Humminbird Side Imaging Forums

Other Interest => DIY - Side Scan Sonar and towfish => Topic started by: Rickard on July 13, 2015, 01:42:39 PM

Title: The LowBird-2 system
Post by: Rickard on July 13, 2015, 01:42:39 PM
Hi,

Finally, my dream transducer system is finnished. I call it the LowBird-2 because it is composed of a doubleducer with two LSS-2 transducers (this could actually be called an LSS-4 transducer) and one Humminbird transducer. The wiring is similar to the wiring in the Doubleducer and the LowBird.

The LowBird-2 has been tested and it works like predicted. Long range performance is better regarding horizonal resolution. The signal level appears to be about the same as with the "old" LowBird. At short range, up to about 15' the horizontal resolutions is worse than with the LowBird. This is because the length of the transducer (16", 400mm) affects the beamwidth at such range. I can unplug a few wires to make the system behave like a normal Lowbird, though.

The images show the doubled LSS-2 (LSS-4?) from below, the complete system arranged for use with a foldable Porta-Bote and some "Rats nest engineering".

Do I recommend trying this? The answer is.......no....or maybe. The enhancement of the images can only be seen in replay with a computer. The units do not have the pixel resolution needed to benefit from the extra sonar resolution. It was difficult (very) and I managed to cut a wire accidentally. However, it was great fun....

Regards,
Rickard


Title: Re: The LowBird-2 system
Post by: newkid4si on July 13, 2015, 06:56:01 PM
 Rickard

    Congratulations on the success of your transducer project.   Few other posters possess your engineering skills.    It's been a long and interesting trip.

          Mike 
Title: Re: The LowBird-2 system
Post by: abraquelebout on July 14, 2015, 02:19:21 AM
congratulation
it's nice and intersting, Waiting for picture to compare lowbird 1 and 2
i hope you cut the Lss2  and reverse one wiring to seal the 2 ducer :)
Title: Re: The LowBird-2 system
Post by: Rickard on July 14, 2015, 06:11:51 AM
Thanks guys,

I will be back with comparisons between the systems. From what I have seen this far there is no breathtaking difference between the Lowbird-1 and Lowbird-2.

To cure any anxiety caused by the "rats nest" image I will show a wiring diagram on how the connectors are used. This diagram can be used also for making a LowBird-1 system, just omit everything that has to do with the front LSS-2 transducer.

Rickard
Title: Re: The LowBird-2 system
Post by: rnvinc on July 14, 2015, 07:51:26 PM
I like it ... A lot ...

Good work Rickard ... !!!

Rickie
Title: Re: The LowBird-2 system
Post by: Rüdiger on July 16, 2015, 12:42:02 AM
Congratulations

Again a typical work of Dr.Sonar. ;D
Waiting forward to ergleichbare images.

mvh
Rüdiger
Title: Re: The LowBird-2 system
Post by: Rickard on July 21, 2015, 02:24:20 PM
Here comes a few test images from the same locations with the LowBird-1 and the LowBird-2 transducers. I should have used a mosaic software to get as fair comparisons as possible, but the program I have is way too complicated to use. Therefore I use the user-friendly and quick HumViewer.

Adding images is still very difficult in this forum so I just add them together at the end of this post in this order:

1. LowBird-1, range 150'/50m.
2. LowBird-2, range 150'/50m.
3. Lowbird-1, range 60'/20m.
4. LowBird-2, range 60'/20m.

Rickard


Title: Re: The LowBird-2 system
Post by: abraquelebout on July 22, 2015, 01:43:13 AM
hi Rickard
thanks for the first pictures
at this time whe can't see more details between the Lowbird 1 and 2 except in second picture, the resolution is better in 20 at 30 m range.
do you have refmaster viewer ? the screen result with this soft is good.
One thing is sure, the humminbird support a verry long array.
Title: Re: The LowBird-2 system
Post by: Rickard on July 22, 2015, 04:15:03 AM
Thanks,
My eyes see better resolution along the shoreline in the LowBird-2 when comparing the first pictures. I'm looking at the lengths of the detail echoes along track. Long details means worse resolution. But my eyes are very biased at this time....

To demonstrate why no dramatic difference can be expected I made two diagrams which show the main beam at three transducer/array lengths; 4" (Black, Humminbird standard transducer), 8" (Blue, LSS-2/ LowBird-1) and 16" (Red, LowBird-2). The first diagram shows the transmit beams (one-way beams). The second diagram shows the transmit plus receive beams (two-way beams). The two-way beam is narrower than the one-way beam alone because the two-way beam is shaped twice. Frequency is 455 kHz.

(The units show the effect of the two-way beam so the practical beam is usually narrower than the beamwidth stated in the specs for a sonar - which of course is nice. Most sonar manufacturers seem to use the -3dB one-way beamwidth in their specs so most systems are actually better than the manufacturer claims. Humminbird use -10dB one-way beamwidths which is unusual, but gives a good hint on how much is shown on the display in the downward "fishfinding" channel.)

To read beamwidth from the diagrams, select a curve at the top, follow the curve down to the preferred decibel-level (left or right slope doesn't matter). The decibel level is shown on the vertical axis. Read the angle from the horizontal axis at the top and multiply by two.

Rickard
Title: Re: The LowBird-2 system
Post by: newkid4si on July 22, 2015, 06:39:58 AM
Rickard

     I am impressed with your research and explanations. Thank you.

          Mike
Title: Re: The LowBird-2 system
Post by: Rickard on August 16, 2015, 09:15:11 AM
Just in case someone has plans for a LowBird-2 system, the piezo arrays in the transducers should be connected in series for best signal strength. I had issues with low signal, but found the signal gets at least as strong as with a single LSS-2 when I modified the circuits. See the modified wiring diagram.

Rickard
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