Thread: test compilation

The 798 comes with this xducer...
XNT 9 SI 180 T :: Humminbird

You can trade in the unopened compact xducer for the HDSI xducer here...
XHS 9 HDSI 180 T :: Humminbird

The HDSI xducer has different size 455kHz crystals than the stock in-the-box Compact xducer which can give better quality 455kHz SI images...

The HDSI xducer also has crystals for the 800kHz SI beam but they would not be utilized in the 798 (because the 798 does not have the circuitry needed to use the 800kHz beam ...)

Some say the upgrade to the HDSI xducer improves the image quality of the 455kHz SI image that the 798 uses...

Conversely, some say they see no difference in image quality...

Maybe someone that has upgraded their xducer to the HDSI xducer for their 798 will chime in...

Below is a depiction of the 455kHz SI beam and the 83/200kHz 2d beams that are included with your 798..

The SI sonar beam is in the shape of a thin slice..
The 2d sonar beams are conventional cone shaped...

For the SI ....Each time the unit pings, the unit takes the echo information in that thin slice and plots that echo information on the SI image across the very top of the SI image in a thin line...

The very next ping echo information is plotted at the top of that same SI image... Pushing the previous echo Information down on the image...

It is this pinging, plotting, stacking (of the thin lines of echo information on the image) .... That builds the SI image on the screen...( it is not a camera snapshot of the bottom)...

The DI in the 798 is a computer generated image created from the data received from the Si crystals in the xducer (it will not be as good of a quality image as can be obtained from a unit that has "dedicated DI crystals" in the xducer...

Keep the chart speed matching the boat speed... 1mph=1 chart speed, 2mph=2chart speed...etc...

Set the SI range to a "left and right range" of about 60-70 ft... Less will make structure look bigger - more will make structure look smaller....
You can set the SI to left OR right only to make structure look bigger...

Choose a pallete that is pleasing to your eyes... Your eyes are different than anyone elses...

Take snapshots and recordings and view them at home to study the images for uninterupted learning of image interpretation...

Use the Si sensitivity setting as a brightness control for the SI image ... Different water conditions/bottom compositions will lighten and darken the SI image...

Ask lots of questions... Pm me if need be...

It is possible to take advantage of HB's xducer trade in policy and trade in the SI compact xducer (that comes with the 798) for the HDSI xducer (and pay the difference)...some users see a image quality improvement with the 455kHz crystals in the bigger xducer.... (you willl not be able to take advantage of the 800kHz crystals in the HDSI xducer even with the exchange because the 798 does not have the internal circuitry to read the data from the 800 kHz cryatals)...

Rickie

455kHz SI beam
img]http://i477.photobucket.com/albums/rr134/rnvinc/SI_diagram_3Drendering_480ft2.jpg[/img]


83/200kHz 2d beams
img]http://i477.photobucket.com/albums/rr134/rnvinc/dualbeamPLUS_screenshots1.jpg[/img]

AC to DC converter

Sunforce AC/DC Power Converter:Amazon:Automotive

DSI @ -10db
455 kHz: approximately 70⁰ (side-to-side)
800 kHz: approximately 50⁰ (side-to-side)

IMG]http://i477.photobucket.com/albums/rr134/rnvinc/securedownload.png[/IMG]

The cumulative displacement filter

The Cumulative Displacement Filter

Doug Vahrenberg's instructional videos...

Doug Vahrenberg Humminbird - YouTube

I spider rig contour lines...

Early in the year ... Before the water reaches 55 degrees...I'll be following creek channel ledge contour lines...
When the water reaches 55 degrees.. I'll experiment with contour lines parallel with the bank...

I'll pick a depth I think the fish will be in and stay on that contour line for several hundred yards....
If I don't pick up any fish... I'll move the boat over 2ft deeper or shallower... And either backtrack my previous pass or continue on down the new contour line...

Once I find what depth the fish seem to be targeting... I'll stay on that contour line until the fish quit biting or until I want to move to a different area and start all over...

Spider riggin contour lines gives the benefit of setting the baits on the shallow side of the boat to a certain depth... And setting the baits on the deeper side of the boat to a certain depth and covering several hundred yards of water without constantly adjusting bait depths...

Rickie

I keep the "SI Enhance" window up on my screen anytime I am viewing SI...

This gives the abilitiy to change the "SI Sensitivity" setting without (opaquing out) any other split view that I have up at the time...

I use the SI Sensitivity setting as a "brightness" control for my SI image (as different water conditions/bottom compositions will make the image brighter/darker..)

SI Sensitivity up will brighten the image...
SI Sensitivity down will darken the image...

I frequently change this SI Sensitivity setting as my SI image changes in brightness...

Here is a screenshot of the "SI Enhance" window overlayed onto the SI image... I had to adjust the sensitivity to 19 to get this mud bottom to reflect enough sonar echo to get an acceptable image...

IMG]http://i477.photobucket.com/albums/rr134/rnvinc/020c59aa.jpg[/IMG]

Rickie