sonar "noise"

[captn-tin]

have lowrance 332c on 18' lund. have rerun all wires to get them away from engine wires, etc. this has cleared up the screen a little. i'm now looking at replacing the reg plugs(ngk lfr6a-11) with resistor plugs.does anyone have a plug # for replacement of the original plugs? these will be for a 2001 yamaha f115 4-stroke. do you think this will help much? thanx in advance.

 

[Boatin Bob]

Re: sonar

Re: sonar

Looks like you are already using resistor type plugs, that's what the R is in the LFR6A-11.

 

[Texasmark]

Re: sonar

Re: sonar

You might try a "snubber capacitor" where your power enters your sonar cable. Real short leads, 0.1 microfarad, 50dcwv or more, ceramic material, capacitor (condenser) at Radio Shack.

Place it right across the + and - terminals. Shield and dc return both should be on the - terminal.

You have conducted emissions and radiated emissions. Conducted are the worst usually, but the easiest to control. This attacks conducted. Cost, 50 cents.

The only radiated emissions you have (to speak of) are from firing your plugs and they only affect wires in the vicinity of the plug and the hv lead of the pulse module.

If they get on the power supply to the pulse module (from inside the pulse module) they cease to be radiated emissions, they are now conducted emissions and your little snubber will snub them out. 8)

Mark

 

[captn-tin]

Re: sonar

Re: sonar

Texasmark....Thanx for the info on the snubber capacitor.I finally got to Radio Shack and purchased one. Question.... since I am a butcher, not an electrician, would you please explain exactly where and how to connect this piece to the unit.You probably explained it in your first response and I did not absorb it. Thanks.....Captn-tin

 

[bruceb58]

Re: sonar

Re: sonar

capt-tin,

That capacitor is probably not going to do anything to help you. You would be way better off putting a choke in-line. You can make a pi filter that would do a much better job. Do a search online to see what I am talking about. Most aftermarket filters for this type of problem are most likely a pi filter structure.

Another thing I would suggest is to twist your power and ground lines and run them by themselves directly to the battery. They are easy to make, Chuck your two wires in an electric drill, have a helper hold them on the other end and operate your drill until the wires are twisted together.

I would also give Lowarance a call. They probably have seen this problem and can suggest in-line noise filters that you can mount up near the unit to suppress most of your noise.

I am actually surprised you are getting that much noise. Lowrance more than likely does some filtering of the incoming power. You may have something wrong with your unit.

bruce