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melnic 04-01-2004 04:15 PM

Testing a fishfinder?
Is there a method for testing if a fishfinder/transducer combo is functioning before installing on a boat?
Can I test it on something like in a tub, bucket or maybe a small pond on the end of a stick or something?
Or should I just take a leap of faith?

-Eagle 320 Fishmark-

19Maycraft 04-01-2004 04:38 PM

RE: Testing a fishfinder?
I got a used fishfinder from a friend, and installed the head unit and powered it up, it worked..then I hooked up the transducer and took the boat out then hung the transducer over the side and it worked as well then I took it home and attached it to the transom, it is a $ 300.00 fishfinder and I got it for free, what a lucky day...

melnic 04-01-2004 04:54 PM

RE: Testing a fishfinder?
I've got the boat in the Driveway installing all the other electronics (new boat ) so I was hopping to save a trip since the boat will be on Rack storage at the marina. Maybe I'll find a low bridge :)


Mike Boehler 04-01-2004 05:13 PM

RE: Testing a fishfinder?
I tested mine in the living room. Hook up the transducer and power it up.(I used a 12v converter). If the transducer has a problem it will probably automatically enter simulator mode. If you don't go into simulator I'll bet your ok. I did this so I can learn it in the winter before chasing the real fish around.


melnic 04-01-2004 09:41 PM

RE: Testing a fishfinder?
Well it was easy to tell it was not dead. When I plugged it in, I could both hear and feel the pulses. It actually read the distance to a wood paneling wall. The distance was about 4.5x the actual distance probably due to the reduced transmission of the pulse. After that I put the xducer into a 5 gallon bucket. You could easily hear the pulse and if I held it right, it would read about 2 feet when it was at the top of the bucket. I guess thats as goof of a test as I'll get for now.

jtburf 04-02-2004 06:37 AM

RE: Testing a fishfinder?
I installed and mounted the transducer...While it was in my Driveway!!!(Thanks Marti for the help)... and Being that I'm a good
ways from the water I went and Got a pack of frozen fillets placed them under the boat ... Sure enough it showed fish !!!!!!!!!!!.....John

gibbsb 04-02-2004 12:03 PM

RE: Testing a fishfinder?
Could it read the name on the plastic bag? :grin: You guys crack me up. Thanks for the comic releif.........

jtburf 04-02-2004 12:21 PM

RE: Testing a fishfinder?
Matter of Fact it read ...Snapper 9/2003........John

E Fitzgerald 04-02-2004 02:39 PM

RE: Testing a fishfinder?
Melnic - when you tested and saw that the "distance was about 4.5x the actual distance" it was because the speed of sound in air is about 4.5 x slower than the speed of sound in water. Therefore your sounder "thinks" that the wall is on the other side of the rose bushes,..........

Also, when you test in air, the impedance of the transducer appears different (typically lower) than when the transducer is in water. With this in mind I would not operate a sounder with th transducer out of water for more than a minute or two at a time.

E Fitz

melnic 04-03-2004 07:13 AM

RE: Testing a fishfinder?
I figured that would be the case with the difference in density of air vs water.
Thanks for the info.
Hmm. you'd think that if damaging the transducer out of the water would cause a failure then the manufacturer would mention this?

E Fitzgerald 04-03-2004 02:55 PM

RE: Testing a fishfinder?
Melnic - allow me to clarify my statement - it is actually the output stage of the echosounder that I am worried about. If the sounder is putting out a fixed power and the resistive load presented by the transducer is lower than expected then the sounder will have to flow more current to maintain power output. On most sounders I would expect the output stage to be tolerant of this but some may not,..... better safe than sorry.

In general, transducers are not perfectly efficient when it comes to converting electrical energy into mechanical energy so some heat is generated within all transducers. The transducers with which I am familiar use adhesives, etc and too much heat can soften the adhesives which would temporarily change the elctroacoustic chararcteristics. In extreme heating cases I suppose it could be perminent effect.

E Fitz

vinny f 05-19-2004 08:19 AM

RE: Testing a fishfinder?

YOU AE ONE FUNNY GUY you really cracked me up

vinny f

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