Sent: Sunday, May 13, 2007 4:02 AM
Subject: [PSUBS-MAILIST] Dolphinear
hydrophone...we are NOT impressed...
Hi psubbers,
Today I got my hydrophone ! - so my first action
was to rush to the harbor, get into the submarine and sail her surfaced out
into the main basin of Copenhagen harbor. I plugged in my new Dolphinear
Hydrophone System together and lowered it down from the deck of the
submarine.
In the earphones I hear noise - loud noise. Its
sounds mostly like static on a radio with no antennae - I try to adjust
gain assuming that the amplifier is just very good and that its
amplifying the background noise of the sea...hmm...then a big motorship
comes nearer - and passes me at distance of about 20 meters. Regardless of
orientation, depth and gain - there is no way that I can detect a big motor at
20 meters range. Just the same static noise. I disconnect the hydrophone to
clear is this is an amplifier problem - and the noise almost
disappears - I reconnect NOISE- and pull the hydrophone back up - and above
water the noise is a little different.
Hm...conclusion...the device can possible detect
if its submerged or not - the noise origins from the sensor - but is not
correlated to anything outside the sensor - tapping on it will be heard
as a change in the noise pattern...so something does work.
My example has no use in detecting anything like
a ship - it could not detect my own boats propeller or engine.
If this is the last word in
hydrophones...then I prefer to be deaf.
Best regards,
Peter
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