NASA Log

[whiteoaks7]

My Target log is susceptible to electrical noise to an extent where it is unusable when motoring. I have tried all manner of filters (capacitors, varistors at the alternator; a pi filter at the power feed to the log) to no avail. The thing is clearly not tolerant of anything that makes sparks - I ran a small pump on board last week and the readout changed from 2 knots (sailing) to 10 knots. Does anyone have any ideas - if this is cable bourne noise I may have a chance; if it's radiated then I probably don't, but how could NASA sell something so susceptible?

All help gratefully appreciated.

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[chriscallender]

I wonder if there is something wrong with your target, because I have fitted them to both my old and new boat and never had any of this kind of trouble. Old boat was petrol 2 stroke outboard, so plenty of sparks. New boat has a Bukh 20 diesel so maybe less of an issue with ignition noise but I have never noticed a problem eg when switching on the bilge pump.

Perhaps the grounding of the cable that goes to the transducer from the log is broken, in that case it might still work but be susceptible to picking up noise.

Anyway I don't think that the NASA gear is too bad in general, my experience has been that they are budget instruments, functional but lacking the bells & whistles of more expensive instruments.

If the log is still in warrenty, your best bet would be to return it saying you've installed according to instructions and it don't work. Then try a replacement to see if its any better. If out of warrenty ideally you could try to borrow a transducer from somewhere, connect it to your log and see if it works any better. The transducers are available seperately if thats where the problem lies.

Chris

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[Paul_H]

Theres a whole heap of things that could be causing your problem incl. a faulty log or transducer. Here's a few to think about:
Have you got paired power cable (fig8 or twisted) of suitable current capability running as far back to the battery as possible? Use a separate wire run, dont tap it part way into other circuits where it can pick up noise from those circuits.
Is the transducer connected correctly especially the screen?
Was your PI filter up to the job? Filtering needs to go across the supply wires as close to the instrument as poss. and needs to be appropriate for the interfering frequencies. High frequencies are easy to filter but low frequencies such as that from dc motors needs big chokes and capacitors.

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[vyv_cox]

B&G Depth

My B&G H1000 depth has given considerable problems since new, reading 120 metres in 25 and zero whenever the water was turbulent. Since the transducer was replaced - no further problems (yet).

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[milltech]

Always happy to sell a transducer and take it back again, you lose £2.95 on the postage. The return must be pristine and resaleable so test over the side not in the bilge please!!


<hr width=100% size=1>John
<A target="_blank" HREF=http://www.allgadgets.co.uk>http://www.allgadgets.co.uk</A>

 

[Strathglass]

Thanks for the quick delivery John.(NASA wind cups/extention cable and watches, including the free one) However we have come to expect this and if the items are not in our hands within a couple of days we will start to say that your standards are slipping.
Keep it up John, it gives us a good standard to judge others againsy

Iain

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