Humminbird Side Imaging Forums

Other Interest => DIY - Side Scan Sonar and towfish => Topic started by: Rickard on September 08, 2009, 09:37:13 AM

Title: Longer array and narrower beam
Post by: Rickard on September 08, 2009, 09:37:13 AM
Hi,
I want to build SI arrays which are longer and have narrower beams than the original HB transducers have (they are about 1.5 degrees at -3dB and 455 kHz). Therefore I need piezos which match 455 kHz. I have tried contacting the technology development people at HB but they are not responsive. Does anyone have any ideas on where I can get hold of suitable piezos? A plan B could be retrieving piezos from broken SI transducers, but my own transducers are all still functioning (does anyone know how many SI elements there are in one array in the SI transducer?), so a plan C could be joining two transducers into one super-ducer twice as long as the original. (This would involve grinding away material from the transducers to bring the piezos close enough together while hoping the transducers have the same internal dimensions. ???)

Why?
SI arrays operated at 455 kHz with about 0.7 degree -3dB main beams would have good range performance and they would extend the area covered at a specific horizontal resolution four times when I do 360 degree scanning under ice. (When moving in a straight path the area is doubled so in normal scanning this improvement is less important). Also, if the 262 kHz channel can be used the image will have better resolution than the original transducers give at 455 kHz. Any comments are welcome, even those which will kill the project instantly!   :)

Rickard
Title: Re: Longer array and narrower beam
Post by: keizerh on September 08, 2009, 01:33:33 PM
Did you contact airmar already?
They have european headquarters in Birkerod Denmark.

hendrik
Title: Re: Longer array and narrower beam
Post by: Rickard on September 08, 2009, 03:30:45 PM
Thanks Hendrik,
I have looked through their website but there seems to be no product that fits my needs. They have a custom design page where you can fill in an inquiry, perhaps it could be worthwhile trying that.

Rickard
Title: Re: Longer array and narrower beam
Post by: keizerh on September 08, 2009, 04:14:09 PM
Not everything they build is on the site.
I know the build sophisticated ones as wel. The fased-array from interphase is also theirs.
You can give it at try at least.

hendrik
Title: Re: Longer array and narrower beam
Post by: Humminbird_Greg on September 14, 2009, 02:38:06 PM
RadarSonics is also a transducer manufacturer.  Not sure where they are located out of or if they have an overseas (to me at least) facility or not but may be worth checking.
http://www.radarsonics.com/ (http://www.radarsonics.com/)

Title: Re: Longer array and narrower beam
Post by: Kimi on December 22, 2010, 02:03:51 PM
Here is an interesting link about this subject!

http://www.beugungsbild.de/sidescan/sonar_index.html (http://www.beugungsbild.de/sidescan/sonar_index.html)


Kimi..
Title: Re: Longer array and narrower beam
Post by: Rickard on December 22, 2010, 02:47:33 PM
Kimi,

Yes, it's interesting and it was the source that made me develop beamform simulations myself. I have built several arrays based on the idea that unequal spacings between elements will suppress sidelobes. However, I couldn't confirm René's results in my simulations and in the end I contacted Institutt for informatikk in Oslo and they confirmed my suspicions that something was wrong with René's results. René put in a comment on this on his homepage in 2007. The sparse array concept is as old as radar and sonar theory and it has been shown that only minor improvements are possible with this method.

Despite that, I built a few experimental arrays with unequal spacings in order to see what happened in reality. These projects have been reported here: http://www.geotech1.com/forums/archive/index.php/t-13311.html (http://www.geotech1.com/forums/archive/index.php/t-13311.html)
(unfortunately, the images disappeared when the forum moved to a new host)

I knew that full suppression of sidelobes require less than 1/4 of a wavelength spacing between the elements, so I finally made an array with that feature: http://www.xumba.scholleco.com/viewtopic.php?t=778 (http://www.xumba.scholleco.com/viewtopic.php?t=778)
Thus, it is possible to build a working sidescan array using fishfinder transducer.

Nobody engages in these kinds of projects anymore, the HB SI units have made them unnecessary.

Now, as this thread has become active again, I can't resist disclosing my Christmas project, I will try to join two SI transducers into one long transducer. If that fails, next step is retrieving the piezos and build a long transducer from scratch. The brand new transducers are already in my drawer. :)

Rickard
Title: Re: Longer array and narrower beam
Post by: Jolly Roger on December 23, 2010, 06:13:30 AM
Now, as this thread has become active again, I can't resist disclosing my Christmas project, I will try to join two SI transducers into one long transducer. If that fails, next step is retrieving the piezos  and build a long transducer from scratch. The brand new transducers are already in my drawer. :)

Rickard

 :o  :o
Allthough this talking about sidelobes and arrays and stuff is way over my head (not only the English), I understand that you're planning to butcher two brandnew transducers, right? Holy smoke!

I'm curious to see your results and wish you all the best and success Rickard. Keep us posted about the outcome  ;).

Best regards and merry Christmas

Harry
Title: Re: Longer array and narrower beam
Post by: Rickard on December 23, 2010, 08:59:10 AM
Thanks Harry,

Yes, I will 'butcher' the transducers, but first I will only drill a few holes down to the piezos to verify that the internal positions are similar enough to permit joining the transducers without too much destruction (the magical figure 1/4 of a wavelength (about 1 mm at 455 kHz) comes in here, precision must be better than that). If this is possible the transducers will be possible to fix afterwards if I regret the whole project. If, on the other hand the transducers differ too much the complete butchering is unavoidable.  I will be back with reports on how this develops. Now, there will be a few days with celebrations with relatives so the sonar projects take a rest.

Merry Christmas Harry!

Rickard
Title: Re: Longer array and narrower beam
Post by: sonar2000 on December 23, 2010, 09:15:08 AM
While this takes considerable skill above most of us,  the end product may be something to consider. Should this venture prove successful in all ways then you might want to consider getting the individual components and building from scratch.
You very well may be onto a new innovation.
As Harry said this is way over a lot of us but that is not to say it is not interesting and exciting.
Good holidays and let us know when you are back on the project.
Chuck (sonar2000)
Title: Re: Longer array and narrower beam
Post by: Kimi on December 23, 2010, 04:28:04 PM
Nobody engages in these kinds of projects anymore, the HB SI units have made them unnecessary.

Thats true, life goes easier that way, but in otherhand.. I give my full respect to these DIY guys who show us how things could be done, and made.

As Harry said this is way over a lot of use but that is not to say it is not interesting and exciting.

Exactly! But knowledge is not "heavy to carry". Ewen If we could know just a little bit moore each day, it helps us to understand how our equipment relly works.

Thanks Rickard.

And Merry Christmas to eweryone!


Kimi..

Title: Re: Longer array and narrower beam
Post by: abraquelebout on December 23, 2010, 05:38:24 PM
interresting subject rickard
i have not book or paper who speak about this, my poor inglish don't let me understand technical revue.
if you want 455 khz piezzo why don't you take this transducer[attachment=1]
it's the SH-B06T
he work in 455 khz but not 800 (i make experience)
262 khz may be a good solution to take larger scaning ??
merry christmas to every one
Title: Re: Longer array and narrower beam
Post by: Rickard on December 24, 2010, 08:00:20 AM
I will use the older transom mount SI transducers with 262 and 455 kHz. Making a long transducer will not qualify as a new invention really, joining two transducers is just a practical(?) way of getting one. The basics in sonar theory are actually very simple. They are just applications of wave-theory. I learnt these basics by going through the material here: http://www.omg.unb.ca/GGE/SE_3353.html (http://www.omg.unb.ca/GGE/SE_3353.html)
I can guarantee you will have a number of very interesting hours if you go through the presentations!

Now they are calling me to the Christmas dinner table! Merry Christmas all!

Rickard
Title: Re: Longer array and narrower beam
Post by: Rickard on December 31, 2010, 07:22:56 PM
First step

Transducer no 1 has been cut and left and right array of piezos can be seen from the rear. The piezos are 5 mm thick and 6 mm wide, length is unknown. The piezos on left and right side are not positioned with exactly the same distances to the walls of the housing. The error is about 0.5 mm but less than the critical limit 1 mm. As shown in the photo, sound must travel through two types of resin, some kind of flexible epoxy and PVC before water is reached. The dimensions of the piezos are difficult to relate to the resonance frequencies, 455 and 262 kHz. 455 kHz is probably the resonance frequency in the thickness mode and 262 kHz is possible to get as the first overtone in a piezo that is about 26 mm long. This leaves room for a third frequency, about 380 kHz in the transverse mode, but this frequency is not presented as an option in the instruments. I had to sacrifice temp because the wires were impossible to avoid when cutting. The inner walls of the housing and the cork-insulation of the piezos have copper shields. This shield can prevent from some electrical interference, but I think it also provides a radio shield that stops radiation emitted from the piezos.

Next step, cut the other transducer and compare positions of piezos with transducer no 1. This comparison will tell if the transducers can be joined and (hopefully) work as one long transducer

Rickard[attachment=1]
Title: Re: Longer array and narrower beam
Post by: sonar2000 on December 31, 2010, 07:32:21 PM
Very very interesting. Glad you have the transducers to cut apart.  Too bad that Humminbird would not send you two transducers unassembled for you to play with.  Every one could have benefited from this project. If successful you may have to go into a production mode. Unless HB wants to hire you... ::)
I watched the transducers being assembled in Eufalua at the HB plant.  It would have been very nice to have all the components apart and to start from the beginning to join.
Best of luck on this and please keep us informed on your progress.
Great effort and work on your part..
Chuck
Title: Re: Longer array and narrower beam
Post by: Rickard on December 31, 2010, 08:07:42 PM
Chuck,

I tried with the technology development folks but bureaucracy prevented them from sending me parts. HB has tested long transducers, but they didn't help the images enough in regular use so they dropped the idea. Since I have rotation scanning under ice in mind I can expect much better results with a long transducer. This application is not common enough to motivate serial production, I think.

Rickard
Title: Re: Longer array and narrower beam
Post by: Del on January 01, 2011, 04:42:05 AM
Rickard, i think you smashed your warranty  ;D


No seriously, this is really really interesting and i hope you'll get some positive results! I just started going through the link you provided, and to me its "heavy stuff" but its giving some ideas and even if i don't understand all of it (both, sense and language) it really helps to understand the technology. Thanks a lot for sharing your informations.


Happy new year,
Del
Title: Re: Longer array and narrower beam
Post by: Rickard on January 01, 2011, 03:27:04 PM
First setback

When exposing the front end of the second transducer a problem appeared, cables are routed in front of the piezo and they seem to be impossible to reroute because of no space between piezo and housing. I have to uncover the rear of the second transducer like I did with the first and join the rear ends instead. One transducer will be oriented backwards in the final long transducer and the sidescan channels must interchange in the backward transducer.

Rickard
[attachment=1]
Title: Re: Longer array and narrower beam
Post by: Jolly Roger on January 01, 2011, 05:23:45 PM
Rickard,

you're unbelievable!

My deepest respect and best wishes for your project. Keep us posted about your progress.

Regards / Harry
Title: Re: Longer array and narrower beam
Post by: sonar2000 on January 01, 2011, 05:24:27 PM
Sure glad you are in the builder's seat of this project.  I can see some applications for this if successful which are beyond fishing.
Recovery of victims or other submerged items when the surface is ice covered may help the teams with safety if the target can be seen before divers enter the ice hole.
Keep us informed.  And goodluck.  I hope you will get some assistance with the project.
chuck
Title: Re: Longer array and narrower beam
Post by: abraquelebout on January 02, 2011, 05:13:18 AM
hello rickard
interresting thing, why don't you use medical radiography to see the interior of the transducer ??
i contact one of my friend if it's possible...
Title: Re: Longer array and narrower beam
Post by: Rickard on January 02, 2011, 07:10:34 AM
Hi,

I have thought about x-ray but have no such resources here. Today I cut the rear end of transducer no 2 and found that the internal positions of the sidescan piezos differ from the positions in transducer no 1. The right array, as seen from behind, is mounted too close the housing, it almost touches the wall. This means the left and right arrays are at least one mm farther apart in transducer no 2 compared to transducer no 1. Also, the right array is located about one mm closer the front than the left array. I think I have to conclude that the precision inside the transducers is too low. I'm afraid it's not possible to join these transducers and expect a high quality image. I will think this over now before I go ahead and cut up the transducers to retrieve the piezos.

The photo is from transducer no 2. Note that the right piezo is very close the housing.

I'll be back
Rickard
Title: Re: Longer array and narrower beam
Post by: Jolly Roger on January 02, 2011, 08:02:07 AM
Rickard,
check your PM box.

What sort of plastic is in the housing to keep the piezos in place. Can it be disolved by some solution or other chemical stuff?

Regards / Harry
Title: Re: Longer array and narrower beam
Post by: Rickard on January 02, 2011, 09:56:19 AM
Harry,

Thanks for the PM. The opaque plastic inside the transducers smells like burnt rubber when I cut it, perhaps that's a clue for what type of compound this is? Acetone will probably dissolve everything, including the insulation of wires. I will try carving in the first place, that will save the wire insulation and it will likely be a quicker method.

Rickard
Title: Re: Longer array and narrower beam
Post by: Jolly Roger on January 02, 2011, 10:10:01 AM
Quiet tricky what you are doing Rickard, my deepest respect!

I'm confident that you will take your time to get the "rubber" out. Working with tiny wires needs patience and a long breath  ;).

I'll keep my fingers crossed.

Regards / Harry
Title: Re: Longer array and narrower beam
Post by: abraquelebout on January 02, 2011, 11:57:45 AM
i contact my friend who work on hospital, he must make the x-ray picture of the transducer
this week  :D...i'm waiting ;)
Title: Re: Longer array and narrower beam
Post by: Bob B on January 02, 2011, 02:16:38 PM
Rickard, I don't want to open a "can of worms", but to what extent would the deviation in piezo placement affect the si transducer performance?  :-\
Title: Re: Longer array and narrower beam
Post by: Rickard on January 02, 2011, 03:41:21 PM
Bob, here comes the worms :)

It's hard to tell exactly what the practical effect will be. There are at least three separate errors in this case. First, the piezos won't line up in a straight row, at least not on one side. Second, there will be a 1.5 - 2 mm shifting sideways in the middle of one of the arrays. Third, a 2 mm gap will occur between the middle piezos in one array. These errors may be acceptable at 262 kHz but at 455 kHz I believe they will cause ghost images and blurr. It's possible to calculate the precise loss in sidelobe suppression for simple cases like a 2 mm inter-piezo gap, but my simulation program is in a computer 900 km away from here.

But perhaps we will see what these errors really mean because my present idea is to join the transducers after all and line up a perfect(?) array on one side and let the other side take all the errors. Then I will have a good channel and a bad channel and we can inspect the practical difference. The joined transducer can also be run with a long array (right channel) and a normal array (left channel) at the same time and even the practical difference between normal and long good arrays can be observed.

Rickard

Title: Re: Longer array and narrower beam
Post by: Bob B on January 02, 2011, 03:57:53 PM
Thanks for the response Rickard.

I studied electronics and communications in my youth, so I have somewhat of an understanding of wavelength interactions, but my knowledge is very old and not used in a long time.  Just started wondering if the accuracy of putting the transducer together might explain why some people are able to achiever better images than others.

I do find your project very interesting, but definitely don't want to kijack your post and put it in a different direction.

I had actually came back to delete my previous post but you had already responded.
Title: Re: Longer array and narrower beam
Post by: Rickard on January 03, 2011, 03:02:05 AM
Bob,

Your question does not mean you are hijacking the thread, it is fully justified! I might add that the only really disastrous type of error is displacement of the array halves across the direction of travel. A displacement of half a wavelength, about 1.6 mm at 455 kHz, eliminates the main lobe completely and the instrument can only show echoes from side lobes, that is ghost images! Other positional errors do not kill the main lobe, but the side lobes become unnecessarily strong.

Regards,
Rickard
Title: Re: Longer array and narrower beam
Post by: keizerh on January 03, 2011, 05:01:21 AM
Rickard,

little off topic, but have you seen this

http://www.drdepth.se/rdthree.php?l=gb (http://www.drdepth.se/rdthree.php?l=gb)

hendrik
(http://www.drdepth.se/images_cc/spinscan.png)


Title: Re: Longer array and narrower beam
Post by: Rickard on January 03, 2011, 06:14:27 AM
Hendrik,

Yes, I'm aware of Per's 'radar' add-on to DrDepth. It will be a very nice feature I think. I'm curious to see what hardware he will recommend, how hardware and program is synchronized and how it will perform in deep waters. Stable rotation that is controlled from the surface is hard to achieve when distance between surface and transducer is long. You have probably read about Juha's and my solution with a heavy transducer that hangs in the cable and where constant rotation is accomplished by the inertia in a heavy transducer. Radar images can be produced back home with some cutting and image transformation, for free  ;)

But this is another topic and deserves it's own thread, I think.

Regards,
Rickard
Title: Re: Longer array and narrower beam
Post by: abraquelebout on January 04, 2011, 11:49:26 AM
hi
two picture of transducer in x-ray
i don't know if its's help you rickard but i you want, i send you original picture by post office[attachment=1][attachment=2]
Title: Re: Longer array and narrower beam
Post by: Rickard on January 04, 2011, 12:07:34 PM
Thanks a lot Abra!

Very interesting. It's not possible to tell how many elements there are in an array, but it struck me that's what one could expect because the arrays are covered with a copper shield that stops the x-rays. I will analyze the positions and check if they vary like they do in my transducers. Let's hope HB doesn't send the police for you because of espionage!  :)

Thanks again
Rickard
Title: Re: Longer array and narrower beam
Post by: Jolly Roger on January 04, 2011, 12:09:00 PM
Wow Abra,

beautiful pictures!!
Are they made from different perspectives (from underneath and above)?

They are really detailed. Excellent work!

Best regards / Harry
Title: Re: Longer array and narrower beam
Post by: Jolly Roger on January 04, 2011, 12:17:03 PM
Let's hope HB doesn't send the police for you because of espionage!  :)

Thanks again
Rickard

I don't think so Rickard.
Abra can for sure proof that it was a case of medical emergency to x-ray the transducer. Even I can identify the life threatening cut on the right / left side of the pictures. Abra had to make sure that there are no internal damages caused by the cut.  ;)

Best regards / (Doctor) Harry
Title: Re: Longer array and narrower beam
Post by: drpelle on January 04, 2011, 04:23:53 PM
For piezo elements, look here:

http://ferroperm-piezo.com/ (http://ferroperm-piezo.com/)


Per
www.drdepth.se (http://www.drdepth.se)
Title: Re: Longer array and narrower beam
Post by: abraquelebout on January 04, 2011, 05:57:05 PM
now i find this
http://www.neptune-sonar.co.uk/wp/index.php/news/ (http://www.neptune-sonar.co.uk/wp/index.php/news/)
whe burn ,??
Title: Re: Longer array and narrower beam
Post by: Humminbird_Greg on January 04, 2011, 07:05:44 PM
Wow Abra,

beautiful pictures!!
Are they made from different perspectives (from underneath and above)?

They are really detailed. Excellent work!

Best regards / Harry

Harry,
They look like different perspectives to me.  Look at the wires going to the temperature sensor at the bottom of each picture; they are reversed.  I’ll make a guess that the top image was taken from the bottom of the transducer as it looks like the wires from the Si elements pass between us and the ‘ears’ of the top transducer housing.

I just think that he will have a hard time getting his insurance company to pay for the x-rays!

Title: Re: Longer array and narrower beam
Post by: Jolly Roger on January 05, 2011, 04:41:44 AM
Now that you mentioned it Greg, it's actually easy to distinguish which picture was taken from above. The first picture, because it shows the cable is going out from the transducer on the right side. Unless the photo is from transparent nature and turned rearside up when Abra made the photo to post it.....

Regards / Harry

Title: Re: Longer array and narrower beam
Post by: Humminbird_Greg on January 05, 2011, 11:13:59 AM
Hmmm, didn’t think about the cable exit hole from the housing location Harry.  Good catch there.  So unless the image got reversed somehow, the top image would be from the top of the transducer and the second from the bottom.  I guess that due to the nature of x-rays and the settings used, that the ‘ears’ on the upper housing of the transducer appear more transparent and seem to be behind the wires used to connect the elements in the first picture, instead of in front of the wires where they really are.  I might have to get a transducer and see if they will let me play with our x-ray machine!

Title: Re: Longer array and narrower beam
Post by: sonar2000 on January 05, 2011, 12:09:20 PM
Shoot.  you work for them.  they should give you a dozen ducers and color x-ray..... ;D... ;).... :P... >:D

Insurance should pay for the x-ray.  Looks like a classic case of sonaritis to me...
Chuck
Title: Re: Longer array and narrower beam
Post by: abraquelebout on January 05, 2011, 04:35:44 PM
 :)waiting rickard news
just for fun
how to make an x ray of transducer and escape to police for espionage :D[attachment=1]
Title: Re: Longer array and narrower beam
Post by: sonar2000 on January 05, 2011, 05:05:00 PM
Very good.  Looks like a new idea for a towfish....... :P
Chuck
Title: Re: Longer array and narrower beam
Post by: Rickard on January 08, 2011, 10:04:37 AM
:)waiting rickard news

I have been busy with other things for a few days, so I had to shelve this project for a while  >:(. The sidescan arrays in the X-rayed transducer are parallel and approximately at the same position in the longitudinal direction. But both arrays are pointed at a small angle from that direction. This is easy to see if one inspects the spacings between the ends of the arrays and the closest edges of the housing. I don't think these deviations have any effect at all on the performance of the transducer. In theory, there could be some effect of varying thickness of the matching layer between piezo and water. The 1 mm cork-insulation, plus the copper foil shield makes it difficult to get precise measures of the piezo arrays.

But Abra's transducer confirms what I found in my transducers, internal positions do not parallel with the outer shape of the transducer, thus making it very difficult to join two transducers. I think I have to expose the front ends of all arrays to assess the exact positions before I can line up the arrays on one side to get one good, long array.

Rickard
Title: The doubleducer is operating.
Post by: Rickard on January 21, 2011, 05:44:45 AM
At last,

the long transducer is ready and tested. I had to concentrate on right SI channel to secure best possible performance in at least one of the channels. I have no control on the internal configuration in the left channel, but the images in that channel are surprisingly good. To get a perfectly(?) straight right array I had to make the doubleducer slightly bent in the horizontal plane and in the vertical plane. The deviations are rather small, about one mm from what would be at the ends if the doubleducer had been lined up only from the shape of the housings.

A doubleducer operated at 455 kHz will, in theory, have the same beam width as a standard transducer operated at 910 kHz. A doubleducer operated at 262 kHz will perform like a standard transducer at 524 kHz.

I tested the doubleducer by doing ice-scanning with the hanging heavy transducer method the other night. Depth at the location is 6 m and transducer was located 3 m above the seafloor. Targets are two small boats near a rocky shore. The individual transducers were connected with their original cables to a homemade connector box in parallel. A 3 m extention was used between the box and the unit. The radius in the images is 20 m (60 ft). Image properties like brightness and contrast are as they were when the images came out after being processed in SiView with color set to blue. There is no slant range correction because the wrecks are so close the transducer.

It's hard to see any large improvement between a normal transducer and the doubleducer at 455 kHz. The big difference appears at 262 kHz. This means 262 kHz can be used instead of 455 kHz to get much longer range and to compensate for signal loss in a long cable application, like when using a towfish at large depth. Careful examination shows the doubleducer when operated at 262 kHz has better resolution than a standard transducer at 455 kHz.

The uncontrolled left channel performs well which means it's easier than I thought to succeed with a doubleducer.

I must add that ice-scanning in shallow waters is difficult. There will always be interference from secondary reflections from the ice that blurrs the images at exactly twice the depth from the center of the image. In this case all the images are rather fuzzy 12 m from the center, making it more difficult to see the differences between the images.

Regards

Rickard

PS As usual, it's almost impossible to attach multiple images.

The Doubleducer
[attachment=1]


The Doubleducer at 262 kHz, right channel.
[attachment=2]


Standard transducer at 262 kHz.
[attachment=3]


The Doubleducer at 455 kHz, right channel.
[attachment=4]



Standard transducer at 455 kHz.
[attachment=5]
Title: Re: Longer array and narrower beam
Post by: abraquelebout on January 21, 2011, 01:49:46 PM
hello rickard
congratulation
it's nice to publy you result
if i compare the picture, the double may give more contrast and accentuatution of detail
in 262 and 455 khz
you make an opposite mounting transducer, is there a reason ?
as the mounting of two tranducer in a same way on a aluminium barr for sample must give the same result ?
what is the sounder to generate 262 khz. ?
i think to find large contemporain wreek  262 khz it's good solution
i see if it's possible to have 2 transducer and mounting has i said  before (same direction on a bar, connecting 2 side and with luck geting best picture in 455 an 800)

Title: Re: Longer array and narrower beam
Post by: Rickard on January 21, 2011, 02:09:23 PM
Hi Abra, and thanks!

Yes, there is a reason for joining the rear ends, the piezoelectric elements must be close, not more than a mm. That's why I had to cut away some material and this was not possible to do in the front end because of the wires.

If you arrange two transducers in a row without cutting away some of the transducer housings the piezos will come too far apart which will cause very strong sidelobes and ghost images. I have done such testings in the past with quadrabeam transducers and have seen the impact of ghost images. But please try it, it's very interesting to see the results and it won't cost much work or money (if you already have the transducers).

I have a 981 model and use transducer XHS 9 SI 160 T.
I'm very happy with the good performance at 262 kHz. This can, perhaps, make it possible to use much longer cables than those we use today.

Rickard
Title: Re: Longer array and narrower beam
Post by: RGecy on January 21, 2011, 05:36:47 PM
Rickard,

Fantastic job.  I know just enough about piezo elements and potting transducers to get me in trouble.  But how hard do you think it would be to build your own elements with longer array.  Basically I was looking to build a custom towfish with 200khz tranducer for depth and and a longer 455khz element for better detail with the increased range the 455khz offers.

Any thoughts?

Robert
Title: Re: Longer array and narrower beam
Post by: Rickard on January 21, 2011, 06:20:14 PM
Robert,

Thanks, after the rather successful doubleducer project I feel it's realistic to make ones own transducer. Late Sture Hultqvist, who presented his methods ten years ago on the Geotech forum, used rather simple methods to build very successful arrays. I remember he used to make "epoxy-bars", which means he mixed as much cork crumbs he could with epoxy and potted the elements in that mixture. It seems as if you don't have to be very precise when building an array, just stay within 1/4 of a wavelength and things will be ok. The problem with making arrays doesn't have to do with the methods, prices for small amounts of elements is the main problem. Another problem is lack of standard elements with correct dimensions. After some research I was adviced to buy transducers and retrieve elements from them, this is the cheapest way they said.

I'm very suspicious about the design of HB:s transducers. They shoot sound through epoxy, a thin copper layer and PVC, and the thickness of those layers varies uncontrolled along the arrays. This must deteriorate the signal because of refraction, attenuation, reflections and standing waves. Sture's arrays had just one layer with calibrated epoxy. The professional arrays have a single layer with urethane. Perhaps I should cut away the outer layer with PVC?  :-\

Added: There is no point in making the arrays extremely long. The nearfield will be wide, but maximum range will not become longer. A too long array will actually have less horizontal resolution than a much shorter array. I decided to not making my transducer longer than two lengths of a standard transducer. Three transducer will result in a more than 10 m wide nearfield with low resolution.

Rickard
Title: Re: Longer array and narrower beam
Post by: Jolly Roger on January 21, 2011, 07:20:20 PM
Great job Rickard, congratulations!!

Do you plan to use the transducer by towing as well? Or is this one only for your "static" pictures?

Best regards / Harry
Title: Re: Longer array and narrower beam
Post by: Rickard on January 21, 2011, 08:50:30 PM
Thanks Harry!

Yes, I plan to use it on my towfish next season and I will soon connect a 50 m cable to it for ice-scanning as well. I also have to check for leakage before I relax...

Rickard
Title: Re: Longer array and narrower beam
Post by: Rickard on January 29, 2011, 02:26:05 PM
Second setback

Transducer #2, the one with right piezo very close the inner wall of the housing (see photo above), seems to have a short circuit in the right SI channel. I noticed this when I cut the cable and checked resistance between shield/drain wire and the ground wires in the SI circuits. There is no problem with left SI circuit and no problems with the SI circuits in transducer #1. Luckily, right channel in transducer #2 is used in the left array in the Doubleducer which already has other defects. This short circuit is not important when the transducer is used with it's original cable, but can have a negative effect when a long extension is used (unbalanced twisted pairs). The short circuit is probably caused by a fault in manufacturing and I think there is contact between piezo and copper shield inside the housing. Since all grounds are joined in the same connector pin, there is no way to detect this type of defect without cutting the cable, as far as I know.

Rickard
Title: Re: Longer array and narrower beam
Post by: abraquelebout on January 29, 2011, 05:32:07 PM
By measuring the connector with an ohm meter i hope whe can detect default of si
the only diference  is made by the thermocouple and if the cable have default ?
if you look the xray picture, all ground sim's going in same conductor.
if i find money i would take transducer and with Milling machine and coat after coats i must take over the two array
i'm dreaming ::)
last week i find concentration of roman column in river
good job for towfish, the archéologist are enjoy...me to
Title: Re: Longer array and narrower beam
Post by: sonar2000 on January 29, 2011, 05:45:33 PM
Since HB does not build the transducer parts but only assemble.  I am wondering why we cant buy the parts separately from the manufacturer as does HB.........
I also wonder how we find out who makes these parts....
Maybe we sould buy the transducer from HB and tell them we do not want it assembled.... 8)
Chuck
Title: Re: Longer array and narrower beam
Post by: Rickard on February 04, 2011, 05:03:45 PM
If I had a unit with 800 kHz capability I would be tempted trying with a Doubleducer with a SI transducer (262 & 455 kHz) and a HDSI transducer (455 & 800 kHz). Such a transducer could be operated at 262, 455 and 800 kHz. At 262 and 800 kHz the beam would be like in a standard transducer, but at 455 kHz the beam would be almost as good as in a Doubleducer with only SI or HDSI transducers (different shapes of sound windows will cause some extra contamination from sidelobes in a mixed Doubleducer). The cost is the same as for two separate transducers, but one would have extended functionality and less need for space for mounting. There would be no need for two cables or a switch.

Someone who wants to try...?

Rickard

Title: Re: Longer array and narrower beam
Post by: Jolly Roger on February 04, 2011, 05:30:53 PM
Hm, not that I want to try to make a combined transducer like yours Rickard. It would be a bit over my capabilities  ???.
But I was thinking of mounting a regular SI transducer and a HDSI transducer to my fish, when I have one of the newer units (997,998, 1197 or 1198).
My plan was to use two switches then: One switch for choosing between the fish and the transom mounted transducer, the second for choosing between the the Si and the HDSI transducer of the fish.
Of course there would be a second extended cable necessary for the fish, which would give more up drift to the towing cable. But with a decent depressor wing to fight that, I guess it would be doable.


Regards / Harry
Title: Re: Longer array and narrower beam
Post by: abraquelebout on February 05, 2011, 05:04:44 AM
in begining with the 1197 unit i take a transducer like this
[attachment=1]
i conect it, 83 - 200 no problem
455 khz no problem
800 khz, bad picture, nothing
i read the doc of the transducer: it work in 83-200 and 455 khz not 800
if you take a 455 transducer and you want to work at 800 it's not possible
i think that a 455/800 khz must work with 262
and i see x ray picture a long time, rickard you've got the better solution with double transducer
Title: Re: Longer array and narrower beam
Post by: Jolly Roger on February 05, 2011, 07:36:26 AM
?? Now you confuse me Abra.

What sort of transducer is this? Is this a break through transducer for a 700 model?

If so, it would make sense, but if it is a break through transducer for the 900 or 1100 models, it should be working with 800 kHz too.

If you want to operate the fish with 262 kHz, you have to use the "old" SI transducer of the 981 and 987 models. These were operating with 455 and 262 kHz only. The newer HDSI transducers (HD stands for High Definition) are operating with 455 and 800 kHz.

You can use the old SI transducer with the 997, 998, 1197 or 1198, because there you can choose in the sonar menu what transducer you want to use.

Regards / Harry
Title: Re: Longer array and narrower beam
Post by: abraquelebout on February 05, 2011, 09:25:53 AM
no, it's the transducer sell with the 1197 to make a hull mounting
http://www.navicom.fr/plaisance/sondeurs/accessoire-sondeurs/sondes/sonde-traversante-plastique-side-imaging-xpth-9-hdsi180t#specifications (http://www.navicom.fr/plaisance/sondeurs/accessoire-sondeurs/sondes/sonde-traversante-plastique-side-imaging-xpth-9-hdsi180t#specifications)
they sel us with the 1197 then if you read specification it's 83/200/455 (scandalous)
when you put the 1197 in 800 khz there's no good picture
i think the anciant transducer can't work in 800 khz
for 262, the 1197 don't work with this frequence ?
Title: Re: Longer array and narrower beam
Post by: Jolly Roger on February 05, 2011, 11:27:57 AM
The 1197 will work with the 262 kHz frequency Abra.
You just have to choose SI transducer in the sonar menu. Of course you would have to get a SI transducer like that:

http://store.humminbird.com/products/313990/XHS_9_SI_160_T (http://store.humminbird.com/products/313990/XHS_9_SI_160_T)

or this one:

http://store.humminbird.com/products/307279?product_id=330d7d7d1ff0c7841b36300f5d1c5a53 (http://store.humminbird.com/products/307279?product_id=330d7d7d1ff0c7841b36300f5d1c5a53)

Wait a second: I was just looking at the site you linked Abra. This looks like an old transducer, because the description states that it should be working with the 981 and the 987. If so, it should be possible to use 262 kHz. Have you tried to use 262 kHz already?

Regards / Harry
Title: Re: Longer array and narrower beam
Post by: RGecy on February 05, 2011, 12:42:26 PM
Yes, it sounds like you got the older 262/455 version  instead of the 455/800.

Robert
Title: Re: Longer array and narrower beam
Post by: abraquelebout on February 05, 2011, 05:17:50 PM
i never use the 262 khz :-X
when i go on the SI capteur menu in my unit there's only 455 or 800
but if whe work with transducer  old and new to get 262/455/800 whe must use different way or conductor whith splitter because 800 khz in 455 transducer make very bad picture
in ethernet cable it's possible because there's lot of conductors, in mine there's only 5
i imagine 2 transducer, anciant with 262 and new wiith 455/800
when you want 262 you make a comutation an other to have 455/800
it's possible with 7 conductor cable
interesting idea
Title: Re: Longer array and narrower beam
Post by: Rickard on February 05, 2011, 07:04:09 PM
262, 455 and 800 kHz are transmitted through the same wires. No need for splitting frequencies on several wires. Harry must use a switch and two cables when using a SI and an HDSI on the towfish.  If he uses one cable and just split it close the transducers, 262 and 800 kHz will work as usual, but 455 kHz will be severely distorted because both transducers will transmit and receive while being too far apart. The 1/4 of a wavelength rule will be violated and ghost images will ruin the image.

I was out ice scanning all day with the Doubleducer and got nice results. But there is an issue with some type of interference that looks like hundreds of tiny bicycle wheel spokes in the radar images. This is not a big problem, but it's difficult to explain and find remedies. It seems as it's time dependent which indicates that it's some kind of system effect. Cable length, two transducers in parallel, the automatic algorithms which control ping rate, pulse length, transmit effect, bandwidth and sensitivity inside the unit etc, many possible sources for this. Next time out I will try with manual settings for most things and see what happens.

Once again I found how useful 262 kHz is when scanning with the Doubleducer at longer range for overview. I use 50 m with ethernet cable and cannot see any significant difference in sensitivity at all from using a standard transducer with the original 6 m cable. The Doubleducer seems to compensate to some extent for the long cable.

Harry, please, don't pretend being stupid! Making a double or triple or whatever ducer is really quite simple and I have seen glimpses from your workshop!  :)

Rickard

Some, perhaps all, of the HB units can be operated at any frequency from 800 kHz and below, ...provided you know which capacitors you need to add/exchange.... :-X :-\
Title: Re: Longer array and narrower beam
Post by: Jolly Roger on February 06, 2011, 03:44:33 AM
Harry, please, don't pretend being stupid! Making a double or triple or whatever ducer is really quite simple and I have seen glimpses from your workshop!  :)

Rickard

Some, perhaps all, of the HB units can be operated at any frequency from 800 kHz and below, ...provided you know which capacitors you need to add/exchange.... :-X :-\

Thanks for your compliment Rickard, I'm honored when it comes from you!
Getting the mechanical part done is something I would trust myself to do. But the electronics / electrical side is giving me headaches. There I don't have the necessary back ground and actually the basic knowledge is mostly missing. It's more then 30 years now when I heard such stuff in Physics at school (if I way listening at all at the time  :-\).

I'll be gone for the next two weeks for a course in Northern Germany and will propably not have an access to the Internet, since the course is in some sort of barrack. Behave and stay safe!

Best regards / Harry
Title: Re: Longer array and narrower beam
Post by: abraquelebout on February 06, 2011, 04:10:37 AM
finaly next project for me : construct a doubleducer with 2 hdsi transducer in the same method of rickard
the only problem is connecting the reverse right an left array in the same cable
i hope cuting the two ducer cable, soldering wire in beggining at my 60 m towcable and if it's working well at 100 m of cat 7 ethernet cable.
i must find 600 € to buy 2 transducer
now i'm on moving boxen, i buy a home and i go on this month
rickard you make scan with double ducer again, can you publy some picture ?
Title: Re: Longer array and narrower beam
Post by: Rickard on February 06, 2011, 04:31:43 PM
Abra,

Please be aware it's much harder to succeed with a HDSI transducer because of the high frequency, 800 kHz! If the 1/4 of a wavelength rule shall be obeyed precision must be better than 0.5 mm. But it's a tempting project, if you succeed the beam will be extremely narrow!

Since we have ice here, all testing must be done with rotation scanning. I have a series of images from `Norrahamnsvraket´ in Luleå in north of Sweden. The four images are: standard ducer at 262 kHz, Duobleducer at 262 kHz, standard ducer at 455 kHz and Doubleducer at 455 kHz. Depth is only 5 m so there is interference from ice 10 m from the center. Radius is 20 m. A good way to compare the images is to look at width of shadows. The wider the shadows, the better the image quality.

Standard at 262 kHz
[attachment=1]


Double at 262 kHz
[attachment=2]

Standard at 455 kHz
[attachment=3]

Double at 455 kHz
[attachment=4]
Title: Re: Longer array and narrower beam
Post by: Rickard on February 06, 2011, 05:01:04 PM
Here are two images from yesterday. Only the Doubleducer at 455 kHz. There is one very nice thing with ice scanning, you can scan extremely close the bottom and get very good shadows from small/low structures.

Rickard

No idea what this is..?
[attachment=1]

7 m sailing boat
[attachment=2]


Title: Re: Longer array and narrower beam
Post by: abraquelebout on February 07, 2011, 02:54:07 PM
thank's a lot rickard
wonderfull picture, double transducer give more detail, contrast and definitions image
you said no more than 0.5 mm marge of error for mounting a double hdsi transducter
is 't in position array between one of the other,or in space of them
i hope in position and space ?
0,5 mm , i Think it' possible to make it...
Title: Re: Longer array and narrower beam
Post by: Rickard on February 07, 2011, 04:50:42 PM
Thanks Abra,

The margins are important within one array, left or right. Left and right array do not need to be parallel. I made a quick sketch where I try to indicate the critical locations for the margins. Don't forget this is a three-dimensional problem, but this was not possible to show in this simple sketch.

Rickard

[attachment=1][attachment=2]
Title: Re: Longer array and narrower beam
Post by: PT on February 08, 2011, 04:23:21 PM
Rickard,

Quite remarkable images, a job well done.

I look forward to seeing the sea trials. What distance and depth do you expect to get out of the doubleducer?

Garry Burton has built a single channel fish that operates through a Lowrance sounder. A question. Could someone with a bit of knowledge (not me) aquire their own pezos and build a twin channel fish; and run it through a Humminbird?

Regards

Peter
Title: Re: Longer array and narrower beam
Post by: Rickard on February 08, 2011, 04:58:25 PM
Hi Peter,

I think a regular and a doubleducer will have about the same depth and range performance. I have the impression, but that remains to be verified, that the doubleducer has longer range when a long cable is used.

Sure, it's possible to build a twin channel fish from scratch! In fact, that was my plan B if the doubleducer failed. Then I would pick out the piezos from the HB transducer and build my own arrays. I'm aware of Burton's products and expected he was going to present something for the HB SI-units. I'm not sure he's still in business.

Rickard
Title: Re: Longer array and narrower beam
Post by: abraquelebout on February 09, 2011, 05:02:29 PM
hi rickard
i understand your picture, it's what i think, 0,5 mm in all direction it's not more but i think it's possible
if i lost it in 455 it may be good. i have 2 chances
like this text : We had not said to them that it was impossible, then they made it
Title: Wiring in the Doubleducer
Post by: Rickard on April 15, 2011, 04:24:01 PM
I forgot about posting the wiring diagram of the Doubleducer here, it's been presented only in my profile until now. Anyway, here it is.

Rickard[attachment=1]
Title: Re: Longer array and narrower beam
Post by: PT on April 17, 2011, 08:52:07 AM
Rickard,

Any new images from your Double Ducer?

Regards

Peter
Title: Re: Longer array and narrower beam
Post by: Rickard on April 17, 2011, 06:47:34 PM
Hi Peter,

Yes, I have many, but they are all 'radar images' because of the long winter. I made my last ice-scanning trip today. The sun rapidly makes the 3 ft thick ice layer unreliable and it's time to prepare the boat. I will present some regular images in a few weeks when the ice is gone.

The image is one of the last I got today. Depth is only 12 ft which makes it difficult to avoid secondary returns from the ice. The radius is 150 ft. Frequency 262 kHz (my new favourite frequency due to good range and signal to noise performance). I use 150 ft with ethernet cable because I have prepared the doubleducer for use with my towfish later this season. The wreck is a tug that was scuttled about 80 years ago when the sawmill on the nearby island closed down.

Rickard[attachment=1]


Added: An old image from the same location obtained with a standard transducer at 262 kHz. The Doubleducer performs much better.
[attachment=2]
Title: Re: Longer array and narrower beam
Post by: abraquelebout on April 18, 2011, 05:08:28 PM
hi rickard
nice and iterrestinng picture
the double ducer is the future
now i work in my hobby with achéologist
i joint the picture of an verry old wreck may be 400 after jc
it measure 6 m than 2,10 meter
towfish , 60 m leng cable, 800 khz
the small strait near the wreck are the referenced line in aluminium steel, they are made in 3 cm square bare of aluminium[attachment=1]
i dream of a double 800 khz ducer... ::)
Title: Re: Longer array and narrower beam
Post by: PT on April 20, 2011, 05:50:31 AM
Exciting find Abra,

Keep up the good work.

Peter
Title: Re: Longer array and narrower beam
Post by: Rickard on April 20, 2011, 10:00:44 AM
Thanks Abra,

I wonder if we have such old wrecks in our waters? Perhaps we have, but we still haven't even found any true Swedish ship from the viking era and that was a few hundred years later than when your find sailed. I'll scan and scan until..... Please be content with your system, you have the best results with a long cable this far. No need for a doubleducer with that signal level at 800 kHz!

Rickard
Title: The Doubleducer used with the towfish
Post by: Rickard on May 18, 2011, 03:39:43 PM
At last, ice is gone and water has transformed into a liquid! I have tested the Doubleducer with the towfish and everything works well. I knew quit well from ice-scanning what to expect and the most significant difference from a standard transducer can be seen at 262 kHz. At 455 kHz the difference is visible, but not as striking as at 262 kHz. I post an image from 30 m depth that shows a new find, a sailing boat. First image shows difference in range between 262 (lower part) and 455 kHz (upper part). The silt bottom is visible up to 20 m at 455 kHz and 50 m at 262 kHz. Rocks are visible at at least 100 m at 262 kHz. Thus, 262 kHz gives good resolution and long range and compensates well for the long (50 m) cable. Second image is a closeup of the boat at 455 kHz.

Rickard[attachment=1]
Title: Re: Longer array and narrower beam
Post by: abraquelebout on May 19, 2011, 02:11:57 PM
hi rickard
today 28 °, but there's waves, good time for surfing and not for scanning.
nice and interresting pictures, congratulation for result
whe have the same parameters between 455 and 800 khz
40m range in 455khz, and 17 m in 800 khz
if i have 2 transducer i must make a double duccer.....
good luck for your next survey
now i'm teatching the archeologist subaquatic chief to use towfish because i have my job and i can't go with them to make survey all around france ! :'(
ah, fu... job
Title: Re: Longer array and narrower beam
Post by: Roddy on May 21, 2011, 12:11:43 AM
Richard; Real nice work, Well Done! Enjoy Roddy
Title: Re: Longer array and narrower beam
Post by: abraquelebout on June 08, 2011, 12:55:33 PM
hi rickard
can you tell me what's the range you must get with 262 khz at 5 meter than ground ?
with 455 khz i must take 50 m range but good picture betwen 0 and 35 m
i wonder if  a 262/455/800 must be an ideal solution for us
i don't know if a 898 csi  work with this 3 mode ?
Title: Re: Longer array and narrower beam
Post by: Rickard on June 08, 2011, 01:52:45 PM
Hi abra,

With a towfish altitude at 5 m I don't expect to 'see' more than 50 m at 262 kHz. I can see further at higher altitude, of course. The resolution sets a limit at about 50 m anyway.

I'm not sure either if the combined transducer would provide useful results. In theory, it can though. It's hard to find clues in the manuals for which types of transducer you can use with the various models. In the manuals for the 997 and 1197 models the answer can be read in the section 'Transducer select'. There the old SI transducer that operates at 262/455 kHz is called 'Sidescan', without any further explanation in terms of available frequencies. 262 kHz is not stated in the specifications although it's available in the units. You really have to be a detective to find out about the transducer options in the HB units. Unfortunately, I haven't found anything in the 898 manual that says anything in the direction of 262 kHz capability. I guess this is a perfect question for Greg?

Added: when looking at the display while scanning I can't see more than about 30 m at 262 kHz, but when viewing on a computer the range is 50 m.

Rickard
Title: Re: Longer array and narrower beam
Post by: Humminbird_Greg on June 09, 2011, 09:35:33 AM
All but the 797 and 798 Si units have the 262/455kHz Si sonar option.

Title: Re: Longer array and narrower beam
Post by: Jolly Roger on June 13, 2011, 02:42:17 PM
Rickard,
congratulations to your results! And what a nice find  ;).

Not much to report from the sandbox. Been to Mazaar in the north last week and thought I stumbled into a sauna when got out of the plane. 40° and rising!

Keep us posted and good luck

Regards from the Hindukush / Harry
Title: Warning!!
Post by: Rickard on June 25, 2011, 01:20:50 PM
I ordered two new SI (262/455 kHz) transducers and started to build another Doubleducer. But I found after cutting away the rear parts that the elements are too dislocated. In one transducer the inclination of one SI element is far from the expected 60 degrees (see image). There are also other differences in locations of the elements which makes it impossible to build a Doubleducer with sufficient quality. After this second try I can't recommend this kind of project. I will probably retrieve the elements and build a Doubleducer from scratch at a later time, or put the rear parts back and turn the transducers into what they were.

The statistics are not flattering, two out of four transducers have proven to be defective in a way that presents great issues when making a doubleducer.

Rickard

[attachment=1]
Title: Re: Longer array and narrower beam
Post by: Jolly Roger on June 26, 2011, 02:49:01 PM
That's bad news Rickard and I feel sorry for you. After all the time and money spent.....
I guess, I will have my transducers x-rayed when I'm back home. Maybe some weired pictures will be explained when seeing the results.

Regards from the sandbox / Harry
Title: Re: Longer array and narrower beam
Post by: Rickard on June 26, 2011, 03:42:45 PM
Thanks Harry, but I don't feel downhearted, this presents a new challenge - splitting the transducers and arranging ideal arrays! From the x-rays and the patent images it seems as if the transducers can be cut lengthwise between the SI elements and the circular downward elements. I think this method is healthier for the elements than complete exposure of the elements with help of some solvent. With these free pieces it should be much easier to line them up perfectly. Then they have to be fixated and protected in some way. The downward readings can be supplied by any regular 200 kHz transducer or by one of the elements from a slaughtered transducer, if a new housing can be arranged.

Take care in the sandbox...

Rickard
Title: Re: Longer array and narrower beam
Post by: Sea-Rover on September 10, 2011, 10:48:31 AM
Hi,
has here a couple of test-pictures of my fish, pictures are in the category DIY-Towfisch.
Longer-Array with 2 x SH-B06T of 262kHz Piezzos, fish with 110 m cables
and waterproof plug.
First picture with 455kHz
further Photos 2-8 with 800kHz (262kHz Piezzos)!!

greets
Title: Re: Longer array and narrower beam
Post by: Sea-Rover on September 10, 2011, 10:55:24 AM
Pictures 2 - 8
Title: Re: Longer array and narrower beam
Post by: Rickard on September 10, 2011, 01:32:12 PM
Congratulations Sea-Rover!
Very nice results! I didn't expect that signal level with a 110 m cable, what type of cable do you use? Have you built the transducer from scratch using piezos from a piezo manufacturer? The code SH-B06T is unknown to me. Added: I just found out SH-B06T is the same as the HB XPTH 9 HDSI 180 T transducer.
262 kHz piezos should work at 800 kHz since 3 * 262 = 786, close to 800. 786 is the first overtone in a 262 piezo, but I'm surprised to see the high signal level.
I'm curious to read more about your project!

Rickard
Title: Re: Longer array and narrower beam
Post by: Sea-Rover on September 10, 2011, 03:05:19 PM
Thanks Rickard,
it was a writing-mistake, the Piezos is of the XTH-9SI-160-P.
I send soon a couple of pictures puts in of the manufacture the Transducer.
The backside absorption of the Piezos is very important (Neoprene), but also the stratum-thickness for out- and input of  ultrasonicsignals.
The cable is alpha-byte 6076C.
The plugs are LEMO-Swiss, pressure-party until 200m specifically for Medicine signale, the cable doesn't have any slip rings because loss of the signals.
Rest follows later

Sea-Rover
Title: Re: Longer array and narrower beam
Post by: Rickard on September 10, 2011, 03:48:20 PM
That's how things should be handled, just take what you need and make your own ducer! What do you mean by "slip rings", I don't know what that is? It looks as if you have joined the elements with contact between them, a design that could cause ringing, obviously, it doesn't in this case. I put in a thin sheet with cork between the elements to be sure to avoid ringing.
What material did you use for the sound window (the stratum)? I think you get good results because of several things: high-end cable, perfectly straight element array and optimized sound window. This winter I will.... :-)
Rickard
Title: Re: Longer array and narrower beam
Post by: Rüdiger on September 11, 2011, 06:09:22 AM
Hi Sea-Rover

Congratulation, a very professional job, really "Swish precision".

mvh
Rüdiger
Title: Re: Longer array and narrower beam
Post by: abraquelebout on September 11, 2011, 01:04:10 PM
hi sea rover
good job, lke whe said in france "Je suis scotché !!"
the sh bo6t ducer is a 262 / 455 khz
it's very professional result
Title: Re: Longer array and narrower beam
Post by: Roddy on September 11, 2011, 03:52:48 PM
Nice, top shelf,Enjoy Roddy
Title: Re: Longer array and narrower beam
Post by: Sea-Rover on September 13, 2011, 06:41:37 AM
Hi Roddy, Rüdiger and Rickard,
thank you all for your feedback. For a good device it needs good transducer.
In the drawing all the important points are covered for manufacturing.
Important work is an accurate piezos.
Defective coating on quartz is about repairing with silver conductive paint.
The cables must be of one piece with no breaks with solder, and ample plug the pressure seal.
Will still perform many tests .........


German is not difficult but English is more ........
Title: Re: Longer array and narrower beam
Post by: Sea-Rover on September 13, 2011, 06:57:30 AM
hi abraquelebout ,
you have been unfortunately forgotten above, thank you ....
Title: Re: Longer array and narrower beam
Post by: Rickard on September 13, 2011, 06:59:55 AM
Thanks,
for sharing all these details! I must ask about the first image that shows a "cavity", does it show an air containment in front of an SI element? If that's so, we have one more case with a defective transducer.
Rickard
Title: Re: Longer array and narrower beam
Post by: Sea-Rover on September 13, 2011, 12:59:01 PM
Hi Rickard,

yes that is an air hole, about 3cm long and up to the rear for cable and 2cm.
The second Image is not the same transducer, it was the third. I have dismantled a total of 4 transducer.

I still want to dismantle a solution for those who do not transducer.
Both sides with grinder to grind the surfaces 4mm. Then hand polish and seal.
See the enclosed photo. The acoustic window is then about 2-3mm thick.
Break through towards the end when possible because of poor installation.
The photo is bad do a better tomorrow where the surface looks good.

Slipe ring = rotating electrical connectors
Title: Re: Longer array and narrower beam
Post by: Rickard on September 13, 2011, 05:10:46 PM
Sea-Rover,
I recognize the idea to grind away most of the housing in front of the elements. But I have found the PVC in the housing doesn't stick well to epoxy, at least not to my epoxy. I use urethane for glueing things to the transducers, but I think urethane is difficult to use for the sound window because of the bubbles. They use vacuum chambers to get rid of the bubbles at the sonar factories, but you seem to have some resources so...  How do you optimize the thickness of the epoxy layer for the sound window? Late Sture Hultqvist used an oscilloscope to find the optimal thickness: http://www.geotech1.com/forums/archive/index.php/t-9995.html (http://www.geotech1.com/forums/archive/index.php/t-9995.html)
(I have disassembled four SI transducer and you have done that with four ducers also. Half of those eight ducers have been defective in some way... are we ready for conclusions?)
Rickard
Title: Re: Longer array and narrower beam
Post by: Rüdiger on September 14, 2011, 05:26:40 AM
Hi

Has anybody test to order the piezoparts direct from the manufacturer ?

mvh
Rüdiger
Title: Re: Longer array and narrower beam
Post by: Rickard on September 14, 2011, 09:03:56 AM
Rüdiger,
Yes, I have searched for appropriate elements at several piezo manufacturers, but no, they must be ordered as custom made which means very high prices. I don't know who makes the elements for HB and even if I knew I suspect they wouldn't deliver to other customers because of terms in their contract. I have checked with HB, but they don't sell elements, only complete transducers.
Rickard
Title: Re: Longer array and narrower beam
Post by: abraquelebout on September 16, 2011, 12:28:01 PM
hi rickard
i read again the subject, i see you picture.
i wonder if when you cut the ducer you cut the array too ?

i think that i go to make a double ducer this winter but i don't want to take out all the elements as sea rover do because i haven't machine tool to make aluminium mounting
i see the xray picture again and i have an idea to make a mounting with your solution and adjust the array..........if the ducer are the same and tolerance are good....
Title: Re: Longer array and narrower beam
Post by: Rickard on September 16, 2011, 01:47:17 PM
Hi abra,
I don't cut the piezo elements, I try to cut off the rear end as close the elements as possible without touching them. The elements are very brittle. I think Sea Rover was lucky who could pick out all the elements without breaking any of them. Sea Rover's housings are very advanced, much more advanced than I think is needed. I have read about a method where the elements are potted in a mix with cork crumbs and epoxy. The result is a very strong epoxy bar that acts as housing and sound absorbing back layer at the same time. The sound window must of course be free from cork. This method only requires a way to fixate the elements while the epoxy is hardening. Even the circular downward elements can be treated this way.
I myself is tempted to break up one of my doubleducers and arrange with separate SI arrays using the epoxy bar method because the left side in the doubleducer seems bad. Let's see if there is time for it this winter.
Rickard
Title: Re: Longer array and narrower beam
Post by: Sea-Rover on September 16, 2011, 05:22:33 PM
Hi Rickard,

Hope you can interpret them here or read:
You're right, it is a delicate work to unpack the piezos.
I work with a magnifying glass and the tool Paläontlogie. Break down completely for a transducer I need a good 5 hours. The piezos are not brittle, it's also finally baked Qurz and very hard. I have broken no element. Finally, they must make when sending a lot of energy in motion.

The filler in the PU oscillator is not good as an acoustic window. Is too soft and absorbs the transmission energy. In theory, the transducer reach up to 300 m per side.
The devices block off the record at 120m.
The two big piezos need to transfer the energy with a hammer art by the PU to PVC. Look to the patent document. There it is drawn.

The cost for the production of aluminum containers are approximately in the range of a transducer.
It is easier to process the areas of the transducer.
Title: Re: Longer array and narrower beam
Post by: Sea-Rover on September 16, 2011, 06:07:21 PM
Here is the picture of the polished transducer. The PVC jacket is partially quite gone.
Thus, the transmission energy can be fully gone. detrimental it is very close range because of 5-10 m, the image drowned.
at 800 KHz but it is better already.
This is more detail to identify from the size of 3-6 cm.
Title: Re: Longer array and narrower beam
Post by: abraquelebout on September 17, 2011, 03:49:18 AM
hi sea rover
i resume :
if i wanted using transducer, to optimise the result i must find a good transducer with no air hole, i must polish the pvc jacket, and adjust the element in window of 0,5 mm as rickard said.
in river 800 khz are more important to find ancient site or wreek in archeology
in salt water 800 khz are difficult to use, but double at 455 may give more details.
at 800 khz i never past 15 m range and good result are in 8 m max than ducer
sea rover, do you have sample to compare a polish ducer than other ?
Title: Re: Longer array and narrower beam
Post by: Sea-Rover on September 17, 2011, 01:44:27 PM
Hi Abra,
it is true, you should find the two transducers has no air holes.
you can edit them like Rickard writes. The tolerances have to be met. Photos are in the appendix of the transducer polished and unpolished.
pol = polished
notpol = not polished
455-800 = HDS transducer
455-262 = normal transducer
All images with 110m of cable
Title: Re: Longer array and narrower beam
Post by: Rickard on September 17, 2011, 04:00:14 PM
Sea Rover,
Very interesting! I assume you have seen the defects in two of my transducers. SI elements have left their positions and came in contact with the inner wall of the PVC housing. If you grind down the PVC layer to almost nothing there is risk for exposing the element. I have complained several times on the quality control at the production line for transducers. A nasty argument would be, and I hate to be nasty - the transducers are just element containers >:D ;) . You have to retreive the elements and build your own transducer to be sure about performance.
Rickard
Title: Re: Longer array and narrower beam
Post by: Sea-Rover on September 17, 2011, 05:05:40 PM
The writing is unfortunately not with me so quickly. !! Googel Thank !!!!!!

To expand is a hobby-cutters with diamond head, see my picture.
This makes it possible to work in tenths of a millimeter.
The piezo has to be exposed all around. best original with 2-3 mm filling it. only when the piezo is replaced replace because the rest of PU.
The PU is not firmly connected to the copper and piezos. He can be solved with the finger nail when the layer is very thin. The surface of the piezo never touch with a hard tool. if that happens with silver conductive paint coat again.

I've seen your defects, at these short piezos is of course a gross error. You can instead of aluminum, PVC or PPE take to build a container. Acoustic Swamp is the important background in the piezos and the axial alignment recall exactly.
A refill the holes with unequal PU can not. there is another layer in the PVC and bad for the sound.
Make tomorrow a photo with a broken piezos repair.
Title: Re: Longer array and narrower beam
Post by: abraquelebout on September 20, 2011, 07:43:54 AM
i polished my towfish ducer and i'm waiting this week end to go on river, there's wreck on fiew point, i must compare result on same waypoint and same object....
if there's good result, i think construct a double ducer polished
Title: Re: Longer array and narrower beam
Post by: Rickard on September 20, 2011, 09:36:19 AM
That's good abra, I will follow your testings.
 
Sea-Rover, do you have the exact dimensions of the SI elements? I tried to measure them, but couldn't get precise measures.
Rickard
Title: Re: Longer array and narrower beam
Post by: abraquelebout on September 24, 2011, 04:36:20 PM
hi rickard and sea rover
i polished my towfish ducer and today i go on river to compare same object on same waypoint with the ducer at same depht
i join picture.
i prefere not polished because wood are more visible, i think polished is better for more range and ducer at more distance than ground.
but if there's more distance a small object sim's so smaler than not polished ducer and i think you don't see it
picture are done with towfish 60 m cable and hdsi ducer
Title: Re: Longer array and narrower beam
Post by: abraquelebout on September 24, 2011, 04:47:24 PM
oh i forget this
i have a problem with the left side in 455
i think a wire in left toutch wire ine right...i must reconect the left side in 455
the polished ducer can serve for the future experiment to cut ducer
in finish i get better result with not polished ducer like this in 800 khz
a 700 after jC sunken wreck
Title: Re: Longer array and narrower beam
Post by: Rickard on September 25, 2011, 04:23:03 AM
Abra,
These are worrying observations. I think one should be very careful with the polishing/grinding because of two main reasons: firstly, if you reach the copper shield that is painted to the inside of the PVC layer the ground circuits will get in contact with water so the signal ground voltage level may become zero, secondly, the new wall thickness may equal a value that match the conditions for a standing wave which can result in great loss of energy. The ideal thickness is complicated to find because it should fit two different frequencies (455 and 800 kHz).

I think you have a wiring fault in your left SI channel, but it's difficult to say exactly what fault from the images. It may be a short circuit like the one I found in one of my transducers where the piezo was in contact with the transducer ground shield (the painted shield on the inside of the PVC housing).

Do you have two transducer systems with 60 m with cable or do you have one system that you have polished? If you have one system the not polished and polished testings must have been done on different occasions so there is the possibility for disturbing factors, like different water conditions, which may have differed between the tests, especially in a river. I'm just trying to find alternative explanations to save the polishing theory...
 
Regards,
Rickard
 
Title: Re: Longer array and narrower beam
Post by: abraquelebout on September 25, 2011, 05:19:28 AM
hi rickard
i have just one ducer mounting in 60 m cable, i polished it
for the left side i think a short circuit whith left /right side 455  in cable (the cable stop propeller during a scan on salt water)
i sea some part on my ducer who can make contact in water with ground.
before cuting ducer i make an isolation of it with small epoxy paint.
i thing polished ducer are good for long range and depht.
i'm going to mount a ducer in my repair towfish cable, and mounting first polished ducer isolated on a second cable (20 m) for testing in river.
Title: Re: Longer array and narrower beam
Post by: Sea-Rover on September 25, 2011, 06:03:35 AM
hi abra,
rickard as already said, there can be many causes.
important:
The surface must be accurately and precisely correct angle to be piezoelectric. for these frequencies to the sound window 1.5 mm to 3 mm thick, it is lampda 1 to 1 / 2

the cable is to give first priority, that it has the correct values​​.
falsify the solder something here worth.
the speed through the water, driven up or down, Temparatur, etc. ..

interferences, it can also give the water ........
will soon post a list of self-mad noise sources
Title: Re: Longer array and narrower beam
Post by: Rickard on September 27, 2011, 04:53:28 PM
Sea-Rover,
I suppose you mean Lambda/4? Sound speed in epoxy and in PVC is about 2500 m/s according to a list I found. This gives Lambda/4 = 0.8 mm at 800 kHz, 1.4 mm at 455 kHz and 2.4 mm at 262 kHz. If 800 kHz is sacrificed 2 mm could be a reasonable compromize to optimize sound window thickness for 455 and 262 kHz and it is within your recommended interval. This is what an amatuer like me believes after some browsing... What do you think, is this correct?
Regards,
Rickard
Title: Re: Longer array and narrower beam
Post by: Sea-Rover on September 28, 2011, 07:10:52 AM
hi rickard,

uii,
because the values are not equally determined.
I have slightly different sound values of klein-sonar inc

PVC-P (soft)      80
PVC-U (hard) 2250
Epoxy            2760
PU                 1778
at the beginning of lambda / 4 where attenuation is then built.
otherwise too many signals that are devoted to a troubled image (blurred).
the computational burden too many information to the visual representation
the whole sound window is then to 2-4mm thick.
lambda is approximately 1 / 2.
HB transducers have a two-layer system PU to PVC, respectively. Thermoplastic.
make the sound waves on a second envelope with different curing can, so that a damping or piezzo can also be excited, that is a gain.
a part of the sound is reflected back and is back on the wall reflects the piezzo goes and gives it an extra kick. in theory, but understandable.
for all three frequencies provides a problematic use without compromising testing with much.

I'm building ~Lambden / 4 is reached then layered with epoxy until the attenuation as the image and the resolution.
other variant is: build with the pu damping, then with epoxy to create the lambda.
test and test and measure against.
Title: Re: Longer array and narrower beam
Post by: abraquelebout on September 29, 2011, 01:02:10 PM
in my polished ducer i see the copper shield  painted to the inside of the PVC layer the ground.
[attach=1]
i make an isolation with a PUA varnish
and when i take out all cable i see this (that i supose before)
[attach=2]
i cut cable and re soldering it
next experience these week.....
Title: Re: Longer array and narrower beam
Post by: Rickard on September 29, 2011, 03:48:38 PM
That cable needs some soldering!! A thin layer with varnish should provide sufficient insulation of the copper shield, I believe. I think it's a miracle you get any image at all! Please, show the results of the repairs when you have done your testing.
Rickard
Title: Re: Longer array and narrower beam
Post by: Sea-Rover on September 29, 2011, 05:11:32 PM
hi abra,
Best of all, it again forms a layer of about 2mm and starts grinding again. if the layer is irregular, there are different path lengths in the sound window. this results in a blurred image and irregular.
is one possible result-refraction.
more interesting would be the mounting position of the piezo. if the layer is very moderate but the copper plate is partially comes forward event. a fault in the assembly of HB.
comes from the cable so the transducer or is it the extension?
Title: Re: Longer array and narrower beam
Post by: Sea-Rover on March 02, 2012, 05:43:49 AM
Hope that's readable!

Towfish-3

The fish is finally finished creating and testing.

The longer arrays operating at 262/455kHz very well be, but in more detail at 800kHz, but the image looks a bit coarser. Therefore, I have installed the HD-transducer to obtain a differentiated picture

The two transducers are displaceable in the vertical. This can be adapted to scan the terrain. This makes it possible to 2m from the ground a scan width of about
40m away. In addition, resulting in smaller objects, long shadows, which in turn increases the visibility.
In very steep bank areas, the country-side chair to be set to ~ 5 °, seaward of the corrected ~ 45 ° down.
The effect is understandable upon close inspection of the trigonometric functions.

The length of the cable is currently at 115m. The cable type is the key to the whole thing. It is not worth saving here. Next step is a cable of 230m.

The soldering must be good and clean. A screening of the cable connections
inevitable.
 
My fish weighs 10kg and the cable has a guaranteed tensile strength of ~ 18kg.
The whole thing is operated without carrier truck. A support cable doubles the water resistance
and the fish pulls up. This effect causes the cable length must be doubled.
To draw weight on the cable to be controlled, I've made a tension gauge at the anchorage point. Thus, in the search movement speed after the
Draw weight can be adjusted.
In compliance with the draw weight and a reasonable rate of ~ 3-4.5 km / h, cable breakage is unlikely.

With a moveable suspension arm, the fish in contact with the ground and an obstacle
simply tipping over and sliding. Of course this is not to be in practice. An accurate Drive and the site search methodology adapted is a must.

Until further notice, and have fun with Humminbird.
Title: Re: Longer array and narrower beam
Post by: Roddy on March 02, 2012, 12:29:42 PM
Sea-Rover, How did the tail fins work out in the tow? Roddy
Title: Re: Longer array and narrower beam
Post by: Rüdiger on March 02, 2012, 03:42:06 PM
Hi Sea-Rover

What are the internal transducer wired, do you lead a separate cable for each sensor to the top?

mvh
Rüdiger

You also can reply in German
http://de.groups.yahoo.com/group/SOB-International/ (http://de.groups.yahoo.com/group/SOB-International/)
Title: Re: Longer array and narrower beam
Post by: Sea-Rover on March 02, 2012, 07:21:53 PM
Hi Roddy,
The tail fins are very effective due to their size, roll and yaw goes back to zero. The turn of course must be selected to be slightly more, because the fish is very stable straight. The U-turns must be made outside of the search field and may not be part of the search grid.
The ratio between the length of the fish and the size of the fins results in a very stable position in the water that is the cylinder to the surface is in proportion to each other of from about 1:0.5.
The suspension results from the total weight and the weight in the nose and in their length.
The fish may be on the air, not horizontal 0 °, otherwise it is unstable in water and it comes to roll and yaw. The horizontal position of 0 ° in the water must be produced with the tensile force and the Flow-pressure the fins, this is achieved with this pressure forces the stable position of the fish.

The fish hangs in the air at about 30 degrees to the back, he stands in the water at around 10 °. At minimum trip, about walking pace it is aligned at 0 °.
In my search for small parts and at a resolution of ~ 3cm such a stable position is very important.

The depressor pulls the fish horizontally down. Do not press your nose like a plane, otherwise the sonar signals received by turbulence wrong or faulty.
The tail fins are in front to ~ 3 ° slightly raised, producing a perfect glide to the tow point.
In the first photo you can see very well how to attract positive tail fin forward.

The cable goes in the water is not straight or angled downward, but always in a parabola. The fish depends on the cable.

A little complicated at these few lines.

Bill ......
Title: Re: Longer array and narrower beam
Post by: Roddy on March 03, 2012, 01:31:31 AM
Sea-Rover, Thank for the post back.  Roddy
Title: Re: Longer array and narrower beam
Post by: abraquelebout on March 03, 2012, 03:53:00 AM
hi sea rover
verry nice job
262 / 455 / 800 khz

how are you doing to separe  in use the 262 / 455 khz array and 800 khz ducer

do you  have some pix of the same target in different fréquences
Title: Re: Longer array and narrower beam
Post by: Sea-Rover on March 04, 2012, 06:03:14 PM
Hi Rüdiger, Abra,

I usually look first at 262kHz with the territory. Depending on the size of the object up to 80m wide search. For small parts it's going to 455kHz.
When Long-Array 800kHz resolution is high but unfortunately a bit thin in contrast.
So I've installed a HD transducer.
There are two connectors available with a waterproof seal. The unused connector
Is stowed in the fish.
Therefore, I change the plug rather in favor of a better contrast.
See Photo 1 and 2

The fish has not undergone the test set forth any changes. Therefore, there are the
Photos in this amount, a little further forward on valid resolution.

Later attempts to optimize the arrays for better or 800kHz.
Then there's also back to images

The depression-wing, I have assembled for the benefit of handling fixed. An attachment to the towing arm would be a lot better, because it reacts to any change in speed.
Large velocity steeper angle ...... slow ride flatter angle.
These photos in the previous post.

I'm usually constant at 3.5km / h, therefore, the fixed wing, photo 3

As a control, the allowable tension on the cable, I hooked a pocket balance, photo 4


Needs a good week .........
Title: Re: Longer array and narrower beam
Post by: Rüdiger on March 05, 2012, 08:18:43 AM
Hi Sea-Rover

Thanks for your answer.
What kind of plugs and towingcables you use ?

mvh
Rüdiger
Title: Re: Longer array and narrower beam
Post by: Sea-Rover on March 08, 2012, 08:05:20 AM
Hi Rüdiger,

The cable is a CAT-6 type. Shielded twisted and 3x2Paare. Very good electrical. Values.
Cable diameter is 9mm, without supporting rope.
The connectors are LEMO and are pressure resistant up to 200m
But are relatively expensive, but the electrical properties are worth it.

LEMO S.A. USA, Sweden etc. Goooogeln

Greetings ....
Title: Re: Longer array and narrower beam
Post by: abraquelebout on March 23, 2012, 02:19:06 PM
during a test (polished ducer) i crash the towfish,
i take the ducer and cut it
i find a big difference in cotation between left and right array[attachimg=1]
in this picture whe can see the arrays
[attach=1]
it's an hdsi ducer 455 / 800 khz
impossible to make a double ducer with this difference
i have question for sea rover
what type of epoxy are you using to make your array ?
for this you say 3 mm of epoxy outside the array, it's right ?

Title: Re: Longer array and narrower beam
Post by: abraquelebout on March 23, 2012, 02:21:52 PM
the second picture to see the diffence[attachimg=1] :-\
Title: Re: Longer array and narrower beam
Post by: Rickard on March 23, 2012, 02:37:36 PM
God heavens!
 
This is yet another observation of a terribly bad transducer. Most dissected transducers have been defective beyond what's acceptable.
 

Greg, what do you think, is the production management aware of this?
 
Rickard  >:(
 
PS Today I was made aware a competitor has released a Doubleducer that can be run at 455kHz (and probably other frequencies too). It can most likely be interfaced with any Humminbird SI model with some soldering and a Y-cable arrangement with a downward 200 kHz ducer. A convenient and safe way to get ones own Doubleducer system.
 
Title: Re: Longer array and narrower beam
Post by: Bob B on March 23, 2012, 05:22:34 PM
Rickard,
Do you have more details about the doubleducer source?

I have been concerned about the transducer quality control since I saw your first posts discovering the problems.  The more of these that are cut into, the more we see how bad the problem really is.  I am thinking the only way to determine if you have a good transducer is to cut into it or get it xrayed from serveral different angles.

It looks likely that the reason abraquelebout couldn't see the wreck with his towfish is that he has a bad tranducer to begin with.

It is pretty frustrating that no mattter how good you are at creating towfish or how good your mounting is on your boat, and no matter how good you are at the settings, you may have bad images because of a poor quality transducer!!

Have you emailed any of these pictures to Humminbird customer support?

Title: Re: Longer array and narrower beam
Post by: Rickard on March 23, 2012, 06:09:04 PM
Bob,
 
No I haven't sent any pictures to the support. Perhaps I should contact the management directly? But I believe they know since this forum should be a rather important source for feedback.
 
The product I'm thinking of is the Lowrance LSS2, the transducer, not the control unit and the rest of the system. They have abandoned 800 kHz for the lower 455 kHz and still have at least the same horizontal resolution and longer range in comparison to a standard transducer. This is the opposite strategy to Humminbird's. HB sells "Compact SI" transducers which have even worse resolution performance than the standard SI transducers have. But of course, better performance means higher price, something that must be accepted.
 
Rickard
Title: Re: Longer array and narrower beam
Post by: Bob B on March 23, 2012, 07:12:47 PM
Thanks Rickard....I would be happy with a sindgleducer that I knew was good quality.

I had seen the LSS-2 being advertised but didn't realize it was 455khz only.  Do they still have a dedicated DI element in this one, or is this strictly to get better SI range?  I know the SI range has been a weakness in the LSS-1.

Let us know how it works out if you decide to try one.

P.S.  Just did a little research, and it looks like they still have the dedicated DI, but they don't say a lot about it.  I am wondering if they run the DI at 800kzh and the SI at 455khz to get rid of the interference problem they were having between the 2 elements.  Could always do a little experimenting and splice a Humminbird extension cable to the Lowrance extension cable.  That way the original transducer cable would be intact and the transducer could be sold if it didn't work out.  Haven't been able to find a wiring diagram of the cable yet.
Title: Re: Longer array and narrower beam
Post by: Sea-Rover on March 23, 2012, 08:52:06 PM
Hi Abra,
That does not look good. I think soon there are no transducers are mounted correctly.
You can take the same type of epoxy for the boats.
Resin for polyurethane acoustic windows take.
As on the drawing
greeting
Title: Re: Longer array and narrower beam
Post by: abraquelebout on March 24, 2012, 02:02:38 PM
hi every body
 thanks a lot sea rover
what are you caled "Resin for polyurethane acoustic windows" ?
i think i go on way as you do, making self made array....

to ask something about this cuted ducer, i get it since a verry long time, it make my first towfish, and i find lot of thing with it... it'was a good ducer and work verry well, it's ok for is used as a simple ducer and it's verry bad to trasform it in double, or polished
i must take it is array for a second life.
no i don't tell it's a bad ducer, more good sample in my post are made with it...
Title: Re: Longer array and narrower beam
Post by: Sea-Rover on March 25, 2012, 10:46:20 AM
which was a mistake.
The truth is that:   "shed for the acoustic window with PGB polyurethane resin"
as shown in the drawing...........
Title: Re: Longer array and narrower beam
Post by: Rickard on June 21, 2012, 09:53:59 AM
Thanks Rickard....I would be happy with a sindgleducer that I knew was good quality.

I had seen the LSS-2 being advertised but didn't realize it was 455khz only.  Do they still have a dedicated DI element in this one, or is this strictly to get better SI range?  I know the SI range has been a weakness in the LSS-1.

Let us know how it works out if you decide to try one.

P.S.  Just did a little research, and it looks like they still have the dedicated DI, but they don't say a lot about it.  I am wondering if they run the DI at 800kzh and the SI at 455khz to get rid of the interference problem they were having between the 2 elements.  Could always do a little experimenting and splice a Humminbird extension cable to the Lowrance extension cable.  That way the original transducer cable would be intact and the transducer could be sold if it didn't work out.  Haven't been able to find a wiring diagram of the cable yet.

Bob,
 
or anyone, anything new on wiring in the LSS-2 transducer cable? It really would be interesting to see if the LSS-2 can be used as a doubleducer for the HBs.
 
Rickard
Title: Re: Longer array and narrower beam
Post by: Bob B on June 21, 2012, 05:45:45 PM
Rickard,
I sent an email to Lowrance customer service requesting the pin-out for the Lss-2 transducer......after quite a delay I got a response that said "sorry, but we do not have that information at this time."

I guess it would require buying one and figuring it out.
Title: Re: Longer array and narrower beam
Post by: Rüdiger on June 22, 2012, 03:04:51 AM
Hi Rickard

I have post your question into two other Lowrance forums, hope for positive answers.

mvh
Rüdiger
Title: Re: Longer array and narrower beam
Post by: Rickard on June 22, 2012, 02:58:39 PM
Bob and Rüdiger, thanks,
 
Something tells me.... HB will release a long, "HD", high definition, narrow beam, long range transducer within a year or two.  ;)
 
Rickard
Title: Re: Longer array and narrower beam
Post by: Rickard on June 26, 2012, 02:11:47 PM
Done,
 
I just ordered the LSS-2 transducer and have to wait for two weeks for delivery. In the mean time I will figure out how to disclose the circuits. There are nine pins. The left, right and downward (DI) channels probably have their separate circuits with individual grounds. This could be the case also for the temp channel. The last pin could be a ground pin for a drain wire, perhaps. This is all guesswork and all testing with the unit connected will be quite risky. All I know in advance is the only circuit with less than infinite resistance is the temp channel. I would appreciate any advice on how to proceed with this.
 
Rickard
 
PS The international manual for the LSS-2 states the frequency is 455 kHz, the US manual says it's 455 AND 800 kHz. The LSS-2 is thus probably compatible with all HB units once the interfacing issues are cracked. DS
Title: Re: Longer array and narrower beam
Post by: Jolly Roger on June 26, 2012, 04:28:00 PM
Rickard,
check your e-mail!
Regards/Harry
Title: Re: Longer array and narrower beam
Post by: Bob B on June 26, 2012, 06:42:53 PM

PS The international manual for the LSS-2 states the frequency is 455 kHz, the US manual says it's 455 AND 800 kHz. The LSS-2 is thus probably compatible with all HB units once the interfacing issues are cracked. DS

Rickard, I was wondering if they are using 455khz for the SI and 800khz for their DI to try to prevent the interference the DI causes in the SI beam......couldn't find anything that documents it very well.
Title: Re: Longer array and narrower beam
Post by: xSilmarilSx on June 27, 2012, 03:09:17 AM
Rickard : If you could find a LCR meter, which stand for Inductive-Capacitive-Resistive meter, you should be able to have a reading on the crystal.

Some cheap digital meter can measure capacitance also.
Title: Re: Longer array and narrower beam
Post by: wreckreationaldivers on August 06, 2013, 03:43:05 PM
Hi Rüdiger,

The cable is a CAT-6 type. Shielded twisted and 3x2Paare. Very good electrical. Values.
Cable diameter is 9mm, without supporting rope.
The connectors are LEMO and are pressure resistant up to 200m
But are relatively expensive, but the electrical properties are worth it.

LEMO S.A. USA, Sweden etc. Goooogeln

Greetings ....

Sea-Rover

what type of LEMO plug & sockets are these?

Cheers

Jeff
Title: Re: Longer array and narrower beam
Post by: Sea-Rover on August 07, 2013, 05:42:22 PM
Hi Jeff,
Here are the order number for the LEMO connector:
FFA.3E.307.CLAC90Z and GMA.3B.090.DG
and counterpart
PCA.3E.307.CLLC90Z and GMA.3B.090.DG
Warning: Multipoleconnectors are fitted with hermaphroditic inserts including male and female contacts.
This is for a CAT-6 cable with a diameter of 9mm.
Cable diameters from 3mm to 15mm are possible for this connector.
Close to good assembly to 200m depth. With PUR shed without problems up to 350m.
with greeting
Bill
SimplePortal 2.3.3 © 2008-2010, SimplePortal