Topic: 997cSI Images and Specifications

[RGecy]

997cSI Images and Specifications

[Humminbird_Greg]

The 997 units now come with the GR50 GPS Receiver.  This started back in about August of 2008.

[Mark Saikaley]

Is the 997 C SIside and down imaging quality as good as the 998?  i have a 997 Csi with the 50 channel GPS and the latest (well as of August 2011) software
Im wondering because I dont seem to get the same structure quality as Ive seen with some other models posted images

[Humminbird_Greg]

It should be.  Try posting some screen snapshots along with the unit settings and boat speed that you used to make them under a new topic in this section of the web site.  I’m sure that many will provide you with some changes to the menu settings that could be used to improve the images you are seeing.  Oh, might want to include a picture or two of how you have the transducer mounted too.

[Mark Saikaley]

okay, I had posted some on the 998 site as I was expressing envy of some of those images but will post some up here as well. I just don't find that I'm getting that much more detail than on my regular 997 sonar images in terms of revealing things which I am unable to resolve definitively on the regular sonar. I mean if I see some structure in the traditional screens and then switch to the side or down image to get a definitive answer I find I am no closer to identifying what I'm looking at. Yet I see evidence of better images on these pages.  also in comparing my images with images shown for the Lowrance images on-line I find mine don't measure up to the Lowrance. So I wondered if the fact they use a separate transducer makes their structure scan superior?

Anyway I will post some different conditions. The speed is displayed on the images, but if not the speed is usually between 1 mph and 3 mph  and I don't think any of the captured images are above 3 mph, if so definitely below 4 mph

I don't have an image of my mount at this time as the boat is in storage but I removed my factory installed Lowrance speed sensor to I could place the 997 transducer in the most ideal location and followed the instruction's exactly for location and installation. It is located on a 17 ft Sylvan expedition sport aluminum boat the recommended distance away and to the "right" of the 115 yamaha outboard. There are no obstructions in the 180 area and the transducer is level and the bottom edge of the boat intersects the transducer at 50% (IE 50% of the transducer is below the bottom of the boat (given there is a very slight angle on the boat bottom and I selected the area with least rivets however there are staggered rivets as well on the boat so I took the best location all factors and recommendations considered.  The other transducer from the factory installed Lowrance is on the opposite side and is a small transducer and is never in use at the same time and I just kept it installed as back up but didn't bother reinstalling the speed sensor as I have GPS speed anyway.  There is nothing else attached to the transom and no other motors other than the main

[Bob B]

One thing I noticed is that your range is anywhere from 110 to 240 feet.

If it is better detail you are looking for, you would benefit by reducing the range.  Most of the "pretty" SI pictures I have seen are 65feet or less.  Everything will appear larger, and show more detail with the range reduced.  If you find something interesting on the longer scan, reduce the range and scan it again....and from different directions for more detail.

[Mark Saikaley]

Thanks will try that next season. What about the down imaging? There are some down image shots in 25 ft of water . Should the down images yield same detail as the side imaging?

[Bob B]

Since the down imaging is derived from the SI data, I would think both would benefit from a reduced range.

[Mark Saikaley]

oh it is eh. I wouldnt have guessed that. I assumed it had to be using the 2d data and just converting it and interpreting it differently.

thanks for that insight. So would this mean that what Im seeing in 2d doesnt cover the same area as the DI ? ie I cant cross reference the terrain when I show 2d and DI side by side or when switching between the two screens?

[Bob B]

The 2d sonar coverage area is a cone shape ....wider for the 83khz and narrower for the 200khz.  The Si/Di is covering a narrow slice, and that is why it can get better detail.
Running both side by side is a good thing...together you can get more information.

I you search a little, there are some very detailed discussions about various beam coverages on this forum that I have seen in the past.

[Mark Saikaley]

Thanks I will search.  Yes Im aware of the two cone sonars sent, but I suspected that the same transducers were also used for the down image beam as I had understood that the side imaging beams didnt cover the area directly below the boat . Therefore I thought one of the 2d beams had to be double purposed? Considering my unit DI was a software add on without any transducer change

I will search for the details as per your advice, thanks again for your help

[Mark Saikaley]

Since the down imaging is derived from the SI data, I would think both would benefit from a reduced range.

BTW, I switched the frequency for my side scan to the higher 800 khz. My posted images are all 455 khz and have been running with that one only. since switching to the higher frequency I am seeing the types of image quality that I had initially anticipated. When I first compared the two frequencies when I first installed the unit, I dont think I was on the right type of water to distinguish any significant difference, but have since compared the frequencies on more interesting bottoms and am much more impressed. The different views between traditional/side/DI/GPS now are so interesting to me I almost want a separate 10" LCD screen for each view simultaneously.

On a side note, I am quite dissapointed that my 997 unit is not compatible with any of the new Ipilot features and the 360 views.  Expecially since I had the option of purchasing the 998 at the time and didnt have any idea of the potential future (now current)drawbacks for compatibility.

[ezfishn]

Only the xx9/xxx9 models and later were provided software upgrades for the newer MinnKota Bluetooth TMs.