Topic: Real time video from 798 SI

[burnsider]

I new to this Forum and to side-imaging sonar (my new 798 SI unit is still in the post!!). My interest in SI is for scuba diving rather than fishing and I am based in Scotland (still part of the UK!)

Reading around, it is obvious that there is no video output socket on the 798. However, the 798 has a video display (to state the obvious!!), so there is a video signal inside the case. My partner in my diving/side-imaging/magnetometer project is an instrument engineer who is more than capable of extracting the signal and rendering it into a format suitable to drive an external monitor, so I am hoping that someone here can give me some insight as to where best to find a video signal.

This is really just an early thought about a possible future upgrade - I've not even set eyes on the 798 yet, but it would obviously be nice to have a larger display (the budget would not stretch to an 898 or larger, alas ). I fully understand the issues regarding warranty, advisability of wiring new stuff in, etc. I'm not looking for any proprietary information, circuit diagrams, etc, only something like "Pin 6 and Pin 9 on the IC next to the ribbon connector to the screen..." or the like.

Any snippets of information, experiences of success/failure in such attempts, pointers of any sort would be much appreciated

[sonar2000]

A curious question.  What depths are you anticipating to use the unit? Chuck

[burnsider]

To explain, myself and another (also retired ) member of our local scuba diving club recently got a bee in our collective bonnets and decided to start a project to do some surveying and wreckfinding. We started off with a magnetometer (to find steelwork underwater) then decided to go for broke and add in sidescan as well to give us a high-end survey system. Wrecks in the north of Scotland, especially in shallower water, are often broken up and don't necessarily appear as a nice complete hull, more a pile of bits, so the combination of magnetometer to confirm steel and sidescan to get a better look is a good one. We would be looking at surveying down to about 130 feet maximum and probably a good bit shallower most of the time. The magnetometer has a towfish and we might in the future think about putting the transducer on the towfish to get it closer to the bottom.

We have put together a waterproof pc-based (laptop) system to log data from an existing gps and the magnetometer, so we have a nice 12" screen on which to display data (or a separate monitor could be used). The 798 unit gets a good writeup, but I have seen comments that the screen is a bit on the small side to spot small detail, hence my interest in getting video from the 798 (model selected due to budget constraints). The whole video out thing is just an idea at the moment and I hoped that others who might have had similar thoughts or even tried the same thing might put in their 2 cents worth, if only to tell me that it's not worth even thinking about the whole idea.

[sonar2000]

for depths below 50 feet you might consider building a tow fish. The surface transducers are not optimal at the greater depths. An intact boat might show but broken up into bits and pieces will be a bit difficult without the towfish to lower the transducer into the water depths...HB, Lowrance and several others are not considered high end units. Those generally run in the $100.000.00 range. But with time and towfish you will probably get that which you are looking for.  hopefully.  And as you said, the larger video screen will certainly help... Chuck

[burnsider]

Thanks for the insight Chuck.I was thinking that a towfish might be a good idea and as we have one anyway for the magnetometer, the transducer could be slung below it. Am I right in thinking that Ethernet cable would be ok to extend the transducer cable?

Now if I could just win the Lottery, $100,000 for a high-end unit would be no problem.... 

[rnvinc]

Lots of Towfish info here ...

http://forums.sideimagingsoft.com/index.php?board=41.0

Rickie

[sonar2000]

Ethernet should be fine.  Also if you enter towfish in the search box top right on main page.  You will get a lot of towfish help... Chuck