[TG] [TG11] Axiom/RV-100 - Unclear image

[neegra]

Hello Tom,

Thanks for the thorough response--it is much appreciated.

Quote:How long did it pause for? That's not something I've come across myself. Normally I'd say restricted supply or changing ping-rate because of bottom-lock-loss, but neither of those look like the case in your screenshots.

It is about a 2-3 second hiccup.
It has happened more than once, with different grounds/negative connections (one grounded at console and one a dedicated run from battery). The +12V remains the same on both trials, but going by the restricted comment I may just change it to the dedicated cable run for testing. I can always add a switch later.

Quote:The three vertical streaks in the fishfinder and DV views do look like a sudden increase in background noise level, but there's no way to tell from an image alone whether it's acoustic or electical noise. I think that the increase in noise level is what's giving the appearance of a lot of clutter in the water column on the RV view, but given the range, I'm confident it's not really your own wash. The reason why it's showing to port only is, I expect, that the real signal levels are lower from that side because of the motor.
It'll be good to see what you get on the all-Manual setup when you increase speed like this.

This makes sense. Thanks for the rationalization.
I am eager to hit the water with the fixed settings. I will try to make it happen ASAP, but it may be next week at earliest.

Quote:It's unfortunately hard to avoid this kind of thing with a transom transducer. It's a bit of a compromise between the convenience and cost-saving of the single transducer against the improvement in the image that results from the through-hull split pair, with tilted elements. I always recommend through-hull faired transducers whereever they're feasible, they are just the best for optimum sounder image. Moving the transducer closer to the outboard may (slightly counter-intuitively) help in your system, at the expense of a bit more noise and increased risk of aeration. Make sure it's not putting aerated, turbulent water across the engine intakes though: starving the engine of a clean flow of coolant water isn't cool.

10-4. I would have gone closer to boat center, but I would have had to place the transom saver over a water inlet (first set of pics) to avoid being downstream of an interruption. I can counterbore the plate to clear the cover while still allowing flow if xducer relocation becomes a necessity.

Quote:Because of the shape of the RV beams, the surface clutter and the way the signal processing is done, the bottom image won't come all the way to the 0ft depth line on the screen. Your images look normal for a shoreline (the 'deep' area further out from the shoreline on that side is the sounder's interpretation of having no signals bouncing back from greater range on that side - it thinks there's probably a big drop-off and everything behind that is in 'shadow'.)

Oooh, I got ya. I can definitely make more sense of when I experience this condition and understand the 'why' after the 'drop off'/'shadow' comment. Thanks. Do you think software could net out the depth on the graphical representation for a better visual depiction of the bottom? Or is there a downside to this?

Quote:The Intensity is a little higher than I generally prefer to use, personally, which is saturating some of the bottom echoes and losing some detail there. Other than that, I suspect that you'll see an increase in clarity if you reduce the scroll-rate, and also view in a larger window (a lot of the graininess in your image is just the limited resolution of the LCD in a small window, some of the fish targets in the water column are only 2 or 3 pixels across, for example.) How does it look full-screen?

I am excited to hear this and looking forward to tinkering with the scroll rate. I have not touched the it at all. I figured it was some auto setting as well (newb haha). Awesome.

I will get some full size images on next outing.

Quote:The appearance will change a lot depending on your boat-speed and scroll-rate, amongst other things. The streaks that you're seeing are a function of your very low speed and what I would guess is a fairly high scroll-rate: things are staying in the SV beam for quote a long time and being stretched out in the image. The bright streaks are almost certainly fish targets (nice ones, given the brightness, size and range: go after them!), whilst the 3 or 4 brighter patches with dark shadows behind that show up down in the bottom right (above-right of the Range +) are likely to be mid-water fish or schools that are casting a shadow on the bottom. You can get an idea of their size and height off the bottom from the density and size of the shadow and separation between the shadow and target. All good stuff to be looking out for. We have a championship-winning marlin skipper here in Australia who uses marks very like those when chasing small black-marlin inshore in 30-80m of water. He swears by it: spot a mark like the one half-way up your image, ~70ft out, circle round, hook up.

Wow I missed out! haha I have gone over the images, thanks for the details!

Quote:Does this answer some of your questions?
Regards,
Tom

Thanks for your time Tom, you've been a great help thus far! I will update you with fixed setting images on my next outing so we can further understand.
-Ian