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Jens, One of the primary reasons for having researched this hydrophone and developing our ability to listen to underwater sound is so that once our dives are coming to an end, we can surface with less fear of hitting surface traffic. In this way, we are self regulating and ensuring the safety as best we can of this ever popular sport. The other result was that we discovered that not only could we hear ambient noise and boat traffic, but we could also communicate from sub to sub while still submerged. Although this system is relatively inexpensive to build, the results we are seeing rival many systems far more complex and also offers those with smaller budgets the ability to build these themselves. I do not have 27k to throw at a submarine construction project much less only the communications system on one. With the range goal of 500' apart having been met, we only need to ensure that the 500' feet deep portion is satisfied also. Testing in salt water for those who venture into the big blue would be nice also. Many people have worked hard as a team to get where we are now and continue to make strides I never thought we could have. We truely have come a long way already. David Bartsch > Date: Tue, 27 Oct 2009 02:32:13 +0100 > Subject: Re: [PSUBS-MAILIST] sonar research progress report. > From: laland@artematrix.org > To: personal_submersibles@psubs.org > > David > > It is always of great interest to me whenever you have news about your > various projects. This has been, and still is an inspiration for me in my > own attempt to learn more about the fascinating sonar technology. > > In connection with your test, you stated: > > ** Both transmitter and hydrophone were at three feet depth. > > My feeling is that you should have gone a bit deeper. Allow myself to > quote from J.W. Horton's book 'Fundamentals of Sonar' when he speaks about > direct listening: > > "One requirement which must be met if the interference, as it exists in > the water, is not to exceed the the minimum water noise level is that the > listening operation shall be carried out in deep water far from shore. It > is further necessary that the hydrophone be submerged to at least 20 ft. > below the surface, > > [... that it be motionless in the water, and that there shall be, in its > immediate vicinity, no ships or other bodies floating on the surface and > no submerged machinery or other primary sources of sound.]" > > I wish you good luck with your ongoing projects. > > Best regards, > Jens Laland > > > > > > ************************************************************************ > ************************************************************************ > ************************************************************************ > The personal submersibles mailing list complies with the US Federal > CAN-SPAM Act of 2003. Your email address appears in our database > because either you, or someone you know, requested you receive messages > from our organization. > > If you want to be removed from this mailing list simply click on the > link below or send a blank email message to: > removeme-personal_submersibles@psubs.org > > Removal of your email address from this mailing list occurs by an > automated process and should be complete within five minutes of > our server receiving your request. > > PSUBS.ORG > PO Box 53 > Weare, NH 03281 > 603-529-1100 > ************************************************************************ > ************************************************************************ > ************************************************************************ > Windows 7: I wanted more reliable, now it's more reliable. Wow! |