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I would be beached if I relied on my JRC FF50!

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I would be beached if I relied on my JRC FF50!

Old 07-19-2004, 10:45 AM
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Default I would be beached if I relied on my JRC FF50!

Hey guys, I have a JRC FF50 on my recently-purchased boat, and the screen is big, brilliant, and simply beautiful. Trouble is that when I'm in shallow water, it's worthless in giving me an accurate depth. It can be pretty unnerving knowing that you're in 4 ft of water, but the darn thing tells you you have 7 ft to play with. That's a big difference when, engines down, my draft is 3 ft. How can it be so wrong when I need it the most? Since this is the first fishfinder I've ever owned, I don't know much about their intricacies (or idiosyncrasies), so some expericienced knowledge would help. Thanks.
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Old 07-19-2004, 10:54 AM
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Default RE: I would be beached if I relied on my JRC FF50!

Most FF's will work from 2 or 3 feet down. They are not very good in shallow water. Make sure your set to the 200Mhtz freq. 50 works better in deep water, 200 works better in shallow water.

One thing to remember though, it is measure the depth of water from the BOTTOM of the boat, not the water line. So if it reads 2', and you have a 2' draft, your probably in 4' of water.
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Old 07-19-2004, 12:12 PM
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Default RE: I would be beached if I relied on my JRC FF50!

Khz Thats pronounce Kilo Hertz.

Not Mhtz Mega Hurtz.
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Old 07-19-2004, 12:19 PM
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Default RE: I would be beached if I relied on my JRC FF50!

when running shallow up the ping rate.
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Old 07-19-2004, 12:21 PM
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Default RE: I would be beached if I relied on my JRC FF50!

agree...make it scroll faster and it should work more effectively in very shallow water...still aint gonna help you if you run out of water, but at least should give you prior warning!
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Old 07-19-2004, 12:27 PM
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Default RE: I would be beached if I relied on my JRC FF50!

I'll look up to see how to increase the scroll (ping) rate. What's "gain"?
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Old 07-19-2004, 01:11 PM
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Default RE: I would be beached if I relied on my JRC FF50!

Sounds like you really need to sit down and read the instrutions.You should be able to set the off set of the draft of your boat.You have alarm warnings that are able to be set.If all else fails,leave it in auto,it will track back down to scale.
Last year,I was heading out a pass of the missisippi river,been that way a 100 times.Well,I had ran aground,yes I was at idle,and my sounder was set.Bad thing is that it didn't read a dam in skinny water,had to have my port prop fixed after dry docking the boat.After that,I had installed a second sounder just for skinny water.It is a garim 160 blue,dam thing reads almost as good as my furno which had set me back $1200.Go figure!
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Old 07-19-2004, 01:12 PM
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Default RE: I would be beached if I relied on my JRC FF50!

gain is how much reurn gets displayed from not a thing to the freeking whole screen is full of crap. It sets the sensitivity of the receiver.
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Old 07-19-2004, 01:19 PM
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Default RE: I would be beached if I relied on my JRC FF50!

Does your unit have an offset setting for depth?
How deep is your transducer....if using a through hull it may be
3' below the surface to start. If so you may be able to adjust
for the difference of sea level and where your transducer is located.
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Old 07-19-2004, 01:54 PM
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Default RE: I would be beached if I relied on my JRC FF50!

Unfortunately, the instruction manual assumes that I know something about fishfinders, which I don't. In any case, I've been able to make enough sense of it to set the draft offset and calibrate a few other things. But nothing that I've done seems to correct the shallow water problem, hence my asking for some hands-on advice. I'll give the scroll speed setting a try...that one's not in the instruction manual.
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Old 07-19-2004, 02:14 PM
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Default RE: I would be beached if I relied on my JRC FF50!

Another thing I find usefull is to turn down the gain when in shallow water...maybe that'll help.

Good Luck! will watch your progress.
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Old 07-19-2004, 02:25 PM
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Default RE: I would be beached if I relied on my JRC FF50!

'preciate it...
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Old 07-19-2004, 02:35 PM
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Default RE: I would be beached if I relied on my JRC FF50!

Sorry if you thing I was bad mouthing you,next time before you leave out on a trip from the landing,take some time and play with it there.It doesn't matter if you are under way or not.If you are underway,and the transducer is picking up air,you will have voids in the feedback on the sounder screen,trim down and slow down till it has clear up and full feedback showing on your screen.
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Old 07-19-2004, 02:57 PM
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Default RE: I would be beached if I relied on my JRC FF50!

Changing the scroll rate will have absolutly no effect on your ability to read shallow and the advice to change the ping rate really only applys if you have one of the newer Lowrance machines, but even there its a silly feature (marketing ploy actually) that really isn't going to improve your performance at all. In short there isn't a thing you can do about the problem with your machine. By the way, the keel offset won't make it work any better either and the transducer doesn't measure depth from the bottom of of your boat, it measures from the bottom of the transducer, which could be placed anywhere.

Thom
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Old 07-19-2004, 03:04 PM
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Default RE: I would be beached if I relied on my JRC FF50!

So what then can I do???? What's causing this problem and how can I can adjust the unit to correct it?
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Old 07-19-2004, 03:37 PM
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Default RE: I would be beached if I relied on my JRC FF50!

Actually, it's MHz as in Mega Hertz, "Mega Hurts" is radio tech for a reallly bad hangover....
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Old 07-19-2004, 03:57 PM
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Default RE: I would be beached if I relied on my JRC FF50!

I wasnt correcting his spelling, just pointing out he had the wrong acronym all together. The correct one is Khz I said!
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Old 07-19-2004, 04:32 PM
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Default RE: I would be beached if I relied on my JRC FF50!

On my Sitex there is a setting for pulse length. Longer pulse length for deeper water. Shorter pulse length for shallow water. My understanding is this. The transducer has to vibrate to send the pulse down into the water and can't listen for a return while making it. Thus in shallow water the pulse bounces off the bottom and gets back really fast so a very short pulse is required. At some specific depth for each sounder the overlap becomes unavoidable so the unit can't read the depth as the pulse has already come back and gone before the unit put its ears on.
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Old 07-19-2004, 04:43 PM
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Default RE: I would be beached if I relied on my JRC FF50!

I had the 500F which is the same FF as your 50FF.

I was able to consistantly read water to about 2.6' on the digital readout.
But I had to turn the gain way down in the shallow water and also reduce the power
output a bit. Sorry I don't remember off the top of my head the key strokes to make that work.

Also another thing that is important is that you run the machine in manual mode. We have a lot of
sandy bottom down here in SW florida. And when I first had the machine in auto mode it would never aquire bottom due to the depth changes and sandy bottom. 600 watts is a lot of power for muddy or sandy bottom
when you are talking depths of less than 10'

So I would try putting it in manual and turn the gain down to start when you are in shallow water. If that doesn't work for you. Get a little deaper into the manual and drop the power down a bit.
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Old 07-19-2004, 05:06 PM
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Default RE: I would be beached if I relied on my JRC FF50!

Great info, sean....I'll give it a try.
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