Topic: Law enforcement officers train on new Sonar

[RGecy]

RANKIN COUNTY, MS (WLBT) - More than 40 central Mississippi law enforcement officers are training on a new type of Sonar used to find victims in drowning cases.

It's called "Side Imaging Sonar", made by Humminbird, a company that makes fish finders. The system was originally developed to find fish, but when they realized its capability of finding anything on the bottom, they built a version designed to find bodies in drowning cases.

The Mississippi Department of Wildlife, Fisheries and Parks has the units along with several emergency operations agencies. Even some individuals own the units which cost $3,000 each.

The man who teaches how to use the equipment is 46-year-old Mark Gipson of Eufala, Alabama. He is the director of marketing for Humminbird.

"You actually see the bottom, you take a couple different angles, you could see the body crystal clear. When we started doing that, we knew search and rescue was going to be a big part of this," said Gibson.

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[Roddy]

Humm; HB discovers wheel.

[RGecy]

They are the same.  The only difference is that they say Search and Rescue instead of Fishing Unit.  And the SAR units come with a SAR training DVD.  Other than that, no difference.

Humminbird has also said they will come out with a transducer with a longer molded-in low-impedance cable, like 100-150' long for use in building your own towfish.  Not sure if this will be offered as an option with the SAR units or just as an add-on.

Robert

[calli1]

Since I have been a owner of the S I units ( 898 and 1198 now )...I have volunteered to my local County Rescue Unit to respond if needed for a search.  I will be meeting with them next month at their regulare meeting explaining what I have and what it will do.  This is the least I can do for my community.  I hope they never have to call but if they do, I will be there for them.

[RGecy]

No, the beam width wouldnt need to change.  As for the ego thing, I think the underlying issue was they had trouble getting funding for a unit that was labled a "Fishing System".  They had to have some way to justify it being used for SAR to higher up's who wouldnt know what a side scan was if it hit em in the head!

Robert

[Rickard]

It's difficult to tell how the vertical beam widths in the HB transducers relate to other systems because HB use their own standard, they give the -10 dB angle while most other systems are described with the -3 dB angle. The -3 dB angle is always less than the -10 dB angle. I think they present the one-way beam width like most do, but the practical beam width, the socalled two-way beam pattern is even narrower since the beam is formed both on transmit and receive before it is processed and displayed. Consequently, it's hard to tell if the HB transducers really have unusually wide beams, they are probably about as wide as in most systems.

Rickard

[RGecy]

Actually, based on the results we get with the 800khz and typical range of about 3 to 4 times your depth, if anything, I would want to angle the 800khz beam slightly upward to look farther out to the side.

Robert

[sonar2000]

Since the target we are looking for in SAR is typically small we might be more intertested in detail and not distance. For side imaging, even with the tow fish we generally look in a smaller area and then for a more definate target.
Now if it is the titanic, then we can expand the side to side distance.
Chuck