Amp Inc in Gettysburg PA has some extruded Kynar cylinders
about .5" diam, and 1" long that makes a great receiver.  That
is what they are made for, specifically.  They don't make very
good transmitters, though.  You do better with ceramic.

I made a little PC that fits inside of the Kynar cylinder, and
provides two stages of amplification, and bandwidth trim.  Once
it is in place, I mold it into a urethane shape that fills all voids.
The urethane is waterproof and is transparent to sound.
Great hydrophone.  I have dozens of the boards, if anyone is
interested.

BTW, I am wondering if there is any garbage attached.  I called
Microsoft, and they gave me their version of how to suppress it
in Outlook 97.  If they are right, email private, and I will reveal
all.

-----Original Message-----
From:   Alessandro Zummo [SMTP:azummo@ITA.FLASHNET.IT]
Sent:   Tuesday, March 10, 1998 12:40 PM
To:     PICLIST@MITVMA.MIT.EDU
Subject:        Re: OT: Radio Transmission in Water

Il 10-Mar-98, The Jacky's scrisse:

> Water conducts sound extremely well , better (and faster) than air.
> I thinking in a very free form mode here but you could rip the
> transducers off a couple of old fish finders and use em for tx and rcv.
> units.
> I think these guys operate above 30 KHz.  You may be able to modulate
> enough info on to the carrier to do slow frame video.

The question is: where can i get them and how can i protect
any other emitter from water without loosing it's capabilities...

--

   - *Alex* -

  http://freepage.logicom.it/azummo/