RE: [PSUBS-MAILIST] Hydrophones/Pingers

["Andrew Goldstein" <ag@desertstar.com>]

All,

Jon is correct in that the sport and scout are at around 70 kHz,
and ABS specs out relocation pingers at 37.5 kHz.  I think ABS specs out 
other parameters (bat life, source level, depth rating, etc.) that the sport/scout may not meet.
If anyone has the abs spec in front of them please correct me or clarify.

A proper redesign to 37.5 kHz at the sport/scout price range probably will not be done.
This would require new transducers, housings, and some software and electronics mods.  Not
hard, but unlikely we could make any money on it.  One of the major factors in setting the
price of the sport/scout is the fact that we can get the 70 kHz xducers at low cost.

We do have other hardware that can currently meet the ABS spec (at least in terms of freq. and maybe in the
other parameters) but the cost is significantly more than the cost of the scout transmitter.

There are other manufactures (Benthos, RJE, Dukane) who make pingers that conform to abs specs. 

When I get the time I can look into instructions for modifying the sport (easier than the scout) to operate at
37.5 and post them for anyone interested.

-a

-----Original message-----
From: jonw@psubs.org
Date: Sat, 30 Aug 2008 06:34:29 -0700
To: personal_submersibles@psubs.org
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
> 
> 
> 
> 
> 



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