Side Imaging in 360° ?

Hi All,
For the Futur unit, it is possible to have a "rotative" Beam Transducer ? ( horizontal rotation)
By this way, when the boat is stopped or drifting, we can see a 360° ! like a USS-571 Submarine Sonar Cool

Can you get this on the 797 If so how?

WarrenMN mounted a 997 xducer on a bucket with a handle for rotating while out on ice.

The display showed a standard rectangular side image, but the information would have been what you are describing, a disk of coverage around the location of the xducer.

I'm sure he will explain it better when he sees this thread.

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Float Tube Fishing in Ireland

Hi,

Warren has not shown up but here is his page on rotating sonar: http://www.accuemap.com/Ice_fishing_with_Humminbird_997.html

I have plans for a similar arrangement but need advice on how to transform the rectangular images to something in polar form (like what you see on a radar) in the computer. Programming is too hard for me so I hope there is some software that can do this. Anyone who has ideas?

Rickard

This is related to the rotating sideimaging issue. I have mounted a SI transducer on a broom shaft so I can walk along the shore and scan the areas along the shore without a boat. It works very well and I can "see" up to 70 - 100 meters at 455 kHz. It doesn't matter that it's shallow, the image looks good even if the transducer almost touches the bottom. I use a 7,5 Ah lead battery which has seemed sprightly after 5 hours of use in + 4 degrees Celcius. I must say I'm satisfied with the results. It's rather easy to control a constant speed when the shaft is swept slowly along an arch in the water.

There's one problem though, only one channel is used and this means the other channel could be turned off. Actually, I have covered it with cork to prevent it from screaming towards to shore. At least when I tried the system in a port the hard steel walls reflected the unused channel's sound and caused some interference. I think the cork has fixed this but it would be much better if the channel could be turned off. Is there a way to do this? If not, would it harm the instrument if the wire for the channel is disconnected? My unit is a 981.

Regards
Rickard

Hi,

Seems as I have to promote my idea... I have found a better solution to the shaft issue. I found a telescopic aluminium shaft that can be extended to 4 meters, perfect. Now I can reach the water from high positions and reach by bushes and other obstacles. The universal joint helps when I have to scan "around corners". I put a belt on the unit so I can have it on the chest and the battery is kept in my backpack. Really entertaining to stroll along the shore and scan when I wish. I show some examples below. Each image covers a sector of about 90 degrees. Area close the shore gets very distorted but from 10 meters and beyond the images use to be easy to interpret.

Rickard

System used.

The image below shows a small wreck outside Oskarsvarv in Luleå, Sweden

Next shows a mess of timber close Oskarsvarv.

This is a long range overview from Sundet over Luleå river. Note the timber and the structure of the bottom.

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Last edited by Rickard on Sun Oct 26, 2008 7:28 pm; edited 2 times in total

congratulations Richard ....
VERY best results !
i'am trying that in a few days ....

Thanks Francis, merci,

I look forward seeing your results! This way of scanning means new possibilities. Now I can scan ponds, small rivers, small lakes at places where a boat is impractical or where there is no road for a trailer. I think the system will work fine for scanning under ice during the winter too. Apart from treasure hunting (I'm very childish....) it's possible to get a quick overview of fishing spots in small waters.

I took some more snapshots this evening:

Two small (6 - 7 m) wrecks outside Oskarsvarv in Luleå. (Note the temperature....)

Overview of Luleå river between the pipeline and the bridge to Bergnäset. The pipeline is straight but becomes bent in the image due to distortion caused by turning the transducer almost 180 degrees. (A wish for Christmas - a software update that can display the rotation image as a sector).

Rickard

Are you setting the chart display scroll speed at maximum, and then rotating the xducer as slow as possible?

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Float Tube Fishing in Ireland

	baitboat_dude wrote:
	Are you setting the chart display scroll speed at maximum, and then rotating the xducer as slow as possible?

The setting of scroll speed depends on range and width of the sector I'm scanning. At long range, 70 to 100 meters, ping rate becomes low, scroll speed goes down, and the transducer has to be moved slowly for that reason. Scroll speed is automatically adjusted to range and the manual setting of scroll speed seems to work as a constant that sets the general speed level. Now I use a scroll setting just above the middle of the scale, 6, in most cases. If I scan a narrow sector I can use high scroll speed and have an image with less distortion. This technique definitely require some practice. But experiance comes fast because you can repair your mistakes easily. Just scan the same thing again until you are satisfied. This is much more laborious and time consuming when scanning the usual way from a vessel. When one stands by the water and notes how the image developes as the rod is swept you get info from the image but also from the direction of the rod. This means you see the actual direction to the target on where the rod points and have the distance to the target on the display. In all, that gives a nice feeling of control of what you are doing.

Regards
Rickard

Side scans with a rotating transducer that scans 360 degrees, as well as up and down have been available for decades. They call this a sound dome and the assembly is raised and lowered through the hull. Along with my Hummingbird, I have a Wesmar with this type of sound dome. If Hummingbird were to compete with commercial side scans, you couldn't afford it.

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Capt Kev - M.V.Endeavour

Several different styles of sonar technology are coming together in this thread.

To try to clarify:
The problem in display is that when the transducer is turned, or mounted on a boat that turns .... the side image still comes out as a "straight" rectangular plot on the display screen.

In this particular thread it is suggested that the transducer be rotated 90 degrees or 180 degrees, and the display goes into a "straight" rectangle, you must try to figure out what distortion that will put on a picture of the bottom out in front.

Like your view of the windscreen wiper going back and forth on the windscreen of your vehicle. The layout is obvious to the driver. BUT if you are a fly sitting on the wiper itself, all you see is a distorted view. The big picture would be impossible to figure out, even though you see the exact same information. The rotative distortion is hard to filter into a "map-view-from above" layout.

If the HBird got a software update that allows points in the side image to be plotted in accordance with their GPS location, based on the location of the GPS unit, and the distance away the SI points are relative to this, this problem would be solved. And if a boat was cruising in a curve, the si display would also plot " a curved rectangle" with the true view from above plotted on the display.

This would be a great step forwards IMHO, and the angling market would find si displays easier to understand if this were implemented.

But it would not sort out the situation of this thread, where a transducer is stationery, but rotated. That requires a different but simple software update, so that all si points are plotted on a quadrant screen display, and responsibility falls on the operator as to how fast the transducer is rotated.
A rotating quadrant display could easily be automated if a data exporting NMEA compass is mounted on the transducer, and it's bearing is sent back to the si unit. Quiite do-able. The sonar unit already has the necessary NMEA data importing ability.

In the meantime the dome xducer remains a commercial unit at a commercial cost, and is extremely large for privately owned fishing boats.

Already available in the sub-2500$ cost area most of us operate in, the Interphase alternative has a much less detailed screen.

this uses the same phased array transducer technology as the Humminbird Si units, but the mini transmitters in the array are arranged horizontally so that the si beam "sweeps" that horizontally. Ths produces a radar-type display instead of a photo-like display.
The reduced detail is due to a wider beam, not an inferior tachnology.

The HB SI units have a similar group of mini xducers glued together in an array.

The Humminbird array of mini-xducers is vertical-side oriented, and the xducers emit a narrower beam so as to get more detail

The thin HB 4 degree (?) si beam produced more detailed information, individual fish, rocks, etc. The Interphase wider 12 degree seems more robust in adverse conditions, xducer mounting issues, but produces less detail, and more radar like information. It is a trade-off of features vs technology.

I for one am looking forward to the day when the gap between these two versions of scanning sonar closes and the THIN BEAM forward-side scan becomes a lower cost reality. Maybe next year ...... Very Happy

In the meantime, if Humminbird could get those software add-on functions available, the SI units would be so much more flexible.

Norm

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Float Tube Fishing in Ireland

Curious !!!, no comment from humminbird members ? Wink

I think you guys are doing fine without any comments from the 'peanut gallery'! Laughing

I really like your portable Si scanning rig.

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Greg Walters at Humminbird
gwalters@johnsonoutdoors.com
I help because I can