Replacement for LCX-15T sonar

FKPhil · 10 May 2006, 08:32

Any advice on replacing a LCX-15CT sonar ?

I won it in a competition a couple of years ago and it’s always been cr*p (maybe they sent me an ex-demo model or something).

I use it to find wrecks (diving), but even stationary, on a calm sea, with the engine off, it struggles to find a flat seabed if the depth is anything beyond 40m.

After much fiddling about, I found that putting the sensitivity at 100%, Surface clarity and noise reduction at medium it will find the seabed and identify big lumps. But as soon as the engine is on, even just ticking over, interference is so bad, and if combined with a choppy sea it’s more faith than science that the trace you’re looking at actually is the wreck you want.

Transducer is placed at the lowest part of the outside of the transom, well below water, at the same point as the ~ 20 years old Eagle sounder I replaced (which could easily find flattened wrecks well beyond the capabilities of the Lowrance). If I hadn’t given the Eagle away I’d be re-fitting it !

Now that the GPS on the Lowrance has packed in it’s time to cut my losses; I’d prefer separate GPS & sonar but haven’t a clue what sonar is good; basically I want the features of the Lowrance but with the resolution / lack of interference of my old Eagle so I can easily spot small features on a seabed up to 50 metres below.

Sorry for the long winded rant; thanks for listening.

Pete7 · 10 May 2006, 09:22

Whilst your Lowrance seems to have some faults your description points to an engine interference problem too. I suggest this needs fixing first. In addition to the engine check the wiring to the battery is okay and the sounder hasn't been wired directly to the engine aux circuit.

I really do like the Lowrance / Eagle kit for sounders and you soon get used to the quirky menus but my Garmin GPS is also very simple just not sure about the power of there sounders. I have always tried to use the higher power Lowrance / Eagle sounders like you and found the picture quality and ability to find flat wrecks excellent, supprised the 15 doesn't work well then. Perhaps you should choose a stand alone Eagle sounder and Garmin GPS.

Fancy selling your LCX 15 ?

Pete

Simon B · 10 May 2006, 12:55

Does sound like interference that can be got rid of, our new 107Cdf finder is excellent it will wee a rope down to a wreck, BUT, this was after some time finding then fiddling with the optimum settings.

From Manual;

"If noise appears on the display, the problem could be one of three things; spark plugs, alternator, or tachometer wiring. Try using resistor spark plugs, alternator filters, or routing the sonar unit's power cable away from engine wiring. Again, routing the power cable directly to the battery helps eliminate noise problems. Make sure to use the in-line fuse supplied with the unit when wiring the power cable to the battery. When no noise appears on the sonar unit after all of the above tests, then the noise source is probably cavitation. Many novices or persons with limited experience make hasty sonar installations which function perfectly in shallow water, or when the boat is at rest. In nearly all cases, the cause of the malfunction will be the location and/or angle of the transducer. The face of the transducer must be placed in a location that has a smooth flow of water at all boat speeds. Read your transducerowner's manual or the Installation instructions (Sec. 2) in this manual for the best mounting position."