NASA DEPTH INTERFERENCE

[CORBIEREV]

I HAVE FLUCTUATING READINGS WITH THE ENGINE ON (JOHNSON 9.9 SAILMASTER). I'VE TRIED RUNNING IT FROM A SEPERATE BATTERY; WRAPPED THE OUTBOARD & WIRING IN COOKING FOIL LEAD TO EARTH; HUNG A DIFFERENT TRANSDUCER OVER THE SIDE; ASKED NASA WHO SAID SUPPRESSOR ON ALTENATOR (BUT IF ISOLATED BATTERY DOSEN'T WORK?); SPOKE TO IT NICELY, SHOUTED AT IT......... SOMEONE SAID SUPPRESSED PLUGS? DO THEY DO 'EM FOR OUTBOARDS? WILL THEY WORK(WILL ANYHTING?)

 

[oldharry]

Obviously the engine is causing the intereference - so as NASA suggested, you should work to reduce said interference. Even if its on a seperate circuit, radiated interference can be causing a problem. Try suppressing the alternator as NASA suggested. Use resistor type plug caps on the HT leads (try your local Mcycle shop), and suppressed plugs - in the NGK range they have the same Code, but include an R in the plug code, so that a B7HS becomes a BR7HS.
Is your tranducer cable near the engine or charger wiring? If so move it at least a Metre away from anything connected to the engine.

Shouting relieves the feelings, but doesnt work.... and might frighten the poor little thing into giving up altogether. Not to mention your crew....

 

[CORBIEREV]

OldHarry, thanks for the suppressed plug/cap advice, I will give it a try.
P.S. I've stopped shouting at it and started drinking beer instead. Can I get a NMEA 0183 interface for my liver?

 

[oldharry]

Re: NMEA 0183 interface

Try Johnnie Walkers, Scotland....

 

[roger]

My NASA is subject to electronic interference from passing warships!. My transducer is in an oil tube inside the hull. I've assumed that the very thick hull means I get very little signal back. Could this be your problem?

 

[oldharry]

Warships can do some very strange things to electronics - try using a GPS anywhere near one. Probably something to do with the powerful radar and guidance systems they use.