does anybody have a fish hawk and get interference from their depth finder? My fish hawk will work fine until I put on my depth finder. Then the fish hawk will go crazy. If I put it on the downrigger closest to the fish hawk I fewer problems. Anybody ever have this?

You are most likely experiancing interferance due to both units running on the same or similar frequencys.

A fish hawk runs at 70 khz

Most fishfinders run at either 50 or 200khz.

Some finders run at 66khz or other frequencys, if yours runs in the 70 range this will cause problems with the signals mixing. Sometimes finders running at 50 will interfere but not always.

Read in your fishhawk manual. I think there is a screw on the back next to the calibration screws that may adjust the frequency up or down a bit to get the signals to seperate.

Hope this helps, good luck!

thanks for your help. I have heard that some guys have to get a filter.

are they being powered by the same battery? sometimes that will effect them as well.

Bob YOAdrien is right on the $$ about the freq.issues also make sure that your wires from the fish hawk are all by them self to the battery don't use a common conection and keep the wires away from you fish finder wires If you still have problems you could get a RF choke it's a pc of ferrite that the wires go thru and could help filter out the freq that is giving you problems I can't remember who it was but they posted something about these chokes in a past post.Good luck.

Erin

I have used snap-together chokes on my boat for interference very successfully, Choke.

Gray Ghost How did you know what choke to get Trail and error?

Erin

I don't know how much the chokes will help on this one?
I believe the problem is happening in the water because there are 2 transducers sending signals in close proximity at similar frequencys they are picking up each others signal in the water.

The toriod choke will give you much more attenuation than the ferrite. The ferrite choke is used more for control and data cables and also can be used for power lines. The choke is more effective when installed close to the offending source of the interference.

where do you get these chokes? Do you have to put them all the way down to the transducer or just arrount the units?

Here is a thread concerning the Fishhawk 840 problemsFishhawk 840.
The toroids are available at Radio Shack, click on “Choke”. Put the choke as close to the unit as practical.

Thanks for that usefull information. That should solve my problem.

Do you have the 2 transducers seperated as much as possible?

You can also angle the fishhawk transducer a bit out to the side and run your probe on the outside rigger closest to the fishhawk transducer. That will help by seperating the underwater signals.

That screw on the back of the fishhawk i was talking about will make it's sending beam wider or narrower. This could help cut down on interferance there.

As far as wiring goes my fishfinder unit and my fishhawk display are 1 inch apart and the power wires go down the same hole. No problem there, maybe i'm just lucky?

does your raymarine and fishhawk read the same speed?

no, not right out of the box.
You have to calibrate them to read the same for a place to start.
get in a calm day in a lake with no currents like winni put on your gps and get the boat set to 2 mph then adjust the down speed screw on the back of the fishawk to read 2 mph and then you will be calibrated to measure for underwater current in places like ontario or whaever.

don't bother with surface speed on the fishawk it is affected by things like waves and moter thrust. paddlewheel surface speed is pretty useless. works ok on some boats.