flasher / fish finder interference

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Robtile

Cadet
Joined
May 16, 2002
Messages
17
I just purchased a new boat and I have a Garmin 176C Fishfinder/GPS and a Lowrance 1440 flasher unit. Both transducers are mounted next to each other on a mounting board on the transom.<br /><br />The flasher is going crazy, reading 100 ft. then 60 then 20, back up to 100 ft, etc. I've tried every setting possible, i.e. manual sensitivity (ranging it everywere), low & high noise reduction (I've waived chicken feet over my head and said a prayer), etc. Today, someone told me that he would bet that the fishfinder is interfering with the flasher unit. He said it is not wiring interference but at the transducer level. He said he's seen this before and the only way around it is to turn off the fishfinder when you run the flasher. It's possible I can disable the fishfinder part of the Garmin (presumably eliminating the interference) so I can still use my GPS. If I can't, that's going to stink because I'd like to run the flasher and map at the same time when I'm running high speed.<br /><br />Anyone familar with this problem that can enlighten me?<br /><br />Thanks,<br /><br />Rob
 
Boatist

Boatist

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Apr 22, 2002
Messages
4,552
Re: flasher / fish finder interference

RobTile<br />If they are both on the same frequency it is not going to work. Likely the old lowrance unit runs at 192 Khz and the Garmin is at 200khz. These frequency are too close together and will interfear with each other.<br /><br />Think about what your are trying to do. Each unit sends out sound signals then listens for the echo to come Back. Each unit is going to here the other units sound signal go out and come back.<br /><br />Think of it this way You and your Freind go to a echo chamber. Standing side by side You yell HELLO and wait for the echo, but your friend herd you yell HELLO and also here your echo come back. Then she yells HELLO and waits for the echo to come back. This time you herd her yell HELLO and also here her echo come back. Well that exactly what happends with your Lowrance and Garmin. They here the sound go out and come back and each unit thinks if is from sound they sent so plots that signal you the ploter or flasher. Since the unit are not timed to send out sounds at the same exact time when it here the other signal it plots if from it last ping. That can be very shallow or deep and makes no difference if your in deep water or shallow.<br /><br />Your Garmin right most row of pixels from top to bottom will show the exact same iformation as the lowrance. Plus it keeps a history previous flash to the left of the right most row. So turn off the Lowrance and watch the Garmin's right most row.
 
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Robtile

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May 16, 2002
Messages
17
Re: flasher / fish finder interference

Thanks, Boatist.<br /><br />It does made sense (Probaby why I didn't think of it) !!!<br /><br />I'll check to see if there is a way to shut off the sounder on the Garmin, so I can keep my map up on the GPS and still use my Lowrance Flasher.<br /><br />If not, I'll just have to live without the GPS when running at high speeds using the flahser.
 
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amirm

Petty Officer 2nd Class
Joined
May 7, 2005
Messages
176
Re: flasher / fish finder interference

I am sure there is a way to turn off the sounder. But if there isn't, see if there is a simulator mode. This is a way to play with the sounder without it having a transducer. Not the best way to turn of the transducer but if you have no other option, it may be worth a try.<br /><br />The other option of course, is to unplug the transducer cable from the back of the unit if it is not flush mounted....
 
Boatist

Boatist

Rear Admiral
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Apr 22, 2002
Messages
4,552
Re: flasher / fish finder interference

If it was me I would throw the flasher over board and make a fishing reef out of it. Your garmin sounder will give your the exact same imformation as that flasher. Only real difference is if you blink on take your eye off of it to see what a boat with right of way is doing you can still look back at your garmin sounder and see what was on every flash. It really records every flash you would see on you lowrance flasher then moves that flash one pixel to the left and records the next flash your lowrance would see.<br />Just my opinion.
 
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Robtile

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Joined
May 16, 2002
Messages
17
Re: flasher / fish finder interference

Agreed, but unfortunatly if you have the Garmin up in full-screen map mode, you can't get a depth reading on that screen. You have to split the screen to get the "flasher" up where the depth reading shows, so you effectively cut about 1/3 of map screen off just to see the depth. That kind of stinks.<br /><br />That was the whole intention of utilizing the flahser - so I could have the map up in full screen and get a depth off the lowrance flahser running at high speed. Maybe the better Garmin models (like the 800 color series) will give you a speed in full map mode, but unfortunately the 172C doesn't
 
Boatist

Boatist

Rear Admiral
Joined
Apr 22, 2002
Messages
4,552
Re: flasher / fish finder interference

Robtile<br />Ok I see your problem and understand.<br />I never really tested any unit but I always though when You put unit in full Screen GPS mode it shut off the sounder. I would look in your sounder menu and see if there is a transducer off or transmiter off setting.<br /><br />Call Garmin and ask. A real pain but you could take off the transducer cable. I would ask if it would hurt the unit before doing it.<br /><br />Hope you will come back with what Garmin says and share information.<br /><br />Good Luck.
 
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Robtile

Cadet
Joined
May 16, 2002
Messages
17
Re: flasher / fish finder interference

Boatist, <br /><br />The transducer cable integrated into one plug with the power, so you can't unplug the transducer w/o losing power. However, not to fear....<br /><br />I did find a software option to disable the sounder, so when I go out this weekend I will disable the sounder on the Garmin while running fast in full screen map mode to see if my Lowrance flasher "insanity" is cured. <br /><br />I doubt whether the Garmin unit automatically disables the sounder in full-screen GPS mode otherwise I wouldn't be having the problem I'm having. If manually disabling it solves the problem, that is just fine with me and is a perfectly acceptable 1 second fix. Your input was certainly helpful and I'm about 99% sure that interference is the problem the way the Lowrance is behaving. Feedback I got from another individual with the same problem said that the interference didn't effect the fishfinder, only the flasher, which coincides with my problem.<br /><br />Just to be clear, I have absolutely no complaints about the Garmin - it works really well as both a GPS and fishfinder. I wouldn't discourage anyone from buying a Garmin. I have had three Garmin units (two handheld GPS units as well as aforementioned fishfinder). They all work great and Garmin support is always helpful and courteous. That's the way it should be, but we all know that isn't always the case !<br /><br />I'll report back in on Monday on the results of my experiment.
 
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js361

Seaman
Joined
Apr 17, 2005
Messages
56
Re: flasher / fish finder interference

I get the exact same problem on my finder, & I don't have GPS....any solutions for me?
 
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DangerDan

Petty Officer 1st Class
Joined
May 21, 2005
Messages
260
Re: flasher / fish finder interference

just to ask, is this Lowrance a dual freq. FF?
 
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