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Old 12-30-2017, 01:41 PM   #271
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Re: Bottom Finder Pics

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Originally Posted by Marcus View Post
Curious...was the bottom really that hard or did you have the gain cranked up that much to see the fish?
Marcus, no the gain is tuned way down but I see why you might think otherwise. That's a 1k 25 degree cone chirp 'ducer set up on a separate bottom machine to primarily find fish, not bottom.

It only does as well as it does with bottom details due primarily to the quality of the display.
You would use a more focused tighter beam 'ducer to show better bottom detail and bottom hardness.

Best, Dan
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Old 12-30-2017, 02:14 PM   #272
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Re: Bottom Finder Pics

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Harvester, yeah it's hard to beat those xsv Garmin units. I don't get out past 400' much anymore but there's exotic bottom out to 1000' for sure. I have never spent time in anything past those depths.

Here's a pic of a spot in 950' that really produced. The big pile of fish were ballbats (queen snapper). Too bad it's undiveable!
Exactly what I needed. Thanks. Making me itch. Soon enough. Queen Snappers are the BOMB!. Can't get them unless I run 100 plus miles around here, although they're probably down there locally.
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Old 12-30-2017, 03:03 PM   #273
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Re: Bottom Finder Pics

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Originally Posted by HeadHunter View Post
Marcus, no the gain is tuned way down but I see why you might think otherwise. That's a 1k 25 degree cone chirp 'ducer set up on a separate bottom machine to primarily find fish, not bottom.

It only does as well as it does with bottom details due primarily to the quality of the display.
You would use a more focused tighter beam 'ducer to show better bottom detail and bottom hardness.

Best, Dan
Dan,
Color me confused but as of my current understanding, bottom finder freqs are in the range of 50/200 KHz, approximately. "1k"? is that 1 kHz or did you mean 1000kHz? I can't find search hits on either. Maybe you super secret dive guys are beyond my reproach? Not trying to be an ass, just trying to understand. Tech shit like this is what keeps me awake at night.
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Old 12-30-2017, 03:59 PM   #274
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Re: Bottom Finder Pics

Marcus,1k watt.Power, not freq.
Another benefit of more power is using less gain.
Dan and Kmoose get huge props for helping people with sonar.
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Old 12-30-2017, 04:06 PM   #275
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Re: Bottom Finder Pics

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Marcus,1k watt.Power, not freq.
Another benefit of more power is using less gain.
Dan and Kmoose get huge props for helping people with sonar.
Thanks, 100.
That makes sense...understood. Illuminating the different densities always seemed important to me. Of course, when you're traveling, that isn't the best settings, from my limited understandings, you're just looking for something to dive on. After finding something, you can then hone in on the quarry.
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Old 12-30-2017, 04:28 PM   #276
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Re: Bottom Finder Pics

Tony's right. 1KW power (1000 Watts RMS).

Most older transducers transmitted at either 50khz (LF) or 200khz (HF).

New style 'ducers including Chirp 'ducers can transmit much lower and/or higher.

I run a 200khz traditional 'ducer with a 6 degree cone on a 1KW Koden bottom machine. A narrow cone like my 6 degree gives a tightly focused detail laden picture on my machine. Shows great detail in bottom structure and bottom hardness.

But, this comes with a price because the 6 degree cone only covers roughly 10.8% of your water depth. (.6x180). So basically in 100 feet of water, you get about 11 feet of bottom coverage at maximum depth. Or 5.5 feet on each side of the 'ducer.

This is a great tool for diving as it allows you to accurately "pin down" a hard small spot with great accuracy

My other 'ducer is a chirp 1KW with a fixed 25 degree cone displayed on a Garmin 12" xsv screen(the one in the above picture). Using the same math as above, this would give you about a 45% coverage of your water depth. So in that same 100' of water, you'd get about 45 feet of bottom coverage.

In 300 feet, you'd get 33 feet of coverage on the 6 degree and 135 feet of coverage with the 25 degree.

I use the 25 degree to primarily look for fish show (and to a lesser extent bottom structure) outside what the effective range of the 6 degree can show. It's common for the 25 degree to show desirable results when the 6 degree is blank. You then just tighten 'er up with the 6 degree and you're there.

This doesn't mean everyone should buy a 25 degree 'ducer. It covers so much area that the details will never be as sharp and good as a tighter degree 'ducer. And on a lower quality (less pixels) screen with a lesser processor, a 25 degree can look like a pac man screen.

You can't run them both on the same frequency due to interference, but no worries as the chirp unit can be set on a single frequency of your choosing. Just set it 10-15 khz away from your fixed frequency unit and all should be good.

A 25 degree 'ducer isn't a good fit for all but for the right job, it's an invaluable tool.
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Old 12-31-2017, 08:03 AM   #277
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Re: Bottom Finder Pics

Thought these examples might be helpful...

This is the coverage with a 6 degree 'ducer
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Old 12-31-2017, 08:04 AM   #278
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Re: Bottom Finder Pics

And this is the coverage from a 25 degree 'ducer
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Old 01-22-2018, 06:15 AM   #279
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Re: Bottom Finder Pics

Pic from the shallow MG a few days ago. Check out the water temp!
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Old 01-22-2018, 09:12 AM   #280
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Re: Bottom Finder Pics

You are still only seeing what is below the boat not the complete area of the cone. You will see the fish or wreck that is off the bottom under the transducer. But nothing out to the sides. You will see out to the sides with the newer side view machines.
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Old 01-22-2018, 01:13 PM   #281
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Re: Bottom Finder Pics

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Pic from the shallow MG a few days ago. Check out the water temp!
Did ya'll dive it? What was the show comprised of?
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Old 01-22-2018, 03:28 PM   #282
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Re: Bottom Finder Pics

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Did ya'll dive it? What was the show comprised of?
Mostly Red Snapper with a few Gags and AJ's.
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Old 01-22-2018, 07:12 PM   #283
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Re: Bottom Finder Pics

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Mostly Red Snapper with a few Gags and AJ's.
Thanks. That makes sense. Was the Snapper for the taking? If so, any good sized ones?
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Old 01-23-2018, 06:57 AM   #284
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Re: Bottom Finder Pics

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Pic from the shallow MG a few days ago. Check out the water temp!
That is shallow for the FMG (Florida Middle Grounds). Long ride out to that area. Great show. Is a video coming soon?
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Old 01-23-2018, 07:31 PM   #285
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Re: Bottom Finder Pics

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You are still only seeing what is below the boat not the complete area of the cone. You will see the fish or wreck that is off the bottom under the transducer. But nothing out to the sides. You will see out to the sides with the newer side view machines.
A wider degree cone blends the entire bottom detail the full width of the cone. The narrower the cone the better the detail. Yes, you do see everything in the cone to its full extent. Deeper the water the wider the cone as it is relative to the angle.
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