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Al, No one wants to admit being ignorant about anything, but when it comes to underwater SSB communications, I can only admit this to be an area to which I have not been exposed. The truth is that if you could take your intended message and alter it so that noise of about the same frequency that you would consider undesirable or "extra" could be filtered out, this would be a better way to go. Farther ranges in higher seas and in more crowded boat congestion would be a great bonus with such a system. The seeming lack of enthusiasm should not be taken in a wrong way. I for one (and many silent psub members) would love to make use of such a system, but would feel at the mercy of present manufacturers such as Alec is now. An understandable home built system or at least someone within this club who could be turned to in my times of trouble would be a great help. I would be very interested in such a system and encourage you to complete a working prototype for evaluation and review. I would love to comb over schematics or a basic block diagram of this to get a better idea of how this is performed. (we never stop learning) If work in this area were easy, we all would be doing it. Keep up the great work in this area! David Bartsch > Date: Tue, 19 May 2009 20:31:45 +0000 > From: wreckdiver@frontiernet.net > To: personal_submersibles@psubs.org > Subject: RE: [PSUBS-MAILIST] system completetion > > Alec, > > No such luck with the marine VHF...underwater SSB comm is done at ultrasonic frequencies...on the order of 20-30Khz. A marine VHF (which is Frequency Modulated as opposed to Single Side Band) operates at a frequency in the neighborhood of 156 Mhz. Way too high a frequency...the water would absorb all the RF energy within a couple of feet. We do know that sound travels well underwater though. While David's system will work in relatively quiet conditions, if you get in a crowded lake or river with a lot of motor boat traffic or general U/W noise, it will be a different story. Probably more like trying to whisper to someone across a crowded room at a party. That's where ultrasonic comm is a better choice (albeit more expensive). You are still working with sound but it is outside the audible range so you can filter out all the audible noise, demodulate the signal, and have clear audio. Now it's far from perfect....it is still line of sight (get behind a shipwreck and no comm) and is affected by thermalclines, etc. > > I have a design for a VLF SSB transceiver that could be constructed for less than the comercial (OTS, etc) units, although I haven't done a detailed price estimate yet. The biggest hurdle is finding a reasonably priced, commercially available transducer to use (which is why I enquired about your Divelink transducers). Commercial ones are in the $100's or even $1000's of dollar range and the only affordable ones are replacement ones for OTS and others who appear reluctant to sell them separately unless you can prove you already own one of their units. > > I can publish the schematic for those interested and possibly even get some PC boards made up (after redesigning the output stage to drive a transducer instead of an antenna) but the last time I offered or inquired, nobody seemed interested. It all hinges on finding an affordable transducer that I can get electrical specs on. > > Al > > ----- Original Message ----- > From: Alec Smyth <Alec.Smyth@compuware.com> > To: personal submersibles <personal_submersibles@psubs.org> > Sent: Tue, 19 May 2009 14:04:19 +0000 (UTC) > Subject: RE: [PSUBS-MAILIST] system completetion > > Thanks David, I'm really interested but will wait to see what Divelink > come back with before making a final decision. It's fantastic you're > doing this, I appreciate it. While a single sideband unit from OTS is > probably the ultimate, I really like something that we can build > ourselves and 350' sounds like sufficient for most PSUBS operations. > > Basic question... I have a marine VHF sitting on a shelf. Is it possible > to leverage that so that underwater it would transmit/receive through a > hydrophone instead of the antenna? Sorry if this is a completely > ignorant question, but it's just provoked by the fact it already has a > handset, speaker, and amplifier. I'm envisioning the addition of a > switch between surfaced mode (antenna) and submerged (hydrophone), but > imagine it couldn't be that simple. This is something I really know > nothing about. > > > thanks, > > Alec > > ________________________________ > > From: owner-personal_submersibles@psubs.org > [mailto:owner-personal_submersibles@psubs.org] On Behalf Of David > Bartsch > Sent: Tuesday, May 19, 2009 02:06 > To: personal_submersibles@psubs.org > Subject: RE: [PSUBS-MAILIST] system completetion > > > Alec, > > Dean just received his console #4 and has placed a request for yet > another unit. Seems he wants one for his support craft as well. > Les already has two units and posted some test results from earlier > this year. He cut holes in the ice on a nearby pond and was able to > cross talk some 350' apart. > The system I have developed is a basic communications system that uses > an underwater speaker and the listening device is our HBH-2 hydrophones. > Two boats simply talk back and forth. There is no carrier so as ambient > noises rise, the range will diminish. > I looked into "underwater speakers" and actually bought one only to > find the maximum operating depth was but 14'. (This would have been real > useful to us) I have discovered that by installing a sound device for > solids into a metal dish and pouring two part molding plastic, you can > make an underwater speaker capable of going down quite deep. (exactly > how deep is yet to be established) This special transmitter is not > expensive and can be seen under special projects under my name and "UW > COMMS". > The cost for a complete system including two passive hydrophones and > this voice transmitter is $245.00 and in most instances, this includes > shipping. > A cb styled handset automatically shifts the unit from receive to > transmit and back again once the message is sent. > The basic block diagram is on the last picture under UW COMMS and I > will aid anyone who wishes to make a unit of like construction on their > own. The preamplifiers and amplifier cards are kits from various > suppliers that anyone with a little time and patience can put together. > The battery is self supplied and is 12 vdc. (this negates the need to > ship lead) > The goal was to make available a simple to use underwater > communications set that will allow two submarines to talk to each other > while both are up to 500' down and 500' apart. Talking from sub to > support vessel without surfacing would also be nice. > Dean has yet to try out his latest toy, but from those that have > ventured into the world of underwater sound with these things, I have no > complaints. > At present, console #1 is with Frank D. in California, #2 and #3 are > with Les Katschor in Michigan, #4 and soon #5 will be with Dean Ackman, > and more will follow. > These are easy to build, repair and maintain and should make submarine > activity safer as these consoles allow for the listening of ambient > noise such as boat traffic. > The newest attempt at a sonar system is essentially only a single > amplification channel for listening only. This should be great for > collision avoidance. > If you think you would enjoy a simpler form of communications with > in-club support, just give me the word. > > > David Bartsch > > > > > > ________________________________ > > Subject: RE: [PSUBS-MAILIST] system completetion > Date: Mon, 18 May 2009 13:34:08 -0400 > From: Alec.Smyth@compuware.com > To: personal_submersibles@psubs.org > > > Hi David, > > I'm getting my sub ready for the summer and one repair item was the > Divelink comms. One of the units failed and I just posted it to the > manufacturer who will test and provide an estimate for repair. They may > come back with some silly number. So I was wondering what the latest is > on your version? Did Dean get to test this? > > > thanks, > > Alec > > > The contents of this e-mail are intended for the named addressee only. > It contains information that may be confidential. Unless you are the > named addressee or an authorized designee, you may not copy or use it, > or disclose it to anyone else. If you received it in error please notify > us immediately and then destroy it. > > > From: owner-personal_submersibles@psubs.org > [mailto:owner-personal_submersibles@psubs.org] On Behalf Of David > Bartsch > Sent: Sunday, May 10, 2009 02:17 > To: personal_submersibles@psubs.org > Subject: [PSUBS-MAILIST] system completetion > > > Dean, > > Your passive sonar/underwater communications console #4 is completed > and has passed all of the initial in-lab performance testing. > This electronic enclosure along with its two passive hydrophones > (HBH-2) and single broadband voice transmitter will be shipped out to > you on Monday, May 11th via U.S. Postal Priority mail. A simplified set > of laminated operating instructions will also be provided. > I am pleased with this systems performance as I am sure you will be > also...good luck with your submarines launch and call should you have > any questions. > > > David Bartsch > > > ________________________________ > > Hotmail(r) has ever-growing storage! Don't worry about storage limits. > Check it out. > <http://windowslive.com/Tutorial/Hotmail/Storage?ocid=TXT_TAGLM_WL_HM_Tu > torial_Storage1_052009> > > > ________________________________ > > Hotmail(r) has ever-growing storage! Don't worry about storage limits. > Check it out. > <http://windowslive.com/Tutorial/Hotmail/Storage?ocid=TXT_TAGLM_WL_HM_Tu > torial_Storage1_052009> > > -- > Al Secor > > > > ************************************************************************ > ************************************************************************ > ************************************************************************ > The personal submersibles mailing list complies with the US Federal > CAN-SPAM Act of 2003. 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