David,
In open water (salt) you are going to have varying irreproducible
results due to background noise (biologics + man-made), back scatter,
reverberation, temperature, and salinity issues. Most of these will
degrade a given signal and reduce dependability. Some days it might work
and others it might not. Freshwater is a more reasonable environment for
your endeavor. It is a complicated process to determine the maximum range
which will vary from place to place.
You need to be careful with casual underwater comms as you may be
happy with relatively poor capability while chit-chatting but in an emergency,
clear dependable communications is mandatory to increase the probability of a
successful emergency resolution.
R/Jay
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 David
Bartsch
Sent: Saturday, November 15, 2008 12:44 AM
To: personal_submersibles@psubs.org
Subject: RE: [PSUBS-MAILIST] sound transducers
Jay,
What then would you think would be the maximum range of a broadband
voice system? Do you feel that 150' apart and both systems 150' deep is achievable?
Is fresh water the best medium for this system?
This was an attempt to aid two submarines working together or perhaps
talking to its support boat. Do you think this goal is beyond reach with this
set up? It was designed to be as simple as possible to aid persons not rehersed
in electronics to be able to put these together with minimal assistance.
You stated that salt water had odd effects on sonar reception as
compared to fresh water...this was shown at the convention with boats picked up
much better in salt water than in fresh. The acoustical pinger was masked by
passing boat traffic.
Please share what you know...
David Bartsch
From: bottomgun@mindspring.com
To: personal_submersibles@psubs.org
Subject: RE: [PSUBS-MAILIST] sound transducers
Date: Fri, 14 Nov 2008 21:57:58 -0500
Joe,
For efficient transmission, the signal
is translated in frequency (still audible but unintelligible) to maximize range
and single side-band is used to conserve energy. Anything else will have
difficulties of one form or another. Opening a basic sonar acoustic text
will document this, you can’t get around basic physics.
R/Jay
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, November 14, 2008 4:55 PM
To: personal_submersibles@psubs.org
Subject: RE: [PSUBS-MAILIST] sound transducers
David,
Not having any field experiences and out of curiosity, this brings to mind a
question regarding underwater voice transmission in general.
I've seen voice comm between Alvin and Atlantis, Calypso and the saucers,
habitats,...etc.
Is this voice comm severely scrambled (distorted by the seawater), and then
reprocessed by the receiving equipment?
Or, put another way, if I swim between divers with voice comm equipment,
could I hear the conversation like I do prop noises?
Joe
From: dbartsch2236@hotmail.com
To: personal_submersibles@psubs.org
Subject: [PSUBS-MAILIST] sound transducers
Date: Fri, 14 Nov 2008 15:36:04 -0500
To all:
The transducer for solids from which can be made the broadband
voice transmitters are available on e-bay under "underwater speaker"
at this time. These are selling for $26.95 but shipping is being provided. This
is not a bad price if you were concidering delving into this area of study.
With a singing machine that is battery operated, a voice
transmitter can be made from the use of this. (It still needs to be imbedded in
molding plastic to survive deep depths.) And you will still need a means of
hearing the return responce.
It sure would be great to talk back and forth between two
submerged submarines or to your support boat without having to surface first.
David Bartsch
Windows Live Hotmail now works up to 70% faster. Sign
up today.
See how Windows® connects the people,
information, and fun that are part of your life Click
here