Jay,
Interesting,...explains what I see mounted on the old fleet boats with that funny shaped array.
In that scenario regarding the lobes, if I understand you correctly, the problematic determination of direction is for a sound source that is maintaining a fixed bearing, is this correct??...which would be bad news if it's getting louder!
So if you have a prop sound that is in fact changing bearings, could you reasonably determine if it were P or S, converging or not?
Joe
From: "Jay K. Jeffries" <bottomgun@mindspring.com>
Reply-To: personal_submersibles@psubs.org
To: <personal_submersibles@psubs.org>
Subject: RE: [PSUBS-MAILIST] Hydrophone systems
Date: Fri, 11 May 2007 11:45:09 -0400
Joe,
An array is needed, for my home-built side-scan sonar, 4 transducers in a series-parallel combination formed a sufficiently narrow beam for scanning. Would guess a similar hydrophone array would produce satisfactory results. One thing to keep in mind depending on what type of hydrophone is employed; there will be 2 opposing lobes off of the phone?determining which lobe is hearing the noise source can be an issue. If the hydrophone is pointed forward and the strongest signal is received in this position, the source could be dead ahead or dead astern.
R/Jay
Respectfully,
Jay K. Jeffries
Andros Is., Bahamas
A skimmer afloat is but a submarine, so poorly built it will not plunge.
From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] On Behalf Of Joseph Perkel
Sent: Friday, May 11, 2007 7:58 AM
To: personal_submersibles@psubs.org
Subject: RE: [PSUBS-MAILIST] Hydrophone systems
David,
Free is always the "right price"! I cannot be there but, look forward to seeing the results.
Let me ask you this,... what can a homebuilder expect in terms of narrowing the bearings to prop sounds to say... within 5 deg? Is that a reasonable expectation?
Joe
From: "David Bartsch" <dbartsch2236@hotmail.com>
Reply-To: personal_submersibles@psubs.org
To: personal_submersibles@psubs.org
Subject: RE: [PSUBS-MAILIST] Hydrophone systems
Date: Thu, 10 May 2007 23:32:25 -0400
>Joseph Perkel,
> Nice hydrophones...my plans are free and will be available at the
>upcomming convention!
>
>
>>From: "Joseph Perkel" <joeperkel@hotmail.com>
>>Reply-To: personal_submersibles@psubs.org
>>To: personal_submersibles@psubs.org
>>Subject: [PSUBS-MAILIST] Hydrophone systems
>>Date: Thu, 10 May 2007 18:44:20 +0000
>>
>>
>>Peter and others,
>>
>>When I was considering a war-boat replica, I had gone as far a
>>acquiring plans for a homemade directional hydrophone.
>>http://www.digitalmarketingusa.com/hydrophone.html
>>
>>There are a number of commercial, albeit expensive units that are
>>off the shelf such as
>>http://www.sonotronics.com/html/products/receivers/mantrak.html
>>
>>The idea being that one could mount such a device atop a short
>>shaft through a simple rotating thru hull. One could have a fixed
>>compass rose on the inside with the bow of course aligned
>>@ 360 deg, in order for the operator to determine and call out
>>bearings.
>>
>>When I was diving, I was fairly certain within.... I would guess a
>>90 deg swath of the direction of props to try to keep myself from
>>being blended. This is with human ears so I am quite sure these
>>units will get that down to the degree.
>>
>>If you really want to get fancy, there are software programs
>>available that will determine range based upon density and sound
>>wave propagation. This could be run on a Panasonic "Toughbook".
>>
>>Joe
>>
>>
>>
>>
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>
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