RE: [PSUBS-MAILIST] Hydrophone test

["Jens Laland" <laland@artematrix.org>]

Guys

I'm flattered, but I have no real experience on any of these matters,
although I did run a simple bench test on David's HBH-2 hydrophone to
determine the resonance frequency of it's piezoelectric element, ref

http://www.psubs.org/projects/common/scripts/display/bigpic.cgi/projects/1234567815/passivesonar/1265151470.jpg

But such an undertaking as the one indicated above does not make me any
more qualified to advice somebody on how they should go about testing
their own sonar hydrophones (especially not calibration tests).

Having said that, I am more than willing to participate in any discussion
that would educate and assist us to establish proper testing procedures,
and eventually, to conduct reliable calibration tests on any type of
homemade (or commercial, for that matter) sonar transducers.

For those interested, I will (again) recommend that you study my
transcription from the book "UNDERWATER ELECTROACOUSTIC
MEASUREMENTS",(Chapter II : Methods and Theory) by Robert J. Bobber, Naval
Research Laboratory, Underwater Sound Reference Division, Orlando, FL
(1970). This text can be found at this link, ref

http://traktoria.org/SONAR/transducer-calibration/transducer-calibration.htm

Should anyone remonstrate against having detailed discussions pertaining
to sonar technology in this forum, then maybe those ought to be held
off-list.

Best regards,
Jens Laland

**
**      Jens would be the person to ask just how to test these and other
** hydrophones. My method is really a go no go thing and this works
** better than that.
**
**> David,
**> I compared the units just by ear, they responded equally. Do you have
**> a suggestion for test measurements? My "test tank" is a steel box 38"
**> x38"x 30" deep.
**> Jim R.
**>
**> > Great work! How well did it pick up?
**> > David Bartsch
**> >
**> >> I have tested all the BQR-2a hydrophones in water. They were
**> connected
**> >> to a Radio Shack 1 watt PA amp using the mic input. Its a Realistic 1
**> >> watt speaker/amp, model 32-2040. All have the same output (by ear)
**> >> when thumping the steel reservoir side.
**> >> One hydrophone was cut removing a short strip of the rubber covering.
**> >> There is a potting compound which could be a silicone sealant.
**> >> Photo attached.
**> >> Jim R.





************************************************************************
************************************************************************
************************************************************************
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
************************************************************************
************************************************************************
************************************************************************