RE: [PSUBS-MAILIST] Suggestion for UW comms

["Al Secor" <wreckdiver@frontiernet.net>]

Interesting to see this subject cycle around every now and again.  A year or
so ago I mentioned I have a design and circuit boards for an SSB UQC based
on a cave radio that I was going to modify to drive an ultrasonic
transducer.  Nobody seemed interested at the time so I dropped development
of it at the time.  The design was for 32.750 khz so it would be compatible
with most scuba based comms like OTS, Divelink, and Orcatron.  The problem
was (and still is) finding an affordable transducer designed for that
frequency.  I contacted most of the major transducer mfgs and they all
wanted BIG BUCKS (read $$$$) for their off the shelf transducers.

I have enough transducers of my own to build 1 radio pair but to build
additional ones, I would need a source for additional transducers.  Even if
I can obtain transducers from one of the comm. Companies such as OTS, they
won't be "CHEAP"...we're probably talking $200+ for EACH transducer and you
would need 2, 1 for the sub and one for the surface radio.  That means you
have $400 - $500 invested before you even begin the electronics.
Again...NOT CHEAP!!!  I personally don't think there is such a thing as a
cheap, reliable, underwater communications solution except maybe for Jens'
suggestion of a 2-wire telephone link to the surface but then again, like
Jay mentioned...that would not necessarily be reliable due to problems with
wire breakage / maintenance.  

Again, at the time I advertised my radio solution, no one seemed interested
so I stopped development on it.  (I also had other commitments and problems
that prevented me from continuing work on it at the time).  If PSUBS would
like me to continue development on it, I can start the project back up this
winter.

I also have bought several of those pingers off of Ebay.  I actually
contacted the seller and he was willing to sell be all I wanted at $10 a
piece.  At the time, I was hoping to be able to scavenge the transducer from
them but the electronics and transducer are totally potted in epoxy and no
matter how carefully I tried to dissect it, I didn't have any luck.  BTW,
these are designed to be run off a 9v battery and are activated when it
comes in contact with water across 2 exposed screws.

With regards to a standardized connector...the OTS transducer uses a 2 pin
AMP modular waterproof connector.  I can get the part number later.  The
only problem is it is plastic instead of metal.  I believe there's a 4 pin
version of this also but I suspect David's hydrophone could be modified to
work with a single transducer for both transmit and receive.

Al - WA3PWX

 




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