Al,
Sorry, I didn't mean to suggest you buy a qty of transducers. However,
if you could find a manufacture that was producing some transducer in
quantity for
some other customer, you will pay significantly less than if you say
went to ITC with
a technical specification.
I think you may have trouble beating the pricing for the OTS spares.
You could try going
to one of their distributors or through a scuba shop if they are not
willing to sell them to you directly. I think Amron carries their
gear, so you may be able to get the OTS transducers from them.
http://www.amronintl.com
Potting the transducers is basically just casting them into epoxy or
some similar material.
Two compounds we have used:
Silver Tip Marine Epoxy Series from System Three Resins Inc.
And (epoxy) 828 and (hardener) 1784 from Radarsonics
The main thing to watch out for is that the compounds set fully and you
don't get any air bubbles.
Some companies where we have gotten reasonably cheap ceramics:
SENSOR/B.M. HI-TECH INC.
AIRMAR TECHNOLOGY CO
Also we have in the past gotten 46KHz transducers from Airmar for under
$50 USD in
small qtys, but it was some time ago so I don't know if that pricing is
current.
Of course if you wanted to go whole hog you could buy a furnace and
some pzt powder and make your own transducers.
http://www.amazon.com/Introduction-Theory-Design-Sonar-Transducers/dp/0932146228/ref=sr_1_2?ie=UTF8&s=books&qid=1207923594&sr=8-2
Hope that helps,
-andy
----- Original Message ----- From: "Al Secor" <wreckdiver@frontiernet.net>
To: <personal_submersibles@psubs.org>
Sent: Thursday, April 10, 2008 8:02 PM
Subject: Re: [PSUBS-MAILIST] radio link
Sorry, got two of my links wrong....faulty memory ;-)
www.oceantechnologysystems.com is the correct adr for OTS and
www.divelink.net is correct for the second.
Two additional ones:
www.orcatron.com
http://www.fuji-us.co.jp/e/underwater/
Hope this is helpful to someone.
Andy, I realize that transducers (or anything else for that matter)
is cheaper in quantity but I'm sure as hell aren't going to commit
to any quantity when no one appears interested enough to give me
any input. My reasons for 32 Khz was to be compatible with my OTS
scuba comm which is 32.768 Khz USB but maybe there isn't that much
interest in talking to divers....kind of hard to tell with no
input. I did find some cheap 40 Khz unpotted elements on E-Bay
which are certainly a possibility. Do you have any detailed info
on what's involved to pot them?
Regarding your comment on pingers creating noise...I agree...I was
not intending to run comm and pinger at the same time....Te pinger
function I am going to include in the radio design is more of just
an automated CW (morse code) broadcasted by the radio so it's
signal could be zeroed in on without having someone constantly
talking on the radio.
Al Secor
----- Original Message ----- From: "Al Secor" <wreckdiver@frontiernet.net>
To: <personal_submersibles@psubs.org>; "Rick and Marcia"
<empiricus@telus.net>
Sent: Thursday, April 10, 2008 1:24 PM
Subject: Re: [PSUBS-MAILIST] radio link
If you want something that is tried and true and not half assed then
you need to go ultrasonic as Jay mentioned earlier. The following
companies offer off the shelf solutions for underwater to surface comms:
www.ots.com
www.divelink.com
www.oceanreefgroup.com
There are a few others but these guys are the major players with OTS
probably being the top dog (I speaking strictly non commercial, non
military).
Ir you want reliable (mostly) and non-Mickey-mouse comm, this is the
way to go. It's going to be somewhat pricey but hey, if we can afford
side scan sonar and all other types of expensive "toys" then a
reliable form of surface communication should be affordable.
Now, on a side note, I am working on a cheaper alternative using the
same basic design as the companies listed above. My major stumbling
block is an affordable transducer which I am still looking for and
have not yet found. Most of the ones I've located so far cost as
much, if not more than the costs of the entire units of the above
companies. OTS acts very suspicious when I try to purchase a
"replacement transducer".....
I've mentioned in several previous posts that I am working on this and
pretty much get silence in return so I have to wonder how many people
are actually willing to step up and "pet the pony" and actually
purchase something like this. I couldn't even get a response as to
what people view as an acceptable price to invest in something like
this would be. Right now, my prototype is spoken for and is being
built for Dan H. for use on Persistance. If I don't get any feedback,
this will likely be the only pair of units I will build.
Al Secor - Electrical Engineer for IBM, Ham Radio operator callsign WA3PWX
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