonograms, you wouldn't need to explain to me the circumstances of the waterway when you took it. The depth would be measurable from the sonogram. I don't see any depth information in the sonogram.

And there is no "3D' in that presentation at all. It is just 2D with echo strength.

[porthole]

The 5.7-feet comes not from the left-right side scan presentation. It comes from the downscan presentation, seen in another window. There is no depth information in the left-right side scan presentation.

Yes I know, maybe I was a little to generic in my wording. The 5.7' is coming from the TM150, super imposed on whatever screens the software will allow it to be displayed.

If there were depth information in those sonograms, you wouldn't need to explain to me the circumstances of the waterway when you took it. The depth would be measurable from the sonogram. I don't see any depth information in the sonogram.

The dark area on either side of that center white line out to the bottom return is the depth of water, the water column below the transducer. Just because there is no scale or digital numbering doesn't mean there is no depth information, it just is not quantified. That water column is the depth, whether on a $500 Humminbird, $1500 HDS Gen3 Lowrance or a $150,000 Klein 5000.
Now, if there was not a second transducer such as the TM150 in my case, then one would have to interpolate the depth

And there is no "3D' in that presentation at all. It is just 2D with echo strength.

3D as in folding a piece of paper printed with a side scan image to show in 3D how the image is referenced. It is a pretty good video to give someone the general idea on what is under your boat and how it is displayed.

http://m.youtube.com/watch?v=3xe6pLPdMKc

[jimh]

The center part of the side scan display only shows the depth right under the boat. It can't show the depth for targets that are 60-feet away--at least I can't see how it could with the presentation we are seeing.

Also, that earlier image posted showing the submarine--that's not at all like this recreational side scan left-right sonar. Lowrance has just introduced something that might be akin to that submarine image, and they're calling it 3D. It is a psuedo-3D presentation of echoes with a true three-axis layout. But it takes a lot of graphic manipulation of historical echo data to create the image. You aren't going to get anything like in the left-right side scan presentation.

[Acseatsri]

I think trying to look 60' to either side in less than 6' of water is the biggest problem with your screen shot. You'll get a much better rendering if you cut down the side scan distance.

[porthole]

The center part of the side scan display only shows the depth right under the boat. It can't show the depth for targets that are 60-feet away--at least I can't see how it could with the presentation we are seeing.

I never suggested that depth of targets 60' out could be read. I only said that while viewing the water column, e.g. depth of water under the transducer, that you could see a difference in depth from port to starboard.

Also, that earlier image posted showing the submarine--that's not at all like this recreational side scan left-right sonar. Lowrance has just introduced something that might be akin to that submarine image, and they're calling it 3D. It is a psuedo-3D presentation of echoes with a true three-axis layout. But it takes a lot of graphic manipulation of historical echo data to create the image. You aren't going to get anything like in the left-right side scan presentation.

I grabbed the sub scan off the Lowrance facebook website. Shame on Lowrance for alluding to the capabilities of their unit.
It was a bit tongue-in-cheek wishing for an image like that from a recreational unit. The media put out by Lowrance on the imaging quality is quite good. I am hoping that with some use I will get the same results. I am 99% sure that sub image is from a $10,000 Deepvison towed fish side scan.

[porthole]

I think trying to look 60' to either side in less than 6' of water is the biggest problem with your screen shot. You'll get a much better rendering if you cut down the side scan distance.

That was the first time I used the HDS side scan, and I only had an hour or so to try it out.