Subject: Any info about depth sounders?
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Date: Sat, 7 Dec 2002 14:06:14 -0000
NNTP-Posting-Date: Sat, 07 Dec 2002 14:05:46 GMT
Organization: ntl Cablemodem News Service
Sorry if this appears twice - my server just told me it didn't send the
Can anybody give any advice, or preferably a schematic for a depth sounder
for a boat?
I want to design a combined speed/distance log and depth sounder using sound
waves through the water, but this is an area that I haven't been into
before. I can get ultrasonic transducers from Maplin, but I don't even know
if ultrasonic is the best frequency to use. All those old films of people
sweating in submarines while the destroyer above tries to sound them out,
used an audible 'ping'. Is that a more trasmissive frequency to use in sea
water, or was it just that ultrasonics wasn't really available during the
last world war? When I find the best frequency to use, how many cycles
should in build into the ping? An echo from a hard bottom probably isn't too
difficult, but if the botton is soft mud?
The other thing is - the ultrasonic transducers from Maplin normally work in
air. What is the best way to couple the sound to the water - by having an
air gap in front of the transducer, or by potting the transducer in a tube
full of waterproof potting compound which dips into the water?
I'm really on the footslopes of the learning curve on this one, so any
guidance would be appreciated.
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