Underwater communication
Archiver
Posts: 46,084
Anyone have an idea on how to send a wireless signal a distance of about 100
feet underwater. Does RF work under water? I just want to use a stamp and
send a signal to another stamp to turn on a light. Any ideas would be great.
Thanks in advance,
Jason
feet underwater. Does RF work under water? I just want to use a stamp and
send a signal to another stamp to turn on a light. Any ideas would be great.
Thanks in advance,
Jason
Comments
At 09:11 PM 5/22/02 -0400, you wrote:
>Anyone have an idea on how to send a wireless signal a distance of about 100
>feet underwater. Does RF work under water? I just want to use a stamp and
>send a signal to another stamp to turn on a light. Any ideas would be great.
>
>Thanks in advance,
>
>Jason
>
>
>
>To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
>from the same email address that you subscribed. Text in the Subject and
>Body of the message will be ignored.
>
>
>Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
Larry G. Nelson Sr.
mailto:L.Nelson@i...
http://www.ultranet.com/~nr
jack up the signal strength of which I dont think you can do. That is why
the Navy uses Very Low Frequency signals to communicate to subs under water.
VLF is in the 10s of hertz.
Original Message
From: "Jason W. Day" <j_w_day@y...>
To: <basicstamps@yahoogroups.com>
Sent: Wednesday, May 22, 2002 8:11 PM
Subject: RE: [noparse][[/noparse]basicstamps] Underwater communication
> Anyone have an idea on how to send a wireless signal a distance of about
100
> feet underwater. Does RF work under water? I just want to use a stamp and
> send a signal to another stamp to turn on a light. Any ideas would be
great.
>
> Thanks in advance,
>
> Jason
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
my pool here in Pasadena CA.
Dennis
Original Message
From: David Wright [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=GMNufC9Z7LKPygOhaDh02VTOwVkTWtB6sQKoDjxnnoJ8axjGbDhU0TLawUIKuRbYyd1JbKLZ1-8pgPpWwXHN0g]dwright3@a...[/url
Sent: Wednesday, May 22, 2002 8:04 PM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] Underwater communication
Niches Werste buddy, RF underwater aint going to go far unless you
really jack up the signal strength of which I dont think you can do.
That is why the Navy uses Very Low Frequency signals to communicate to
subs under water. VLF is in the 10s of hertz.
Original Message
From: "Jason W. Day" <j_w_day@y...>
To: <basicstamps@yahoogroups.com>
Sent: Wednesday, May 22, 2002 8:11 PM
Subject: RE: [noparse][[/noparse]basicstamps] Underwater communication
> Anyone have an idea on how to send a wireless signal a distance of
> about
100
> feet underwater. Does RF work under water? I just want to use a stamp
> and send a signal to another stamp to turn on a light. Any ideas would
> be
great.
>
> Thanks in advance,
>
> Jason
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject
> and
Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
>
>
To UNSUBSCRIBE, just send mail to:
basicstamps-unsubscribe@yahoogroups.com
from the same email address that you subscribed. Text in the Subject
and Body of the message will be ignored.
Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
Depending of your application you may
need an expensive accoustic modem (for noisy environments like seashore or
shallow waters and omnidirectional
ranging) or a simple circuit with 2 piezo transducers one to send and one to
receive with an amplifier. Some
considerations regarding with transducers will be water coupling and
encapsulation method , attenuation,
directivity, power, ressonant frequency, modulation etc.
ACJacques
"Jason W. Day" gravada:
> Anyone have an idea on how to send a wireless signal a distance of about 100
> feet underwater. Does RF work under water? I just want to use a stamp and
> send a signal to another stamp to turn on a light. Any ideas would be great.
>
> Thanks in advance,
>
> Jason
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and Body
of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
(sonar)
On Wed, 22 May 2002, Jason W. Day wrote:
> Anyone have an idea on how to send a wireless signal a distance of about 100
> feet underwater. Does RF work under water? I just want to use a stamp and
> send a signal to another stamp to turn on a light. Any ideas would be great.
>
> Thanks in advance,
>
> Jason
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and Body
of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
Sean T. Lamont, CTO / Chief NetNerd, Abstract Software, Inc. (ServNet)
Seattle - Bellingham - Vancouver - Portland - Everett - Tacoma - Bremerton
email: lamont@a... WWW: http://www.serv.net
"Do not fear mistakes, There Are None" - Miles Davis
>RF works really badly underwater. I'd look at low-frequency audio range
>(sonar)
>
>On Wed, 22 May 2002, Jason W. Day wrote:
>
> > Anyone have an idea on how to send a wireless signal a distance of
> about 100
> > feet underwater. Does RF work under water? I just want to use a stamp and
> > send a signal to another stamp to turn on a light. Any ideas would be
> great.
> >
> > Thanks in advance,
> >
> > Jason
> >
> >
>
>Sean T. Lamont, CTO / Chief NetNerd, Abstract Software, Inc. (ServNet)
>Seattle - Bellingham - Vancouver - Portland - Everett - Tacoma - Bremerton
>email: lamont@a... WWW: http://www.serv.net
> "Do not fear mistakes, There Are None" - Miles Davis
Beau Schwabe Mask Designer IV - ATL
National Semiconductor Enterprise Networking Business Unit
500 Pinnacle Court, Suite 525 Wired Communications Division
Mail Stop GA1 Norcross, GA 30071
II's at both ends for bi-directional comms with the sub). Standard R/C
equipment typically runs about 200 mw (miliwatts) and they get acceptable
ranges of around 400' horizontal down to a depth of around 10' feet which is
WAY morte than you need as below the surface more than a few inches you
won't be able to see the boat much and at 400' feet the little subs get
mighty hard to see. RF works well in fresh water (IE: lakes, ponds), not as
well in salt water and worst of all in chlorinated water but still good
enough for R/C sub purposes..
Mike B.
Original Message
From: "Dennis P. O'Leary" <doleary@h...>
To: <basicstamps@yahoogroups.com>
Sent: Wednesday, May 22, 2002 9:03 PM
Subject: RE: [noparse][[/noparse]basicstamps] Underwater communication
> Fry's sells a low-cost model sub with RF control, that I plan to try in
> my pool here in Pasadena CA.
>
> Dennis
>
>
Original Message
> From: David Wright [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=DjjcCJk6__Glt14d38trmhbbFXIt8RoozHdAoljZmODdqNMGZrsD47ItyGS2ld5eXzF8YIquTDnqaS2eZw]dwright3@a...[/url
> Sent: Wednesday, May 22, 2002 8:04 PM
> To: basicstamps@yahoogroups.com
> Subject: Re: [noparse][[/noparse]basicstamps] Underwater communication
>
>
> Niches Werste buddy, RF underwater aint going to go far unless you
> really jack up the signal strength of which I dont think you can do.
> That is why the Navy uses Very Low Frequency signals to communicate to
> subs under water. VLF is in the 10s of hertz.
>
>
>
Original Message
> From: "Jason W. Day" <j_w_day@y...>
> To: <basicstamps@yahoogroups.com>
> Sent: Wednesday, May 22, 2002 8:11 PM
> Subject: RE: [noparse][[/noparse]basicstamps] Underwater communication
>
>
> > Anyone have an idea on how to send a wireless signal a distance of
> > about
> 100
> > feet underwater. Does RF work under water? I just want to use a stamp
> > and send a signal to another stamp to turn on a light. Any ideas would
>
> > be
> great.
> >
> > Thanks in advance,
> >
> > Jason
> >
> >
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> > from the same email address that you subscribed. Text in the Subject
> > and
> Body of the message will be ignored.
> >
> >
> > Your use of Yahoo! Groups is subject to
> > http://docs.yahoo.com/info/terms/
> >
> >
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject
> and Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
>
>
>
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
feet at the deep end with a clear view of the bottom.
Thanks, Mike
Dennis
Original Message
From: Mike Blier [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=9ijt5ThxBuaYHamLwiWFhUKZaiNZNqMIl6hypH7its4PoDwNk692DK1X91NYN8uY_9FBEGQMQJgM]w6ffc@p...[/url
Sent: Thursday, May 23, 2002 2:09 PM
To: basicstamps@yahoogroups.com
Subject: Re: [noparse][[/noparse]basicstamps] Underwater communication
I am currently building a R/C sub (11' 3" lomg, 12" diameter, using
Stamp II's at both ends for bi-directional comms with the sub).
Standard R/C equipment typically runs about 200 mw (miliwatts) and they
get acceptable ranges of around 400' horizontal down to a depth of
around 10' feet which is WAY morte than you need as below the surface
more than a few inches you won't be able to see the boat much and at
400' feet the little subs get mighty hard to see. RF works well in
fresh water (IE: lakes, ponds), not as well in salt water and worst of
all in chlorinated water but still good enough for R/C sub purposes..
Mike B.
Original Message
From: "Dennis P. O'Leary" <doleary@h...>
To: <basicstamps@yahoogroups.com>
Sent: Wednesday, May 22, 2002 9:03 PM
Subject: RE: [noparse][[/noparse]basicstamps] Underwater communication
> Fry's sells a low-cost model sub with RF control, that I plan to try
> in my pool here in Pasadena CA.
>
> Dennis
<deleted>
The only RF frequencies that may work at all is the very low frequencies at
160 khz or less. These frequencies are used by submarines to about 60 feet
below the surface.
Frank
>
Original Message
> From: Jason W. Day [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=ZomQOv1z38Agrc8FKrZKPiK5mSuHHhHg2if43HQDsq6QMzhdu1Wwejs6W9DovF0amXfCM6b8-HM]j_w_day@y...[/url
> Sent: Wednesday, May 22, 2002 9:12 PM
> To: basicstamps@yahoogroups.com
> Subject: RE: [noparse][[/noparse]basicstamps] Underwater communication
>
>
> Anyone have an idea on how to send a wireless signal a distance
> of about 100
> feet underwater. Does RF work under water? I just want to use a stamp and
> send a signal to another stamp to turn on a light. Any ideas
> would be great.
>
> Thanks in advance,
>
> Jason
>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the
> Subject and Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
RF doesn't work underwater, but it
seems that it does anyway.
Take a look at this site, dedicated to the very substantial and popular hobby of
R/C submarines.
www.subcommittee.com
Maybe one of these guys could explain, in terms of wavelength, absorbance,
something physical -- why their
machines remain under good control. I know it works fine but I don't understand
why. Michael
Frank Stratton wrote:
> I'm an amateur Radio Operator and RF underwater does not work very well.
> The only RF frequencies that may work at all is the very low frequencies at
> 160 khz or less. These frequencies are used by submarines to about 60 feet
> below the surface.
>
> Frank
>
> >
Original Message
> > From: Jason W. Day [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=wEAfu8L3hlhRPyT7M1oGDjLfVFfK0ZUiYFCT4B--xwYocxCIIo66VGWhHnJNfEmdOc6cXwScYlXJzO0]j_w_day@y...[/url
> > Sent: Wednesday, May 22, 2002 9:12 PM
> > To: basicstamps@yahoogroups.com
> > Subject: RE: [noparse][[/noparse]basicstamps] Underwater communication
> >
> >
> > Anyone have an idea on how to send a wireless signal a distance
> > of about 100
> > feet underwater. Does RF work under water? I just want to use a stamp and
> > send a signal to another stamp to turn on a light. Any ideas
> > would be great.
> >
> > Thanks in advance,
> >
> > Jason
> >
> >
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> > from the same email address that you subscribed. Text in the
> > Subject and Body of the message will be ignored.
> >
> >
> > Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
> >
> >
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and Body
of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
that RF doesn't work underwater, but it
seems that it does anyway"
I wasn't offering an opinion rather I was stating fact. The R/C sub world
has been around for many, many years.(I have been involved for over 20) The
ranges we are talking about is quite short and the attentuation caused by
the radio receiver and antenna being in water is offset by the strength of
the signal from the controller.
With standard R/C equipment only operating in the 200 miliwatt range there
is still enough signal to penetrate the water for adequate control.
I am also an amateur radio operator for over 43 years and have discovered
the RF doesn't always obey the standard conventions... I will have a
considerable investment in the current sub project and so to "hedge my bets"
I will be using 420 Mhz radios (in the 70 cm amateur band) that the Stamp II
will talk to on both ends. (Bidirectional communications) The data radios
have as an output the received signal strength. With the RSSI signal I will
use it to determine the power output necessary to maintain reliable comms
with the shore unit and adjust the transmitter(s) as needed.. These radios
are programmable under Stamp II control from 50 mw to a full 5 watts output,
that will get the job done for sure.
I see you have posted the SubCommette web site link, they are a great
bunch and an excellent resource.
R/C subs are a blast and I am sure the original poster will get a great
deal of enjoyment from the hobby.
Mike B.
Original Message
From: "Michael Gianturco" <michcg@m...>
To: <basicstamps@yahoogroups.com>
Sent: Friday, May 24, 2002 8:23 AM
Subject: Re: [noparse][[/noparse]basicstamps] Underwater communication
> It is interesting to see the range of opinions on this. I was also taught
that RF doesn't work underwater, but it
> seems that it does anyway.
>
> Take a look at this site, dedicated to the very substantial and popular
hobby of R/C submarines.
>
> www.subcommittee.com
>
> Maybe one of these guys could explain, in terms of wavelength, absorbance,
something physical -- why their
> machines remain under good control. I know it works fine but I don't
understand why. Michael
>
>
>
>
> Frank Stratton wrote:
>
> > I'm an amateur Radio Operator and RF underwater does not work very well.
> > The only RF frequencies that may work at all is the very low frequencies
at
> > 160 khz or less. These frequencies are used by submarines to about 60
feet
> > below the surface.
> >
> > Frank
> >
> > >
Original Message
> > > From: Jason W. Day [noparse]/noparse]mailto:[url=http://forums.parallaxinc.com/group/basicstamps/post?postID=0p_TDb6QC_C9qHxMOd8FqJZd8TgAHTIsc1zCJuSKnVhcikRYsZ3_DS6RacVtmH_nFrTUkfcjl5OoIw]j_w_day@y...[/url
> > > Sent: Wednesday, May 22, 2002 9:12 PM
> > > To: basicstamps@yahoogroups.com
> > > Subject: RE: [noparse][[/noparse]basicstamps] Underwater communication
> > >
> > >
> > > Anyone have an idea on how to send a wireless signal a distance
> > > of about 100
> > > feet underwater. Does RF work under water? I just want to use a stamp
and
> > > send a signal to another stamp to turn on a light. Any ideas
> > > would be great.
> > >
> > > Thanks in advance,
> > >
> > > Jason
> > >
> > >
> > >
> > > To UNSUBSCRIBE, just send mail to:
> > > basicstamps-unsubscribe@yahoogroups.com
> > > from the same email address that you subscribed. Text in the
> > > Subject and Body of the message will be ignored.
> > >
> > >
> > > Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
> > >
> > >
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@yahoogroups.com
> > from the same email address that you subscribed. Text in the Subject
and Body of the message will be ignored.
> >
> >
> > Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
with 420mhz?
MIT has developed a submarine called ORCA. It states the following
in the journal paper that describes ORCA "The wireless data link is
a pair of Freewave DGRO frequency-hopping spread spectrum data
transceivers. These devices operate over the 902-928 MHz frequency
band, transmitting at 1 W. They connect to the host computer using
an RS-232 serial port and have a maximum data rate of 115 kbps/sec.
In air, they have a 20-mile line-of-sight range, but with one unit
underwater, depth becomes the limiting factor. In a chlorinated
swimming pool, the units perform well up to a depth of about 1 m.
Communication with the vehicle can also be established using a
tether which provides an Ethernet link to the computer and a live
video feed from the CCD camera."
Here is the link to the journal paper:
http://www.auvsi.org/competitions/2002/papers/MIT.pdf
--- In basicstamps@y..., Mike Blier <w6ffc@p...> wrote:
> "It is interesting to see the range of opinions on this. I was
also taught
> that RF doesn't work underwater, but it
> seems that it does anyway"
>
> I wasn't offering an opinion rather I was stating fact. The R/C
sub world
> has been around for many, many years.(I have been involved for
over 20) The
> ranges we are talking about is quite short and the attentuation
caused by
> the radio receiver and antenna being in water is offset by the
strength of
> the signal from the controller.
>
> With standard R/C equipment only operating in the 200 miliwatt
range there
> is still enough signal to penetrate the water for adequate control.
>
> I am also an amateur radio operator for over 43 years and have
discovered
> the RF doesn't always obey the standard conventions... I will
have a
> considerable investment in the current sub project and so
to "hedge my bets"
> I will be using 420 Mhz radios (in the 70 cm amateur band) that
the Stamp II
> will talk to on both ends. (Bidirectional communications) The
data radios
> have as an output the received signal strength. With the RSSI
signal I will
> use it to determine the power output necessary to maintain
reliable comms
> with the shore unit and adjust the transmitter(s) as needed..
These radios
> are programmable under Stamp II control from 50 mw to a full 5
watts output,
> that will get the job done for sure.
>
> I see you have posted the SubCommette web site link, they are a
great
> bunch and an excellent resource.
>
> R/C subs are a blast and I am sure the original poster will get
a great
> deal of enjoyment from the hobby.
>
> Mike B.
>
>
>
Original Message
> From: "Michael Gianturco" <michcg@m...>
> To: <basicstamps@y...>
> Sent: Friday, May 24, 2002 8:23 AM
> Subject: Re: [noparse][[/noparse]basicstamps] Underwater communication
>
>
> > It is interesting to see the range of opinions on this. I was
also taught
> that RF doesn't work underwater, but it
> > seems that it does anyway.
> >
> > Take a look at this site, dedicated to the very substantial and
popular
> hobby of R/C submarines.
> >
> > www.subcommittee.com
> >
> > Maybe one of these guys could explain, in terms of wavelength,
absorbance,
> something physical -- why their
> > machines remain under good control. I know it works fine but I
don't
> understand why. Michael
> >
> >
> >
> >
> > Frank Stratton wrote:
> >
> > > I'm an amateur Radio Operator and RF underwater does not work
very well.
> > > The only RF frequencies that may work at all is the very low
frequencies
> at
> > > 160 khz or less. These frequencies are used by submarines to
about 60
> feet
> > > below the surface.
> > >
> > > Frank
> > >
> > > >
Original Message
> > > > From: Jason W. Day [noparse][[/noparse]mailto:j_w_day@y...]
> > > > Sent: Wednesday, May 22, 2002 9:12 PM
> > > > To: basicstamps@y...
> > > > Subject: RE: [noparse][[/noparse]basicstamps] Underwater communication
> > > >
> > > >
> > > > Anyone have an idea on how to send a wireless signal a
distance
> > > > of about 100
> > > > feet underwater. Does RF work under water? I just want to
use a stamp
> and
> > > > send a signal to another stamp to turn on a light. Any ideas
> > > > would be great.
> > > >
> > > > Thanks in advance,
> > > >
> > > > Jason
> > > >
> > > >
> > > >
> > > > To UNSUBSCRIBE, just send mail to:
> > > > basicstamps-unsubscribe@y...
> > > > from the same email address that you subscribed. Text in the
> > > > Subject and Body of the message will be ignored.
> > > >
> > > >
> > > > Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
> > > >
> > > >
> > >
> > > To UNSUBSCRIBE, just send mail to:
> > > basicstamps-unsubscribe@y...
> > > from the same email address that you subscribed. Text in the
Subject
> and Body of the message will be ignored.
> > >
> > >
> > > Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
> >
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@y...
> > from the same email address that you subscribed. Text in the
Subject and
> Body of the message will be ignored.
> >
> >
> > Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
> >
> >
isn't a typo). http://www.oldradio.com/archives/jurassic/ELF.doc
Basically because higher frequency radio will not travel through water well
at all, they use ELF...
Problem then becomes building a receiver or transmitter...
Ben, Wellington, New Zealand.
--
http://www.lennard.net.nz/
Ben Lennard, NCEE, Dip EE
Electronics R&D - Kiwi Made, Innovative Electronics.
Hm: +64 4 972 7567
Mb: +64 21 536 627
87 Spencer Street
Crofton Downs
Wellington
New Zealand
"To the optimist, the glass is half full. To the pessimist, the glass is
half empty. To the engineer, the glass is twice as big as it needs to be."
No animals were harmed in the transmission of this email, although the
Dog next door is living on borrowed time, let me tell you! Those of you
with an overwhelming fear of the unknown will be gratified to learn that
there is no hidden message revealed by reading this warning backwards.
> From: "codepro" <codepro@y...>
> Reply-To: basicstamps@yahoogroups.com
> Date: Tue, 26 Nov 2002 23:37:55 -0000
> To: basicstamps@yahoogroups.com
> Subject: [noparse][[/noparse]basicstamps] Re: Underwater communication
>
> I am also a amateur radio operator. Mike why did you decide to go
> with 420mhz?
>
> MIT has developed a submarine called ORCA. It states the following
> in the journal paper that describes ORCA "The wireless data link is
> a pair of Freewave DGRO frequency-hopping spread spectrum data
> transceivers. These devices operate over the 902-928 MHz frequency
> band, transmitting at 1 W. They connect to the host computer using
> an RS-232 serial port and have a maximum data rate of 115 kbps/sec.
> In air, they have a 20-mile line-of-sight range, but with one unit
> underwater, depth becomes the limiting factor. In a chlorinated
> swimming pool, the units perform well up to a depth of about 1 m.
> Communication with the vehicle can also be established using a
> tether which provides an Ethernet link to the computer and a live
> video feed from the CCD camera."
>
> Here is the link to the journal paper:
> http://www.auvsi.org/competitions/2002/papers/MIT.pdf
>
> --- In basicstamps@y..., Mike Blier <w6ffc@p...> wrote:
>> "It is interesting to see the range of opinions on this. I was
> also taught
>> that RF doesn't work underwater, but it
>> seems that it does anyway"
>>
>> I wasn't offering an opinion rather I was stating fact. The R/C
> sub world
>> has been around for many, many years.(I have been involved for
> over 20) The
>> ranges we are talking about is quite short and the attentuation
> caused by
>> the radio receiver and antenna being in water is offset by the
> strength of
>> the signal from the controller.
>>
>> With standard R/C equipment only operating in the 200 miliwatt
> range there
>> is still enough signal to penetrate the water for adequate control.
>>
>> I am also an amateur radio operator for over 43 years and have
> discovered
>> the RF doesn't always obey the standard conventions... I will
> have a
>> considerable investment in the current sub project and so
> to "hedge my bets"
>> I will be using 420 Mhz radios (in the 70 cm amateur band) that
> the Stamp II
>> will talk to on both ends. (Bidirectional communications) The
> data radios
>> have as an output the received signal strength. With the RSSI
> signal I will
>> use it to determine the power output necessary to maintain
> reliable comms
>> with the shore unit and adjust the transmitter(s) as needed..
> These radios
>> are programmable under Stamp II control from 50 mw to a full 5
> watts output,
>> that will get the job done for sure.
>>
>> I see you have posted the SubCommette web site link, they are a
> great
>> bunch and an excellent resource.
>>
>> R/C subs are a blast and I am sure the original poster will get
> a great
>> deal of enjoyment from the hobby.
>>
>> Mike B.
>>
>>
>>
Original Message
>> From: "Michael Gianturco" <michcg@m...>
>> To: <basicstamps@y...>
>> Sent: Friday, May 24, 2002 8:23 AM
>> Subject: Re: [noparse][[/noparse]basicstamps] Underwater communication
>>
>>
>>> It is interesting to see the range of opinions on this. I was
> also taught
>> that RF doesn't work underwater, but it
>>> seems that it does anyway.
>>>
>>> Take a look at this site, dedicated to the very substantial and
> popular
>> hobby of R/C submarines.
>>>
>>> www.subcommittee.com
>>>
>>> Maybe one of these guys could explain, in terms of wavelength,
> absorbance,
>> something physical -- why their
>>> machines remain under good control. I know it works fine but I
> don't
>> understand why. Michael
>>>
>>>
>>>
>>>
>>> Frank Stratton wrote:
>>>
>>>> I'm an amateur Radio Operator and RF underwater does not work
> very well.
>>>> The only RF frequencies that may work at all is the very low
> frequencies
>> at
>>>> 160 khz or less. These frequencies are used by submarines to
> about 60
>> feet
>>>> below the surface.
>>>>
>>>> Frank
>>>>
>>>>>
Original Message
>>>>> From: Jason W. Day [noparse][[/noparse]mailto:j_w_day@y...]
>>>>> Sent: Wednesday, May 22, 2002 9:12 PM
>>>>> To: basicstamps@y...
>>>>> Subject: RE: [noparse][[/noparse]basicstamps] Underwater communication
>>>>>
>>>>>
>>>>> Anyone have an idea on how to send a wireless signal a
> distance
>>>>> of about 100
>>>>> feet underwater. Does RF work under water? I just want to
> use a stamp
>> and
>>>>> send a signal to another stamp to turn on a light. Any ideas
>>>>> would be great.
>>>>>
>>>>> Thanks in advance,
>>>>>
>>>>> Jason
>>>>>
>>>>>
>>>>>
>>>>> To UNSUBSCRIBE, just send mail to:
>>>>> basicstamps-unsubscribe@y...
>>>>> from the same email address that you subscribed. Text in the
>>>>> Subject and Body of the message will be ignored.
>>>>>
>>>>>
>>>>> Your use of Yahoo! Groups is subject to
>> http://docs.yahoo.com/info/terms/
>>>>>
>>>>>
>>>>
>>>> To UNSUBSCRIBE, just send mail to:
>>>> basicstamps-unsubscribe@y...
>>>> from the same email address that you subscribed. Text in the
> Subject
>> and Body of the message will be ignored.
>>>>
>>>>
>>>> Your use of Yahoo! Groups is subject to
>> http://docs.yahoo.com/info/terms/
>>>
>>>
>>> To UNSUBSCRIBE, just send mail to:
>>> basicstamps-unsubscribe@y...
>>> from the same email address that you subscribed. Text in the
> Subject and
>> Body of the message will be ignored.
>>>
>>>
>>> Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
>>>
>>>
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and Body
> of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
about ELF for some time, but not those details. The article although
does not mention the problems with sending sound through water. Here
is a link to a World War II Submarine Sonar operator's manual that
talks about what happens to sound when sent through water:
http://www.maritime.org/fleetsub/sonar/chap3.htm#3A
Here is a link to the full manual:
http://www.maritime.org/fleetsub/sonar/index.htm
There are a number of underwater acoustic modems on the market,
listed below is a link to one that can supposedly do 28k baud with a
maximum range of 6 km. Unless you own a oil platform you probably
won't be able to afford it.
http://www.bmt-wismar.de/bmteng/modem_en.html
Here is link to a college paper that talks about what's needed to
build a underwater acoustic modem:
http://guinness.cs.stevens-tech.edu/~mtalreja/seniord/
If anyone is serious about building one, let me know. I can help out
in programming, but my knowledge of EE is limited.
--- In basicstamps@y..., Ben <ben@l...> wrote:
> For underwater comms, Military Subs use ELF. ie - from 30Hz to
300Hz (that
> isn't a typo). http://www.oldradio.com/archives/jurassic/ELF.doc
>
> Basically because higher frequency radio will not travel through
water well
> at all, they use ELF...
>
> Problem then becomes building a receiver or transmitter...
>
>
> Ben, Wellington, New Zealand.
> --
>
> http://www.lennard.net.nz/
> Ben Lennard, NCEE, Dip EE
>
> Electronics R&D - Kiwi Made, Innovative Electronics.
>
> Hm: +64 4 972 7567
> Mb: +64 21 536 627
> 87 Spencer Street
> Crofton Downs
> Wellington
> New Zealand
>
> "To the optimist, the glass is half full. To the pessimist, the
glass is
> half empty. To the engineer, the glass is twice as big as it needs
to be."
>
> No animals were harmed in the transmission of this email, although
the
> Dog next door is living on borrowed time, let me tell you! Those
of you
> with an overwhelming fear of the unknown will be gratified to learn
that
> there is no hidden message revealed by reading this warning
backwards.
>
> > From: "codepro" <codepro@y...>
> > Reply-To: basicstamps@y...
> > Date: Tue, 26 Nov 2002 23:37:55 -0000
> > To: basicstamps@y...
> > Subject: [noparse][[/noparse]basicstamps] Re: Underwater communication
> >
> > I am also a amateur radio operator. Mike why did you decide to go
> > with 420mhz?
> >
> > MIT has developed a submarine called ORCA. It states the
following
> > in the journal paper that describes ORCA "The wireless data link
is
> > a pair of Freewave DGRO frequency-hopping spread spectrum data
> > transceivers. These devices operate over the 902-928 MHz frequency
> > band, transmitting at 1 W. They connect to the host computer using
> > an RS-232 serial port and have a maximum data rate of 115
kbps/sec.
> > In air, they have a 20-mile line-of-sight range, but with one unit
> > underwater, depth becomes the limiting factor. In a chlorinated
> > swimming pool, the units perform well up to a depth of about 1 m.
> > Communication with the vehicle can also be established using a
> > tether which provides an Ethernet link to the computer and a live
> > video feed from the CCD camera."
> >
> > Here is the link to the journal paper:
> > http://www.auvsi.org/competitions/2002/papers/MIT.pdf
> >
> > --- In basicstamps@y..., Mike Blier <w6ffc@p...> wrote:
> >> "It is interesting to see the range of opinions on this. I was
> > also taught
> >> that RF doesn't work underwater, but it
> >> seems that it does anyway"
> >>
> >> I wasn't offering an opinion rather I was stating fact. The R/C
> > sub world
> >> has been around for many, many years.(I have been involved for
> > over 20) The
> >> ranges we are talking about is quite short and the attentuation
> > caused by
> >> the radio receiver and antenna being in water is offset by the
> > strength of
> >> the signal from the controller.
> >>
> >> With standard R/C equipment only operating in the 200 miliwatt
> > range there
> >> is still enough signal to penetrate the water for adequate
control.
> >>
> >> I am also an amateur radio operator for over 43 years and have
> > discovered
> >> the RF doesn't always obey the standard conventions... I will
> > have a
> >> considerable investment in the current sub project and so
> > to "hedge my bets"
> >> I will be using 420 Mhz radios (in the 70 cm amateur band) that
> > the Stamp II
> >> will talk to on both ends. (Bidirectional communications) The
> > data radios
> >> have as an output the received signal strength. With the RSSI
> > signal I will
> >> use it to determine the power output necessary to maintain
> > reliable comms
> >> with the shore unit and adjust the transmitter(s) as needed..
> > These radios
> >> are programmable under Stamp II control from 50 mw to a full 5
> > watts output,
> >> that will get the job done for sure.
> >>
> >> I see you have posted the SubCommette web site link, they are a
> > great
> >> bunch and an excellent resource.
> >>
> >> R/C subs are a blast and I am sure the original poster will get
> > a great
> >> deal of enjoyment from the hobby.
> >>
> >> Mike B.
> >>
> >>
> >>
Original Message
> >> From: "Michael Gianturco" <michcg@m...>
> >> To: <basicstamps@y...>
> >> Sent: Friday, May 24, 2002 8:23 AM
> >> Subject: Re: [noparse][[/noparse]basicstamps] Underwater communication
> >>
> >>
> >>> It is interesting to see the range of opinions on this. I was
> > also taught
> >> that RF doesn't work underwater, but it
> >>> seems that it does anyway.
> >>>
> >>> Take a look at this site, dedicated to the very substantial and
> > popular
> >> hobby of R/C submarines.
> >>>
> >>> www.subcommittee.com
> >>>
> >>> Maybe one of these guys could explain, in terms of wavelength,
> > absorbance,
> >> something physical -- why their
> >>> machines remain under good control. I know it works fine but I
> > don't
> >> understand why. Michael
> >>>
> >>>
> >>>
> >>>
> >>> Frank Stratton wrote:
> >>>
> >>>> I'm an amateur Radio Operator and RF underwater does not work
> > very well.
> >>>> The only RF frequencies that may work at all is the very low
> > frequencies
> >> at
> >>>> 160 khz or less. These frequencies are used by submarines to
> > about 60
> >> feet
> >>>> below the surface.
> >>>>
> >>>> Frank
> >>>>
> >>>>>
Original Message
> >>>>> From: Jason W. Day [noparse][[/noparse]mailto:j_w_day@y...]
> >>>>> Sent: Wednesday, May 22, 2002 9:12 PM
> >>>>> To: basicstamps@y...
> >>>>> Subject: RE: [noparse][[/noparse]basicstamps] Underwater communication
> >>>>>
> >>>>>
> >>>>> Anyone have an idea on how to send a wireless signal a
> > distance
> >>>>> of about 100
> >>>>> feet underwater. Does RF work under water? I just want to
> > use a stamp
> >> and
> >>>>> send a signal to another stamp to turn on a light. Any ideas
> >>>>> would be great.
> >>>>>
> >>>>> Thanks in advance,
> >>>>>
> >>>>> Jason
> >>>>>
> >>>>>
> >>>>>
> >>>>> To UNSUBSCRIBE, just send mail to:
> >>>>> basicstamps-unsubscribe@y...
> >>>>> from the same email address that you subscribed. Text in the
> >>>>> Subject and Body of the message will be ignored.
> >>>>>
> >>>>>
> >>>>> Your use of Yahoo! Groups is subject to
> >> http://docs.yahoo.com/info/terms/
> >>>>>
> >>>>>
> >>>>
> >>>> To UNSUBSCRIBE, just send mail to:
> >>>> basicstamps-unsubscribe@y...
> >>>> from the same email address that you subscribed. Text in the
> > Subject
> >> and Body of the message will be ignored.
> >>>>
> >>>>
> >>>> Your use of Yahoo! Groups is subject to
> >> http://docs.yahoo.com/info/terms/
> >>>
> >>>
> >>> To UNSUBSCRIBE, just send mail to:
> >>> basicstamps-unsubscribe@y...
> >>> from the same email address that you subscribed. Text in the
> > Subject and
> >> Body of the message will be ignored.
> >>>
> >>>
> >>> Your use of Yahoo! Groups is subject to
> > http://docs.yahoo.com/info/terms/
> >>>
> >>>
> >
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@y...
> > from the same email address that you subscribed. Text in the
Subject and Body
> > of the message will be ignored.
> >
> >
> > Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
> >
> >
communications". Much of it refers to acoustic messaging.
You might try some simple experiments with underwater low speed tone
transmissions between two loudspeaker in plastic bags for waterproofing - a
fun experiment at bathtime!
Someone may already have experimented with free-air acoustic digital
transmission, so there may already be stuff around that you could adapt.
For experimenting, you could use one loudspeaker as the sender, and the
other acting as a pickup.
The sending side is relatively simple. The receive side will need a low
impedance audio amp and a system to turn a recognised tone into a 5V signal.
Do a search on google for circuits on the NE 567 PLL. For best results you
should use one tone for sending binary 0 and one tone for binary 1. So you
will need one low-impedance pre-amp and two tone converters.
Getit working in free air to start with to prove it works (nice and noisy) ,
then underwater. Try it with one tone at a time at first, and try finding
two seperate frequencies well apart that work well.
Regards,
Tony
Original Message
From: "codepro" <codepro@y...>
To: <basicstamps@yahoogroups.com>
Sent: Wednesday, November 27, 2002 9:46 AM
Subject: [noparse][[/noparse]basicstamps] Re: Underwater communication
> Ben, thanks for that link, it's an interesting article. I've know
> about ELF for some time, but not those details. The article although
> does not mention the problems with sending sound through water. Here
> is a link to a World War II Submarine Sonar operator's manual that
> talks about what happens to sound when sent through water:
> http://www.maritime.org/fleetsub/sonar/chap3.htm#3A
>
> Here is a link to the full manual:
> http://www.maritime.org/fleetsub/sonar/index.htm
>
> There are a number of underwater acoustic modems on the market,
> listed below is a link to one that can supposedly do 28k baud with a
> maximum range of 6 km. Unless you own a oil platform you probably
> won't be able to afford it.
> http://www.bmt-wismar.de/bmteng/modem_en.html
>
> Here is link to a college paper that talks about what's needed to
> build a underwater acoustic modem:
> http://guinness.cs.stevens-tech.edu/~mtalreja/seniord/
>
> If anyone is serious about building one, let me know. I can help out
> in programming, but my knowledge of EE is limited.
>
> --- In basicstamps@y..., Ben <ben@l...> wrote:
> > For underwater comms, Military Subs use ELF. ie - from 30Hz to
> 300Hz (that
> > isn't a typo). http://www.oldradio.com/archives/jurassic/ELF.doc
> >
> > Basically because higher frequency radio will not travel through
> water well
> > at all, they use ELF...
> >
> > Problem then becomes building a receiver or transmitter...
> >
> >
> > Ben, Wellington, New Zealand.
> > --
> >
> > http://www.lennard.net.nz/
> > Ben Lennard, NCEE, Dip EE
> >
> > Electronics R&D - Kiwi Made, Innovative Electronics.
> >
> > Hm: +64 4 972 7567
> > Mb: +64 21 536 627
> > 87 Spencer Street
> > Crofton Downs
> > Wellington
> > New Zealand
> >
> > "To the optimist, the glass is half full. To the pessimist, the
> glass is
> > half empty. To the engineer, the glass is twice as big as it needs
> to be."
> >
> > No animals were harmed in the transmission of this email, although
> the
> > Dog next door is living on borrowed time, let me tell you! Those
> of you
> > with an overwhelming fear of the unknown will be gratified to learn
> that
> > there is no hidden message revealed by reading this warning
> backwards.
> >
> > > From: "codepro" <codepro@y...>
> > > Reply-To: basicstamps@y...
> > > Date: Tue, 26 Nov 2002 23:37:55 -0000
> > > To: basicstamps@y...
> > > Subject: [noparse][[/noparse]basicstamps] Re: Underwater communication
> > >
> > > I am also a amateur radio operator. Mike why did you decide to go
> > > with 420mhz?
> > >
> > > MIT has developed a submarine called ORCA. It states the
> following
> > > in the journal paper that describes ORCA "The wireless data link
> is
> > > a pair of Freewave DGRO frequency-hopping spread spectrum data
> > > transceivers. These devices operate over the 902-928 MHz frequency
> > > band, transmitting at 1 W. They connect to the host computer using
> > > an RS-232 serial port and have a maximum data rate of 115
> kbps/sec.
> > > In air, they have a 20-mile line-of-sight range, but with one unit
> > > underwater, depth becomes the limiting factor. In a chlorinated
> > > swimming pool, the units perform well up to a depth of about 1 m.
> > > Communication with the vehicle can also be established using a
> > > tether which provides an Ethernet link to the computer and a live
> > > video feed from the CCD camera."
> > >
> > > Here is the link to the journal paper:
> > > http://www.auvsi.org/competitions/2002/papers/MIT.pdf
> > >
> > > --- In basicstamps@y..., Mike Blier <w6ffc@p...> wrote:
> > >> "It is interesting to see the range of opinions on this. I was
> > > also taught
> > >> that RF doesn't work underwater, but it
> > >> seems that it does anyway"
> > >>
> > >> I wasn't offering an opinion rather I was stating fact. The R/C
> > > sub world
> > >> has been around for many, many years.(I have been involved for
> > > over 20) The
> > >> ranges we are talking about is quite short and the attentuation
> > > caused by
> > >> the radio receiver and antenna being in water is offset by the
> > > strength of
> > >> the signal from the controller.
> > >>
> > >> With standard R/C equipment only operating in the 200 miliwatt
> > > range there
> > >> is still enough signal to penetrate the water for adequate
> control.
> > >>
> > >> I am also an amateur radio operator for over 43 years and have
> > > discovered
> > >> the RF doesn't always obey the standard conventions... I will
> > > have a
> > >> considerable investment in the current sub project and so
> > > to "hedge my bets"
> > >> I will be using 420 Mhz radios (in the 70 cm amateur band) that
> > > the Stamp II
> > >> will talk to on both ends. (Bidirectional communications) The
> > > data radios
> > >> have as an output the received signal strength. With the RSSI
> > > signal I will
> > >> use it to determine the power output necessary to maintain
> > > reliable comms
> > >> with the shore unit and adjust the transmitter(s) as needed..
> > > These radios
> > >> are programmable under Stamp II control from 50 mw to a full 5
> > > watts output,
> > >> that will get the job done for sure.
> > >>
> > >> I see you have posted the SubCommette web site link, they are a
> > > great
> > >> bunch and an excellent resource.
> > >>
> > >> R/C subs are a blast and I am sure the original poster will get
> > > a great
> > >> deal of enjoyment from the hobby.
> > >>
> > >> Mike B.
> > >>
> > >>
> > >>
Original Message
> > >> From: "Michael Gianturco" <michcg@m...>
> > >> To: <basicstamps@y...>
> > >> Sent: Friday, May 24, 2002 8:23 AM
> > >> Subject: Re: [noparse][[/noparse]basicstamps] Underwater communication
> > >>
> > >>
> > >>> It is interesting to see the range of opinions on this. I was
> > > also taught
> > >> that RF doesn't work underwater, but it
> > >>> seems that it does anyway.
> > >>>
> > >>> Take a look at this site, dedicated to the very substantial and
> > > popular
> > >> hobby of R/C submarines.
> > >>>
> > >>> www.subcommittee.com
> > >>>
> > >>> Maybe one of these guys could explain, in terms of wavelength,
> > > absorbance,
> > >> something physical -- why their
> > >>> machines remain under good control. I know it works fine but I
> > > don't
> > >> understand why. Michael
> > >>>
> > >>>
> > >>>
> > >>>
> > >>> Frank Stratton wrote:
> > >>>
> > >>>> I'm an amateur Radio Operator and RF underwater does not work
> > > very well.
> > >>>> The only RF frequencies that may work at all is the very low
> > > frequencies
> > >> at
> > >>>> 160 khz or less. These frequencies are used by submarines to
> > > about 60
> > >> feet
> > >>>> below the surface.
> > >>>>
> > >>>> Frank
> > >>>>
> > >>>>>
Original Message
> > >>>>> From: Jason W. Day [noparse][[/noparse]mailto:j_w_day@y...]
> > >>>>> Sent: Wednesday, May 22, 2002 9:12 PM
> > >>>>> To: basicstamps@y...
> > >>>>> Subject: RE: [noparse][[/noparse]basicstamps] Underwater communication
> > >>>>>
> > >>>>>
> > >>>>> Anyone have an idea on how to send a wireless signal a
> > > distance
> > >>>>> of about 100
> > >>>>> feet underwater. Does RF work under water? I just want to
> > > use a stamp
> > >> and
> > >>>>> send a signal to another stamp to turn on a light. Any ideas
> > >>>>> would be great.
> > >>>>>
> > >>>>> Thanks in advance,
> > >>>>>
> > >>>>> Jason
> > >>>>>
> > >>>>>
> > >>>>>
> > >>>>> To UNSUBSCRIBE, just send mail to:
> > >>>>> basicstamps-unsubscribe@y...
> > >>>>> from the same email address that you subscribed. Text in the
> > >>>>> Subject and Body of the message will be ignored.
> > >>>>>
> > >>>>>
> > >>>>> Your use of Yahoo! Groups is subject to
> > >> http://docs.yahoo.com/info/terms/
> > >>>>>
> > >>>>>
> > >>>>
> > >>>> To UNSUBSCRIBE, just send mail to:
> > >>>> basicstamps-unsubscribe@y...
> > >>>> from the same email address that you subscribed. Text in the
> > > Subject
> > >> and Body of the message will be ignored.
> > >>>>
> > >>>>
> > >>>> Your use of Yahoo! Groups is subject to
> > >> http://docs.yahoo.com/info/terms/
> > >>>
> > >>>
> > >>> To UNSUBSCRIBE, just send mail to:
> > >>> basicstamps-unsubscribe@y...
> > >>> from the same email address that you subscribed. Text in the
> > > Subject and
> > >> Body of the message will be ignored.
> > >>>
> > >>>
> > >>> Your use of Yahoo! Groups is subject to
> > > http://docs.yahoo.com/info/terms/
> > >>>
> > >>>
> > >
> > >
> > > To UNSUBSCRIBE, just send mail to:
> > > basicstamps-unsubscribe@y...
> > > from the same email address that you subscribed. Text in the
> Subject and Body
> > > of the message will be ignored.
> > >
> > >
> > > Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
> > >
> > >
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>
> in programming, but my knowledge of EE is limited.
>
An interesting thread....I'm curious as to why & how it began in May and
continued in November.?!
If anyone is interested in an uderwater comm project with some experience in
this sort of thing and some EE know-how, please let me know. I have a
project I've wanted to do for some time and would not mind having a partner
on it....
Chris
I'm not sure how well a loundspeaker would work at sending and
receiving sound underwater, if at all. To receive and send sound
waves in the water a device called a hydrophone is used. The World
War II Submarine operator's manual listed in a previous reply below
describes the device. Also the follow link to the Association for
Unmanned Vehicle Systems International (AUVSI) has journal papers
that describes the use of a hydrophone for detecting ping signals:
http://www.auvsi.org/competitions/2002/journal.cfm
--- In basicstamps@y..., tony.wells@a... wrote:
> Yes, there'se a lot of info around on google under "underwater
digital
> communications". Much of it refers to acoustic messaging.
>
> You might try some simple experiments with underwater low speed tone
> transmissions between two loudspeaker in plastic bags for
waterproofing - a
> fun experiment at bathtime!
>
> Someone may already have experimented with free-air acoustic digital
> transmission, so there may already be stuff around that you could
adapt.
>
> For experimenting, you could use one loudspeaker as the sender,
and the
> other acting as a pickup.
>
> The sending side is relatively simple. The receive side will need a
low
> impedance audio amp and a system to turn a recognised tone into a
5V signal.
> Do a search on google for circuits on the NE 567 PLL. For best
results you
> should use one tone for sending binary 0 and one tone for binary 1.
So you
> will need one low-impedance pre-amp and two tone converters.
>
> Getit working in free air to start with to prove it works (nice and
noisy) ,
> then underwater. Try it with one tone at a time at first, and try
finding
> two seperate frequencies well apart that work well.
>
> Regards,
>
> Tony
>
>
Original Message
> From: "codepro" <codepro@y...>
> To: <basicstamps@y...>
> Sent: Wednesday, November 27, 2002 9:46 AM
> Subject: [noparse][[/noparse]basicstamps] Re: Underwater communication
>
>
> > Ben, thanks for that link, it's an interesting article. I've know
> > about ELF for some time, but not those details. The article
although
> > does not mention the problems with sending sound through water.
Here
> > is a link to a World War II Submarine Sonar operator's manual that
> > talks about what happens to sound when sent through water:
> > http://www.maritime.org/fleetsub/sonar/chap3.htm#3A
> >
> > Here is a link to the full manual:
> > http://www.maritime.org/fleetsub/sonar/index.htm
> >
> > There are a number of underwater acoustic modems on the market,
> > listed below is a link to one that can supposedly do 28k baud
with a
> > maximum range of 6 km. Unless you own a oil platform you probably
> > won't be able to afford it.
> > http://www.bmt-wismar.de/bmteng/modem_en.html
> >
> > Here is link to a college paper that talks about what's needed to
> > build a underwater acoustic modem:
> > http://guinness.cs.stevens-tech.edu/~mtalreja/seniord/
> >
> > If anyone is serious about building one, let me know. I can help
out
> > in programming, but my knowledge of EE is limited.
> >
> > --- In basicstamps@y..., Ben <ben@l...> wrote:
> > > For underwater comms, Military Subs use ELF. ie - from 30Hz to
> > 300Hz (that
> > > isn't a typo).
http://www.oldradio.com/archives/jurassic/ELF.doc
> > >
> > > Basically because higher frequency radio will not travel through
> > water well
> > > at all, they use ELF...
> > >
> > > Problem then becomes building a receiver or transmitter...
> > >
> > >
> > > Ben, Wellington, New Zealand.
> > > --
> > >
> > > http://www.lennard.net.nz/
> > > Ben Lennard, NCEE, Dip EE
> > >
> > > Electronics R&D - Kiwi Made, Innovative Electronics.
> > >
> > > Hm: +64 4 972 7567
> > > Mb: +64 21 536 627
> > > 87 Spencer Street
> > > Crofton Downs
> > > Wellington
> > > New Zealand
> > >
> > > "To the optimist, the glass is half full. To the pessimist, the
> > glass is
> > > half empty. To the engineer, the glass is twice as big as it
needs
> > to be."
> > >
> > > No animals were harmed in the transmission of this email,
although
> > the
> > > Dog next door is living on borrowed time, let me tell you!
Those
> > of you
> > > with an overwhelming fear of the unknown will be gratified to
learn
> > that
> > > there is no hidden message revealed by reading this warning
> > backwards.
> > >
> > > > From: "codepro" <codepro@y...>
> > > > Reply-To: basicstamps@y...
> > > > Date: Tue, 26 Nov 2002 23:37:55 -0000
> > > > To: basicstamps@y...
> > > > Subject: [noparse][[/noparse]basicstamps] Re: Underwater communication
> > > >
> > > > I am also a amateur radio operator. Mike why did you decide
to go
> > > > with 420mhz?
> > > >
> > > > MIT has developed a submarine called ORCA. It states the
> > following
> > > > in the journal paper that describes ORCA "The wireless data
link
> > is
> > > > a pair of Freewave DGRO frequency-hopping spread spectrum data
> > > > transceivers. These devices operate over the 902-928 MHz
frequency
> > > > band, transmitting at 1 W. They connect to the host computer
using
> > > > an RS-232 serial port and have a maximum data rate of 115
> > kbps/sec.
> > > > In air, they have a 20-mile line-of-sight range, but with one
unit
> > > > underwater, depth becomes the limiting factor. In a
chlorinated
> > > > swimming pool, the units perform well up to a depth of about
1 m.
> > > > Communication with the vehicle can also be established using a
> > > > tether which provides an Ethernet link to the computer and a
live
> > > > video feed from the CCD camera."
> > > >
> > > > Here is the link to the journal paper:
> > > > http://www.auvsi.org/competitions/2002/papers/MIT.pdf
> > > >
> > > > --- In basicstamps@y..., Mike Blier <w6ffc@p...> wrote:
> > > >> "It is interesting to see the range of opinions on this. I
was
> > > > also taught
> > > >> that RF doesn't work underwater, but it
> > > >> seems that it does anyway"
> > > >>
> > > >> I wasn't offering an opinion rather I was stating fact. The
R/C
> > > > sub world
> > > >> has been around for many, many years.(I have been involved
for
> > > > over 20) The
> > > >> ranges we are talking about is quite short and the
attentuation
> > > > caused by
> > > >> the radio receiver and antenna being in water is offset by
the
> > > > strength of
> > > >> the signal from the controller.
> > > >>
> > > >> With standard R/C equipment only operating in the 200
miliwatt
> > > > range there
> > > >> is still enough signal to penetrate the water for adequate
> > control.
> > > >>
> > > >> I am also an amateur radio operator for over 43 years and
have
> > > > discovered
> > > >> the RF doesn't always obey the standard conventions... I
will
> > > > have a
> > > >> considerable investment in the current sub project and so
> > > > to "hedge my bets"
> > > >> I will be using 420 Mhz radios (in the 70 cm amateur band)
that
> > > > the Stamp II
> > > >> will talk to on both ends. (Bidirectional communications)
The
> > > > data radios
> > > >> have as an output the received signal strength. With the
RSSI
> > > > signal I will
> > > >> use it to determine the power output necessary to maintain
> > > > reliable comms
> > > >> with the shore unit and adjust the transmitter(s) as needed..
> > > > These radios
> > > >> are programmable under Stamp II control from 50 mw to a full
5
> > > > watts output,
> > > >> that will get the job done for sure.
> > > >>
> > > >> I see you have posted the SubCommette web site link, they
are a
> > > > great
> > > >> bunch and an excellent resource.
> > > >>
> > > >> R/C subs are a blast and I am sure the original poster will
get
> > > > a great
> > > >> deal of enjoyment from the hobby.
> > > >>
> > > >> Mike B.
> > > >>
> > > >>
> > > >>
Original Message
> > > >> From: "Michael Gianturco" <michcg@m...>
> > > >> To: <basicstamps@y...>
> > > >> Sent: Friday, May 24, 2002 8:23 AM
> > > >> Subject: Re: [noparse][[/noparse]basicstamps] Underwater communication
> > > >>
> > > >>
> > > >>> It is interesting to see the range of opinions on this. I
was
> > > > also taught
> > > >> that RF doesn't work underwater, but it
> > > >>> seems that it does anyway.
> > > >>>
> > > >>> Take a look at this site, dedicated to the very substantial
and
> > > > popular
> > > >> hobby of R/C submarines.
> > > >>>
> > > >>> www.subcommittee.com
> > > >>>
> > > >>> Maybe one of these guys could explain, in terms of
wavelength,
> > > > absorbance,
> > > >> something physical -- why their
> > > >>> machines remain under good control. I know it works fine
but I
> > > > don't
> > > >> understand why. Michael
> > > >>>
> > > >>>
> > > >>>
> > > >>>
> > > >>> Frank Stratton wrote:
> > > >>>
> > > >>>> I'm an amateur Radio Operator and RF underwater does not
work
> > > > very well.
> > > >>>> The only RF frequencies that may work at all is the very
low
> > > > frequencies
> > > >> at
> > > >>>> 160 khz or less. These frequencies are used by submarines
to
> > > > about 60
> > > >> feet
> > > >>>> below the surface.
> > > >>>>
> > > >>>> Frank
> > > >>>>
> > > >>>>>
Original Message
> > > >>>>> From: Jason W. Day [noparse][[/noparse]mailto:j_w_day@y...]
> > > >>>>> Sent: Wednesday, May 22, 2002 9:12 PM
> > > >>>>> To: basicstamps@y...
> > > >>>>> Subject: RE: [noparse][[/noparse]basicstamps] Underwater communication
> > > >>>>>
> > > >>>>>
> > > >>>>> Anyone have an idea on how to send a wireless signal a
> > > > distance
> > > >>>>> of about 100
> > > >>>>> feet underwater. Does RF work under water? I just want to
> > > > use a stamp
> > > >> and
> > > >>>>> send a signal to another stamp to turn on a light. Any
ideas
> > > >>>>> would be great.
> > > >>>>>
> > > >>>>> Thanks in advance,
> > > >>>>>
> > > >>>>> Jason
> > > >>>>>
> > > >>>>>
> > > >>>>>
> > > >>>>> To UNSUBSCRIBE, just send mail to:
> > > >>>>> basicstamps-unsubscribe@y...
> > > >>>>> from the same email address that you subscribed. Text in
the
> > > >>>>> Subject and Body of the message will be ignored.
> > > >>>>>
> > > >>>>>
> > > >>>>> Your use of Yahoo! Groups is subject to
> > > >> http://docs.yahoo.com/info/terms/
> > > >>>>>
> > > >>>>>
> > > >>>>
> > > >>>> To UNSUBSCRIBE, just send mail to:
> > > >>>> basicstamps-unsubscribe@y...
> > > >>>> from the same email address that you subscribed. Text in
the
> > > > Subject
> > > >> and Body of the message will be ignored.
> > > >>>>
> > > >>>>
> > > >>>> Your use of Yahoo! Groups is subject to
> > > >> http://docs.yahoo.com/info/terms/
> > > >>>
> > > >>>
> > > >>> To UNSUBSCRIBE, just send mail to:
> > > >>> basicstamps-unsubscribe@y...
> > > >>> from the same email address that you subscribed. Text in
the
> > > > Subject and
> > > >> Body of the message will be ignored.
> > > >>>
> > > >>>
> > > >>> Your use of Yahoo! Groups is subject to
> > > > http://docs.yahoo.com/info/terms/
> > > >>>
> > > >>>
> > > >
> > > >
> > > > To UNSUBSCRIBE, just send mail to:
> > > > basicstamps-unsubscribe@y...
> > > > from the same email address that you subscribed. Text in the
> > Subject and Body
> > > > of the message will be ignored.
> > > >
> > > >
> > > > Your use of Yahoo! Groups is subject to
> > http://docs.yahoo.com/info/terms/
> > > >
> > > >
> >
> >
> > To UNSUBSCRIBE, just send mail to:
> > basicstamps-unsubscribe@y...
> > from the same email address that you subscribed. Text in the
Subject and
> Body of the message will be ignored.
> >
> >
> > Your use of Yahoo! Groups is subject to
http://docs.yahoo.com/info/terms/
> >
> >
> >
http://sonar-fs.lboro.ac.uk/uag/products/products_hydrophone.html
--- In basicstamps@y..., "codepro" <codepro@y...> wrote:
> Tony, thanks for the info. The simple tone is a good idea,
although
> I'm not sure how well a loundspeaker would work at sending and
> receiving sound underwater, if at all. To receive and send sound
> waves in the water a device called a hydrophone is used. The World
> War II Submarine operator's manual listed in a previous reply below
> describes the device. Also the follow link to the Association for
> Unmanned Vehicle Systems International (AUVSI) has journal papers
> that describes the use of a hydrophone for detecting ping signals:
> http://www.auvsi.org/competitions/2002/journal.cfm
>
> --- In basicstamps@y..., tony.wells@a... wrote:
> > Yes, there'se a lot of info around on google under "underwater
> digital
> > communications". Much of it refers to acoustic messaging.
> >
> > You might try some simple experiments with underwater low speed
tone
> > transmissions between two loudspeaker in plastic bags for
> waterproofing - a
> > fun experiment at bathtime!
> >
> > Someone may already have experimented with free-air acoustic
digital
> > transmission, so there may already be stuff around that you could
> adapt.
> >
> > For experimenting, you could use one loudspeaker as the sender,
> and the
> > other acting as a pickup.
> >
> > The sending side is relatively simple. The receive side will need
a
> low
> > impedance audio amp and a system to turn a recognised tone into a
> 5V signal.
> > Do a search on google for circuits on the NE 567 PLL. For best
> results you
> > should use one tone for sending binary 0 and one tone for binary
1.
> So you
> > will need one low-impedance pre-amp and two tone converters.
> >
> > Getit working in free air to start with to prove it works (nice
and
> noisy) ,
> > then underwater. Try it with one tone at a time at first, and
try
> finding
> > two seperate frequencies well apart that work well.
> >
> > Regards,
> >
> > Tony
> >
> >
Original Message
> > From: "codepro" <codepro@y...>
> > To: <basicstamps@y...>
> > Sent: Wednesday, November 27, 2002 9:46 AM
> > Subject: [noparse][[/noparse]basicstamps] Re: Underwater communication
> >
> >
> > > Ben, thanks for that link, it's an interesting article. I've
know
> > > about ELF for some time, but not those details. The article
> although
> > > does not mention the problems with sending sound through
water.
> Here
> > > is a link to a World War II Submarine Sonar operator's manual
that
> > > talks about what happens to sound when sent through water:
> > > http://www.maritime.org/fleetsub/sonar/chap3.htm#3A
> > >
> > > Here is a link to the full manual:
> > > http://www.maritime.org/fleetsub/sonar/index.htm
> > >
> > > There are a number of underwater acoustic modems on the market,
> > > listed below is a link to one that can supposedly do 28k baud
> with a
> > > maximum range of 6 km. Unless you own a oil platform you
probably
> > > won't be able to afford it.
> > > http://www.bmt-wismar.de/bmteng/modem_en.html
> > >
> > > Here is link to a college paper that talks about what's needed
to
> > > build a underwater acoustic modem:
> > > http://guinness.cs.stevens-tech.edu/~mtalreja/seniord/
> > >
> > > If anyone is serious about building one, let me know. I can
help
> out
> > > in programming, but my knowledge of EE is limited.
> > >
> > > --- In basicstamps@y..., Ben <ben@l...> wrote:
> > > > For underwater comms, Military Subs use ELF. ie - from 30Hz
to
> > > 300Hz (that
> > > > isn't a typo).
> http://www.oldradio.com/archives/jurassic/ELF.doc
> > > >
> > > > Basically because higher frequency radio will not travel
through
> > > water well
> > > > at all, they use ELF...
> > > >
> > > > Problem then becomes building a receiver or transmitter...
> > > >
> > > >
> > > > Ben, Wellington, New Zealand.
> > > > --
> > > >
> > > > http://www.lennard.net.nz/
> > > > Ben Lennard, NCEE, Dip EE
> > > >
> > > > Electronics R&D - Kiwi Made, Innovative Electronics.
> > > >
> > > > Hm: +64 4 972 7567
> > > > Mb: +64 21 536 627
> > > > 87 Spencer Street
> > > > Crofton Downs
> > > > Wellington
> > > > New Zealand
> > > >
> > > > "To the optimist, the glass is half full. To the pessimist,
the
> > > glass is
> > > > half empty. To the engineer, the glass is twice as big as it
> needs
> > > to be."
> > > >
> > > > No animals were harmed in the transmission of this email,
> although
> > > the
> > > > Dog next door is living on borrowed time, let me tell you!
> Those
> > > of you
> > > > with an overwhelming fear of the unknown will be gratified to
> learn
> > > that
> > > > there is no hidden message revealed by reading this warning
> > > backwards.
> > > >
> > > > > From: "codepro" <codepro@y...>
> > > > > Reply-To: basicstamps@y...
> > > > > Date: Tue, 26 Nov 2002 23:37:55 -0000
> > > > > To: basicstamps@y...
> > > > > Subject: [noparse][[/noparse]basicstamps] Re: Underwater communication
> > > > >
> > > > > I am also a amateur radio operator. Mike why did you
decide
> to go
> > > > > with 420mhz?
> > > > >
> > > > > MIT has developed a submarine called ORCA. It states the
> > > following
> > > > > in the journal paper that describes ORCA "The wireless data
> link
> > > is
> > > > > a pair of Freewave DGRO frequency-hopping spread spectrum
data
> > > > > transceivers. These devices operate over the 902-928 MHz
> frequency
> > > > > band, transmitting at 1 W. They connect to the host
computer
> using
> > > > > an RS-232 serial port and have a maximum data rate of 115
> > > kbps/sec.
> > > > > In air, they have a 20-mile line-of-sight range, but with
one
> unit
> > > > > underwater, depth becomes the limiting factor. In a
> chlorinated
> > > > > swimming pool, the units perform well up to a depth of
about
> 1 m.
> > > > > Communication with the vehicle can also be established
using a
> > > > > tether which provides an Ethernet link to the computer and
a
> live
> > > > > video feed from the CCD camera."
> > > > >
> > > > > Here is the link to the journal paper:
> > > > > http://www.auvsi.org/competitions/2002/papers/MIT.pdf
> > > > >
> > > > > --- In basicstamps@y..., Mike Blier <w6ffc@p...> wrote:
> > > > >> "It is interesting to see the range of opinions on this. I
> was
> > > > > also taught
> > > > >> that RF doesn't work underwater, but it
> > > > >> seems that it does anyway"
> > > > >>
> > > > >> I wasn't offering an opinion rather I was stating fact.
The
> R/C
> > > > > sub world
> > > > >> has been around for many, many years.(I have been involved
> for
> > > > > over 20) The
> > > > >> ranges we are talking about is quite short and the
> attentuation
> > > > > caused by
> > > > >> the radio receiver and antenna being in water is offset by
> the
> > > > > strength of
> > > > >> the signal from the controller.
> > > > >>
> > > > >> With standard R/C equipment only operating in the 200
> miliwatt
> > > > > range there
> > > > >> is still enough signal to penetrate the water for adequate
> > > control.
> > > > >>
> > > > >> I am also an amateur radio operator for over 43 years and
> have
> > > > > discovered
> > > > >> the RF doesn't always obey the standard conventions... I
> will
> > > > > have a
> > > > >> considerable investment in the current sub project and so
> > > > > to "hedge my bets"
> > > > >> I will be using 420 Mhz radios (in the 70 cm amateur band)
> that
> > > > > the Stamp II
> > > > >> will talk to on both ends. (Bidirectional communications)
> The
> > > > > data radios
> > > > >> have as an output the received signal strength. With the
> RSSI
> > > > > signal I will
> > > > >> use it to determine the power output necessary to maintain
> > > > > reliable comms
> > > > >> with the shore unit and adjust the transmitter(s) as
needed..
> > > > > These radios
> > > > >> are programmable under Stamp II control from 50 mw to a
full
> 5
> > > > > watts output,
> > > > >> that will get the job done for sure.
> > > > >>
> > > > >> I see you have posted the SubCommette web site link, they
> are a
> > > > > great
> > > > >> bunch and an excellent resource.
> > > > >>
> > > > >> R/C subs are a blast and I am sure the original poster
will
> get
> > > > > a great
> > > > >> deal of enjoyment from the hobby.
> > > > >>
> > > > >> Mike B.
> > > > >>
> > > > >>
> > > > >>
Original Message
> > > > >> From: "Michael Gianturco" <michcg@m...>
> > > > >> To: <basicstamps@y...>
> > > > >> Sent: Friday, May 24, 2002 8:23 AM
> > > > >> Subject: Re: [noparse][[/noparse]basicstamps] Underwater communication
> > > > >>
> > > > >>
> > > > >>> It is interesting to see the range of opinions on this. I
> was
> > > > > also taught
> > > > >> that RF doesn't work underwater, but it
> > > > >>> seems that it does anyway.
> > > > >>>
> > > > >>> Take a look at this site, dedicated to the very
substantial
> and
> > > > > popular
> > > > >> hobby of R/C submarines.
> > > > >>>
> > > > >>> www.subcommittee.com
> > > > >>>
> > > > >>> Maybe one of these guys could explain, in terms of
> wavelength,
> > > > > absorbance,
> > > > >> something physical -- why their
> > > > >>> machines remain under good control. I know it works fine
> but I
> > > > > don't
> > > > >> understand why. Michael
> > > > >>>
> > > > >>>
> > > > >>>
> > > > >>>
> > > > >>> Frank Stratton wrote:
> > > > >>>
> > > > >>>> I'm an amateur Radio Operator and RF underwater does not
> work
> > > > > very well.
> > > > >>>> The only RF frequencies that may work at all is the very
> low
> > > > > frequencies
> > > > >> at
> > > > >>>> 160 khz or less. These frequencies are used by
submarines
> to
> > > > > about 60
> > > > >> feet
> > > > >>>> below the surface.
> > > > >>>>
> > > > >>>> Frank
> > > > >>>>
> > > > >>>>>
Original Message
> > > > >>>>> From: Jason W. Day [noparse][[/noparse]mailto:j_w_day@y...]
> > > > >>>>> Sent: Wednesday, May 22, 2002 9:12 PM
> > > > >>>>> To: basicstamps@y...
> > > > >>>>> Subject: RE: [noparse][[/noparse]basicstamps] Underwater communication
> > > > >>>>>
> > > > >>>>>
> > > > >>>>> Anyone have an idea on how to send a wireless signal a
> > > > > distance
> > > > >>>>> of about 100
> > > > >>>>> feet underwater. Does RF work under water? I just want
to
> > > > > use a stamp
> > > > >> and
> > > > >>>>> send a signal to another stamp to turn on a light. Any
> ideas
> > > > >>>>> would be great.
> > > > >>>>>
> > > > >>>>> Thanks in advance,
> > > > >>>>>
> > > > >>>>> Jason
> > > > >>>>>
> > > > >>>>>
> > > > >>>>>
> > > > >>>>> To UNSUBSCRIBE, just send mail to:
> > > > >>>>> basicstamps-unsubscribe@y...
> > > > >>>>> from the same email address that you subscribed. Text
in
> the
> > > > >>>>> Subject and Body of the message will be ignored.
> > > > >>>>>
> > > > >>>>>
> > > > >>>>> Your use of Yahoo! Groups is subject to
> > > > >> http://docs.yahoo.com/info/terms/
> > > > >>>>>
> > > > >>>>>
> > > > >>>>
> > > > >>>> To UNSUBSCRIBE, just send mail to:
> > > > >>>> basicstamps-unsubscribe@y...
> > > > >>>> from the same email address that you subscribed. Text
in
> the
> > > > > Subject
> > > > >> and Body of the message will be ignored.
> > > > >>>>
> > > > >>>>
> > > > >>>> Your use of Yahoo! Groups is subject to
> > > > >> http://docs.yahoo.com/info/terms/
> > > > >>>
> > > > >>>
> > > > >>> To UNSUBSCRIBE, just send mail to:
> > > > >>> basicstamps-unsubscribe@y...
> > > > >>> from the same email address that you subscribed. Text in
> the
> > > > > Subject and
> > > > >> Body of the message will be ignored.
> > > > >>>
> > > > >>>
> > > > >>> Your use of Yahoo! Groups is subject to
> > > > > http://docs.yahoo.com/info/terms/
> > > > >>>
> > > > >>>
> > > > >
> > > > >
> > > > > To UNSUBSCRIBE, just send mail to:
> > > > > basicstamps-unsubscribe@y...
> > > > > from the same email address that you subscribed. Text in
the
> > > Subject and Body
> > > > > of the message will be ignored.
> > > > >
> > > > >
> > > > > Your use of Yahoo! Groups is subject to
> > > http://docs.yahoo.com/info/terms/
> > > > >
> > > > >
> > >
> > >
> > > To UNSUBSCRIBE, just send mail to:
> > > basicstamps-unsubscribe@y...
> > > from the same email address that you subscribed. Text in the
> Subject and
> > Body of the message will be ignored.
> > >
> > >
> > > Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
> > >
> > >
> > >
It is a loudspeaker mechanism with a metal plate attached instead of a paper
cone.
Speakers do work well underwater - I was present at the first underwater
marriage ceremony in the UK. Underwater speakers played "here comes the
bride etc"
Why don't you try the speaker thing for yourself in the bath(!)
Hook up a small loudspeaker to a battery radio and tune to your favorite
station, put it in a plastic bag and stick your head underwater. You'll soon
identify the best frequencies for underwater transmission!!
Tony
Original Message
From: "codepro" <codepro@y...>
To: <basicstamps@yahoogroups.com>
Sent: Thursday, November 28, 2002 3:10 AM
Subject: [noparse][[/noparse]basicstamps] Re: Underwater communication
> Tony, thanks for the info. The simple tone is a good idea, although
> I'm not sure how well a loundspeaker would work at sending and
> receiving sound underwater, if at all. To receive and send sound
> waves in the water a device called a hydrophone is used. The World
> War II Submarine operator's manual listed in a previous reply below
> describes the device. Also the follow link to the Association for
> Unmanned Vehicle Systems International (AUVSI) has journal papers
> that describes the use of a hydrophone for detecting ping signals:
> http://www.auvsi.org/competitions/2002/journal.cfm
>
> --- In basicstamps@y..., tony.wells@a... wrote:
> > Yes, there'se a lot of info around on google under "underwater
> digital
> > communications". Much of it refers to acoustic messaging.
> >
> > You might try some simple experiments with underwater low speed tone
> > transmissions between two loudspeaker in plastic bags for
> waterproofing - a
> > fun experiment at bathtime!
> >
> > Someone may already have experimented with free-air acoustic digital
> > transmission, so there may already be stuff around that you could
> adapt.
> >
> > For experimenting, you could use one loudspeaker as the sender,
> and the
> > other acting as a pickup.
> >
> > The sending side is relatively simple. The receive side will need a
> low
> > impedance audio amp and a system to turn a recognised tone into a
> 5V signal.
> > Do a search on google for circuits on the NE 567 PLL. For best
> results you
> > should use one tone for sending binary 0 and one tone for binary 1.
> So you
> > will need one low-impedance pre-amp and two tone converters.
> >
> > Getit working in free air to start with to prove it works (nice and
> noisy) ,
> > then underwater. Try it with one tone at a time at first, and try
> finding
> > two seperate frequencies well apart that work well.
> >
> > Regards,
> >
> > Tony
> >
> >
Original Message
> > From: "codepro" <codepro@y...>
> > To: <basicstamps@y...>
> > Sent: Wednesday, November 27, 2002 9:46 AM
> > Subject: [noparse][[/noparse]basicstamps] Re: Underwater communication
> >
> >
> > > Ben, thanks for that link, it's an interesting article. I've know
> > > about ELF for some time, but not those details. The article
> although
> > > does not mention the problems with sending sound through water.
> Here
> > > is a link to a World War II Submarine Sonar operator's manual that
> > > talks about what happens to sound when sent through water:
> > > http://www.maritime.org/fleetsub/sonar/chap3.htm#3A
> > >
> > > Here is a link to the full manual:
> > > http://www.maritime.org/fleetsub/sonar/index.htm
> > >
> > > There are a number of underwater acoustic modems on the market,
> > > listed below is a link to one that can supposedly do 28k baud
> with a
> > > maximum range of 6 km. Unless you own a oil platform you probably
> > > won't be able to afford it.
> > > http://www.bmt-wismar.de/bmteng/modem_en.html
> > >
> > > Here is link to a college paper that talks about what's needed to
> > > build a underwater acoustic modem:
> > > http://guinness.cs.stevens-tech.edu/~mtalreja/seniord/
> > >
> > > If anyone is serious about building one, let me know. I can help
> out
> > > in programming, but my knowledge of EE is limited.
> > >
> > > --- In basicstamps@y..., Ben <ben@l...> wrote:
> > > > For underwater comms, Military Subs use ELF. ie - from 30Hz to
> > > 300Hz (that
> > > > isn't a typo).
> http://www.oldradio.com/archives/jurassic/ELF.doc
> > > >
> > > > Basically because higher frequency radio will not travel through
> > > water well
> > > > at all, they use ELF...
> > > >
> > > > Problem then becomes building a receiver or transmitter...
> > > >
> > > >
> > > > Ben, Wellington, New Zealand.
> > > > --
> > > >
> > > > http://www.lennard.net.nz/
> > > > Ben Lennard, NCEE, Dip EE
> > > >
> > > > Electronics R&D - Kiwi Made, Innovative Electronics.
> > > >
> > > > Hm: +64 4 972 7567
> > > > Mb: +64 21 536 627
> > > > 87 Spencer Street
> > > > Crofton Downs
> > > > Wellington
> > > > New Zealand
> > > >
> > > > "To the optimist, the glass is half full. To the pessimist, the
> > > glass is
> > > > half empty. To the engineer, the glass is twice as big as it
> needs
> > > to be."
> > > >
> > > > No animals were harmed in the transmission of this email,
> although
> > > the
> > > > Dog next door is living on borrowed time, let me tell you!
> Those
> > > of you
> > > > with an overwhelming fear of the unknown will be gratified to
> learn
> > > that
> > > > there is no hidden message revealed by reading this warning
> > > backwards.
> > > >
> > > > > From: "codepro" <codepro@y...>
> > > > > Reply-To: basicstamps@y...
> > > > > Date: Tue, 26 Nov 2002 23:37:55 -0000
> > > > > To: basicstamps@y...
> > > > > Subject: [noparse][[/noparse]basicstamps] Re: Underwater communication
> > > > >
> > > > > I am also a amateur radio operator. Mike why did you decide
> to go
> > > > > with 420mhz?
> > > > >
> > > > > MIT has developed a submarine called ORCA. It states the
> > > following
> > > > > in the journal paper that describes ORCA "The wireless data
> link
> > > is
> > > > > a pair of Freewave DGRO frequency-hopping spread spectrum data
> > > > > transceivers. These devices operate over the 902-928 MHz
> frequency
> > > > > band, transmitting at 1 W. They connect to the host computer
> using
> > > > > an RS-232 serial port and have a maximum data rate of 115
> > > kbps/sec.
> > > > > In air, they have a 20-mile line-of-sight range, but with one
> unit
> > > > > underwater, depth becomes the limiting factor. In a
> chlorinated
> > > > > swimming pool, the units perform well up to a depth of about
> 1 m.
> > > > > Communication with the vehicle can also be established using a
> > > > > tether which provides an Ethernet link to the computer and a
> live
> > > > > video feed from the CCD camera."
> > > > >
> > > > > Here is the link to the journal paper:
> > > > > http://www.auvsi.org/competitions/2002/papers/MIT.pdf
> > > > >
> > > > > --- In basicstamps@y..., Mike Blier <w6ffc@p...> wrote:
> > > > >> "It is interesting to see the range of opinions on this. I
> was
> > > > > also taught
> > > > >> that RF doesn't work underwater, but it
> > > > >> seems that it does anyway"
> > > > >>
> > > > >> I wasn't offering an opinion rather I was stating fact. The
> R/C
> > > > > sub world
> > > > >> has been around for many, many years.(I have been involved
> for
> > > > > over 20) The
> > > > >> ranges we are talking about is quite short and the
> attentuation
> > > > > caused by
> > > > >> the radio receiver and antenna being in water is offset by
> the
> > > > > strength of
> > > > >> the signal from the controller.
> > > > >>
> > > > >> With standard R/C equipment only operating in the 200
> miliwatt
> > > > > range there
> > > > >> is still enough signal to penetrate the water for adequate
> > > control.
> > > > >>
> > > > >> I am also an amateur radio operator for over 43 years and
> have
> > > > > discovered
> > > > >> the RF doesn't always obey the standard conventions... I
> will
> > > > > have a
> > > > >> considerable investment in the current sub project and so
> > > > > to "hedge my bets"
> > > > >> I will be using 420 Mhz radios (in the 70 cm amateur band)
> that
> > > > > the Stamp II
> > > > >> will talk to on both ends. (Bidirectional communications)
> The
> > > > > data radios
> > > > >> have as an output the received signal strength. With the
> RSSI
> > > > > signal I will
> > > > >> use it to determine the power output necessary to maintain
> > > > > reliable comms
> > > > >> with the shore unit and adjust the transmitter(s) as needed..
> > > > > These radios
> > > > >> are programmable under Stamp II control from 50 mw to a full
> 5
> > > > > watts output,
> > > > >> that will get the job done for sure.
> > > > >>
> > > > >> I see you have posted the SubCommette web site link, they
> are a
> > > > > great
> > > > >> bunch and an excellent resource.
> > > > >>
> > > > >> R/C subs are a blast and I am sure the original poster will
> get
> > > > > a great
> > > > >> deal of enjoyment from the hobby.
> > > > >>
> > > > >> Mike B.
> > > > >>
> > > > >>
> > > > >>
Original Message
> > > > >> From: "Michael Gianturco" <michcg@m...>
> > > > >> To: <basicstamps@y...>
> > > > >> Sent: Friday, May 24, 2002 8:23 AM
> > > > >> Subject: Re: [noparse][[/noparse]basicstamps] Underwater communication
> > > > >>
> > > > >>
> > > > >>> It is interesting to see the range of opinions on this. I
> was
> > > > > also taught
> > > > >> that RF doesn't work underwater, but it
> > > > >>> seems that it does anyway.
> > > > >>>
> > > > >>> Take a look at this site, dedicated to the very substantial
> and
> > > > > popular
> > > > >> hobby of R/C submarines.
> > > > >>>
> > > > >>> www.subcommittee.com
> > > > >>>
> > > > >>> Maybe one of these guys could explain, in terms of
> wavelength,
> > > > > absorbance,
> > > > >> something physical -- why their
> > > > >>> machines remain under good control. I know it works fine
> but I
> > > > > don't
> > > > >> understand why. Michael
> > > > >>>
> > > > >>>
> > > > >>>
> > > > >>>
> > > > >>> Frank Stratton wrote:
> > > > >>>
> > > > >>>> I'm an amateur Radio Operator and RF underwater does not
> work
> > > > > very well.
> > > > >>>> The only RF frequencies that may work at all is the very
> low
> > > > > frequencies
> > > > >> at
> > > > >>>> 160 khz or less. These frequencies are used by submarines
> to
> > > > > about 60
> > > > >> feet
> > > > >>>> below the surface.
> > > > >>>>
> > > > >>>> Frank
> > > > >>>>
> > > > >>>>>
Original Message
> > > > >>>>> From: Jason W. Day [noparse][[/noparse]mailto:j_w_day@y...]
> > > > >>>>> Sent: Wednesday, May 22, 2002 9:12 PM
> > > > >>>>> To: basicstamps@y...
> > > > >>>>> Subject: RE: [noparse][[/noparse]basicstamps] Underwater communication
> > > > >>>>>
> > > > >>>>>
> > > > >>>>> Anyone have an idea on how to send a wireless signal a
> > > > > distance
> > > > >>>>> of about 100
> > > > >>>>> feet underwater. Does RF work under water? I just want to
> > > > > use a stamp
> > > > >> and
> > > > >>>>> send a signal to another stamp to turn on a light. Any
> ideas
> > > > >>>>> would be great.
> > > > >>>>>
> > > > >>>>> Thanks in advance,
> > > > >>>>>
> > > > >>>>> Jason
> > > > >>>>>
> > > > >>>>>
> > > > >>>>>
> > > > >>>>> To UNSUBSCRIBE, just send mail to:
> > > > >>>>> basicstamps-unsubscribe@y...
> > > > >>>>> from the same email address that you subscribed. Text in
> the
> > > > >>>>> Subject and Body of the message will be ignored.
> > > > >>>>>
> > > > >>>>>
> > > > >>>>> Your use of Yahoo! Groups is subject to
> > > > >> http://docs.yahoo.com/info/terms/
> > > > >>>>>
> > > > >>>>>
> > > > >>>>
> > > > >>>> To UNSUBSCRIBE, just send mail to:
> > > > >>>> basicstamps-unsubscribe@y...
> > > > >>>> from the same email address that you subscribed. Text in
> the
> > > > > Subject
> > > > >> and Body of the message will be ignored.
> > > > >>>>
> > > > >>>>
> > > > >>>> Your use of Yahoo! Groups is subject to
> > > > >> http://docs.yahoo.com/info/terms/
> > > > >>>
> > > > >>>
> > > > >>> To UNSUBSCRIBE, just send mail to:
> > > > >>> basicstamps-unsubscribe@y...
> > > > >>> from the same email address that you subscribed. Text in
> the
> > > > > Subject and
> > > > >> Body of the message will be ignored.
> > > > >>>
> > > > >>>
> > > > >>> Your use of Yahoo! Groups is subject to
> > > > > http://docs.yahoo.com/info/terms/
> > > > >>>
> > > > >>>
> > > > >
> > > > >
> > > > > To UNSUBSCRIBE, just send mail to:
> > > > > basicstamps-unsubscribe@y...
> > > > > from the same email address that you subscribed. Text in the
> > > Subject and Body
> > > > > of the message will be ignored.
> > > > >
> > > > >
> > > > > Your use of Yahoo! Groups is subject to
> > > http://docs.yahoo.com/info/terms/
> > > > >
> > > > >
> > >
> > >
> > > To UNSUBSCRIBE, just send mail to:
> > > basicstamps-unsubscribe@y...
> > > from the same email address that you subscribed. Text in the
> Subject and
> > Body of the message will be ignored.
> > >
> > >
> > > Your use of Yahoo! Groups is subject to
> http://docs.yahoo.com/info/terms/
> > >
> > >
> > >
>
>
> To UNSUBSCRIBE, just send mail to:
> basicstamps-unsubscribe@yahoogroups.com
> from the same email address that you subscribed. Text in the Subject and
Body of the message will be ignored.
>
>
> Your use of Yahoo! Groups is subject to http://docs.yahoo.com/info/terms/
>
>
>