View Full Version : Eagle Fishmark 320?

02-09-2006, 04:09 PM

I have this eagle fishmark 320 fish finder...It came with the boat when I purcahsed the boat....The transducer is mounted on the back of the boat by the engine....I don't have the directions/instructions on how to run it...I did find directions/instructions at eagelsonar.com...But, I just want to know what range the fish finder picks up?...Does it show straight under the transducer or does it shoot out at a range?....I would appreciate any help..

Take Care

02-10-2006, 04:24 AM
it should be a 20deg cone angle "Skimmer" transducer. This will give you a cone shaped area of "detection", that will show bottom features within a circle that's about 1/3 as wide as the bottom is deep. Or in other words ... it shows a 7ft circle on the bottom in 21ft of water..10ft circle in 30ft of water ..etc.

Remember - your transducer is sending out a expanding "circle" of sound pulses ... in a cone shape ... towards the bottom. As the boat moves, the leading edge of that circle is the first thing to register on-screen. Your most accurate "picture" will come from the signal in the center of that circle. Your unit is the signal sender/receiver ... basically a computer that translates the signals it receives into pixels on the screen. The computing power of the unit determines how good the picture is ... and the smaller the pixels, the more detailed the picture. The Eagle 320 is a 320x320 pixel unit. That's 320 little squares (pixels) high and 320 wide ... should be a very sharp/accurate picture of things within that cone !! It advertises that you can get 60deg of "detection" by using high sensitivity settings. But, all the accessory transducers listed for it, are all 20deg cone angle. I'd depend more on the 20deg signal idea, myself.
Look here - http://www.eaglegps.com/products/Sonar/FishMark320.htm - for a Manual download, and other info. .......... cp :cool:

David Waters
02-10-2006, 06:29 AM
great information. You put it so even the dumbest like myself can understand!!!!!!!!

THis is the exact finder I have. But, I have some intersting things gonig on. Let me explain. (this feels like "car talk", but about boats)

Ok, frick and frack

first thing is my transducer cable has a nick in it right above the transducer. This is where apparently the guy who owned the boat before me either hit something, or pulled the TM up with the cable under the head of the motor, rubbing the chord on the gator mount. As I am reading my depth finder screne, if my trolling motor is set on constant, like I do when I am slow trolling, the transducer reads perfectly fine. It reads the bottom and structure just fine, but if I turn off the constant and just work it with the on off switch on the foot control, then it reads crazy things and you cant trust it.

I am guessing somehow that this nick in the chord (which I have taped and wrapped) is grounding out or something. But somehow when the motor is ON, the ground works, but when the motor is off, somehow the water effects the transducer. I have ordered another chord, at the cheap price of $85 bucks, almost the cost of a new df.


02-10-2006, 07:21 AM
I done the same thing to my transducer cord and it was acting the same way,i experminted with silicone to seal it before i bought a new transducer and it worked,give it a shot it might save you 85 bucks.

David Waters
02-10-2006, 07:30 AM

02-10-2006, 07:34 AM
Insure the transducer is mounted level, maybe one click up to the back so when you are moving..., it is close to level. Get rid of the cartoon fish. Set sensativity at around 90%. Leave the auto depth. Menu is pretty easy to make grayline and contrast adjustments.

02-10-2006, 03:46 PM
You can go to the Eagle web site and download the eagle LCG's of your choice to your desktop and run them right there. I found it got me familiar with the unit I bought before I even got on the lake with it.

J White
02-10-2006, 05:45 PM
David, I haven't ever looked that close at your boat, but are you powering
your df off the cranking battery? Need to be, if not. Even if you are, if any
power cables are run in the same conduit, or tie-wrapped together, it can
cause interference. About how it acts different on constant vs. momentary-
I have run into that with my Eagle. It's got a auto noise filter that will
turn itself up to hide a constant noise, but when you bump on and off,
it will show crazy stuff on the screen before the auto filter has time to kick
in - just for a split second, long enough to fill the screen with junk signals.
I used to wonder why I could idle across a flat with the outboard and see
no fish, then kill it and keep drifting, all of a sudden start seeing all kinds of
fish - not coincidence! Alternator interference has got the filter "jacked up",
when I kill the motor, it "relaxes", turns down, and starts showing stuff.
Also, if I have a multiple bank battery charger hooked to both cranking and
trolling batteries, any interference will transfer through the battery charger
to the other bank. If anybody don't believe me, try this - in your garage,
turn the df on, and let it run for a minute, then try turning tm on and off,
connecting and disconnecting battery charger leads, etc. Electrical noise will show up as marks on the screen. Maybe I'm splitting hairs, but it's a "peeve" of mine :D
This guy's site has a lot of interesting stuff (to me) on it.

02-10-2006, 06:34 PM
You can go to the Eagle web site and download the eagle LCG's of your choice to your desktop and run them right there. I found it got me familiar with the unit I bought before I even got on the lake with it.

Did the same thing with the 480 I bought. Although the picture in the tutorial was much much clearer I was still able to see what all the functions of all the buttons were which helped familairize me to the unit.