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Re: [PSUBS-MAILIST] Hydrophones



Jon

I look forward to seeing the documentation.  What was the range capability to the pinger in sea water? 

Have A Nice Day.
Doug


-----Original Message-----
From: jonw@psubs.org
To: personal_submersibles@psubs.org
Sent: Sat, 30 Aug 2008 1:32 am
Subject: RE: [PSUBS-MAILIST] Hydrophones

I forgot to include something here.
 
>The attractiveness of the home-built models is their very inexpensive
>fabrication costs, about $10 for a hydrophone depending upon how
>much the wiring costs you, and $20 for the pinger (only because we
>used a $12 Radio Shack buzzer as the acoustic transmitter).
 
We determined that the Desert Star Scout and Sport models are a much better solution due to their ultrasonic frequency.  And PSUBS can get you a discount on it as well.  I don't believe the frequency they use meets ABS specs either, but Andy can comment on that.  I think ABS requires 37.5khz?  Or was it 36.5?
 
Andy, by the way, whatever the ABS frequency is, any chance of Desert Star changing to that frequency?
 
Jon
 
-----Original Message-----
From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org]On Behalf Of jonw@psubs.org
Sent: Saturday, August 30, 2008 2:26 AM
To: personal_submersibles@psubs.org
Subject: RE: [PSUBS-MAILIST] Hydrophones

Doug,
 
The pinger is included in the slides and is easy to construct.  Be advised it is a 3.2Khz audio pinger and does not conform to ABS standards.  We also had no luck with directionality using the hydrophones as currently designed, however Lynn Darnell is looking at this issue.  From the surface, it was fairly easy to home-in on it using a grid type search pattern since it's easy to hear when you are getting closer to it.  In fresh water, the pinger and hydrophone combination worked very well.  In salt-water it was quite a bit less effective, just as Jay Jeffries had suspected it would be.  In the testing we did in salt-water at the convention, the hydrophones were much more sensitive to passing motor boat traffic than they were in fresh water.  At one point, the noise from a motor boat was so loud that it was difficult to hear the pinger.
 
The attractiveness of the home-built models is their very inexpensive fabrication costs, about $10 for a hydrophone depending upon how much the wiring costs you, and $20 for the pinger (only because we used a $12 Radio Shack buzzer as the acoustic transmitter).
 
I'm going to have to split up the slide show into multiple files because it is HUGE as is.  If that's not feasible, I'll just create CD's and ship them out to people.
 
I'm glad to see interest in this.  As I've said from the beginning, these units should be considered prototypes that can stand LOTS of improvements from smarter people out there, than me.  Have fun with the existing models and feel free to make them better.
 
Jon
-----Original Message-----
From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org]On Behalf Of djackson99@aol.com
Sent: Saturday, August 30, 2008 1:54 AM
To: personal_submersibles@psubs.org
Subject: Re: [PSUBS-MAILIST] Hydrophones

Good, I look forward to the plans.  Do you guys have a pinger too?  --Doug