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Frank, As Jon was able to determine by his kayak delving, the HBH hydrophone at the present time is only good for grid type searches. This is to say a search pattern of back and forth and listening for the level of sound detected is about as good as it gets with this device...for now... A hydrophone is under investigation that may provide a search capability in the near future but as I said, this is still under development. The results on this unit should be comming this Summer. David Bartsch From: ShellyDalg@aol.com Date: Sun, 14 Mar 2010 23:58:35 -0400 Subject: Re: [PSUBS-MAILIST] Desert Star Sport To: personal_submersibles@psubs.org In a message dated 3/14/2010 8:06:39 P.M. Pacific Daylight Time, alanjames@xtra.co.nz writes:
I have only had experience with cheap fish finders & have questions about their reliability, Hi David and Alan. Gulping air......well, OK.
Now back to the question of finding a sub......
If a sub has a pinger attached, could a surface boat find it with the hydrophone you ( David ) made ?
Depending on directionality of the array, a direction for the sub's location should be possible. Maybe then the pilot could motor over in that direction and as the pinger got louder you may be able to tell how close you're getting. At least staying within a pre-set minimum distance. By rotating the pick-up you would know if the surface boat needs to go left or right. Now, if you passed OVER the sub and the pinger signal was now coming from behind the pick-up the pilot would then stop or get out of the way in case the sub was ascending to the surface. Be a bummer to ram your own surface crew.
Maybe you could have two pingers with one stronger ( louder ) or more frequent so by listening you'd be able to tell how close you were. What makes a pinger anyway ? Is it just a thing that sends out a sound wave at a set interval ? It seems the pick-up part is the hard piece to make. So the returning signal can be figured how far away it is ( function of time ? ) and what direction it's coming from ( array set-up in degrees ?)
Frank D.
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