Sounder interference?

[FishFinger1977]

Hi all,
Both sounders at speed in shallow water up to 10m or so they both read fine however when in deeper water they get interference so much so that you can't read them at all, they are ok to read at idle in gear but any rev over 1000rpm and it is crap. Would it be the two sounders interferring with each other as the cables run along side each other and for that matter along all the other wires. I originally thought it was interferrence from the other wires because it happens at 1000rpm or more in deep water but this may not be correct as they are both fine at speed in shallow water.

The colour sounder was mounted in a rather silly way and it has since been moved and the guy said it would fix the problem but the other thru hull transducer still had the same problem as well so maybe it is more than a movement of one transducer hence I thought it was interferrence. Any ideas? I will try to turn on off next time incase the khz is the same frequency and this will cause the above but would it not do it at slow idle as well? Any ideas are much appreciated. Regards Scott

[banshee]

If they are both opperating on the same frequency then I don't you will stop the interferance successfuly,you may be able to screw up the filters etc but this could detract from what you were hoping to find in the first place,I know if anyone comes within 30 yards of me with 200khz on, my sounder plays up badly with 45 degree blue lines all over the screen.

[dfox]

The sounders being so close together and using the same frequency have to interfere with one another,its impossiable for each unit to distingish its signal. Maybe and im guessing ,but at shallower depths and less gain the problem isnt as bad. But at greater depths and more gain the effects of having two units on have to effect the signals.
The question has to be asked why you,d use two sounders on the same frequency anyway?
When two boats pass close to one another both with sounders on you normally pic up verticle interference lines on the sounder is this what your receiving?...foxy

[FishFinger1977]

Thanks guys for the replies, Banshee and foxy I do not actually know if the sounders operate on the same frequencies, one is a lowrance x45 and the other is a koden cvs 106 colour sounder, even if one is turned off it still has the problem in deep water over 1000rpm, tomorrow i'll separate the transducer cables from the other electronics and see if that makes a difference when I go out again. I only had the lowrance on as it gives a good depth indication when all the crap appears on the screens. Thanks anyway guys but with the transducers new location and the wires separated from all the others hopefully this will fix the prob. Also I set the gain on the koden to 10% of the depth as instructed by a mate this did help no end but still did not stop the interference. Regards Scott