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Frank, This has been a very interesting undertaking. The system I attempted to produce has many shortfalls and as I am nearing the end of the testing of this simple broadband systems capabilities I have come to fully realize this. The range is relatively short even in the best of conditions and ambient interference does reduce its range even further just when you would need it the most. On a submarine, the systems we rely on must work and work the first time...our very lives could depend on it. For someone who's desire is to delve into really deep water, this system might find a use for casual short range communications, but for emergencies or when longer ranges are required, a better system would be the way to go. At the time I delved into this idea, it seemed no one considered even listening to the sounds found in the water as important. Now, not only is listening of greater concern for safety, but sonar has entered to a point that underwater communications seem an essential tool not only in emergencies but to better aid us as we explore the largest unexplored area of the worlds surface. I have made many great friends along the way and could never have achieved nearly as much without this groups combined efforts. The system I have devised does remain a cheaper alternative to the many more capable systems now on the market and costs a fraction as much...but as the saying goes, you get what you pay for. Personally, if I were to delve into the real ocean, I'd want a real sonar communications system to get me home again. David Bartsch From: bottomgun@mindspring.com To: personal_submersibles@psubs.org Subject: RE: [PSUBS-MAILIST] retractable buoy Date: Thu, 29 Oct 2009 19:13:46 -0400 Frank, Hard wired systems have been used in the past by big subs since a large buoy is necessary to support the weight of the wire cable and telephone cable that attaches the buoy to the sub. Historical review of this system shows that if the buoy makes it to the surface and is found, it either doesn’t work or the cable is soon snapped due to a variety of reasons.
My suggestion for the best, economical solution would be to use a thin Spectra line to the surface (VERY strong, floats, and doesn’t lose strength when wet like other aramid fibers). The surface float would contain one of the larger 406 MHz EPIRBs with a built-in GPS and is activated when turned right-side up. Since you were a good mariner and registered your EPIRB, the Air Force’s Rescue and Coordination Center will receive your distress signal within a few minutes of the EPIRB being activated, isolate your location within a few hundred feet, and identify the distress alert as a submersible (from your registration). They will notify at least the Navy (as they are the primary rescue service for stranded submersibles) and maybe the Coast Guard. If you have chosen your UQC operational frequency carefully so that it will operate on one of the Navy’s frequencies used for submarine rescue, you will be able to communicate your situation. Only larger USCG vessels may have a UQC capability. A pinger on the hull will assist location efforts if the EPIRB buoy becomes separated from the sub (the Coast Guard has sophisticated programs to estimate drift for locating the original position of the buoy).
As I have explained before, basic oceanography and physics principals are against David’s design. While he has had some success under ideal conditions, either deeper water or saltwater will degrade the intelligibility of attempted communications. Anyone working with underwater sound (and especially a SONAR Tech.) will understand the SONAR equation that governs the transmission of sound underwater. Usually when a submarine disaster occurs, water conditions are not the best and if the sub is located, there will probably be more than one vessel operating in the area further complicating the acoustic spectrum in the range of the human ear. The ultrasonic single-sideband UQC communication units are designed not only for range but to communicate under adverse sea conditions. As I have said before, an MIT student in the late 70s built units similar to David’s units but of more robust components and with much more power (200 to 500 watts) and determined that this method was not feasible for consistent communications (let alone where your life may depend on the equipment). To test David’s com units properly and objectively, in water acoustic sound strength meters are necessary as well as a means to look at the frequency response out of the receiver. I do not denigrate the hard work, effort, and money that David has put into this effort…he has already been recognized for his extreme effort via a PSUB award but first principals should always be understood when entering an effort of this nature. While it appears very simple, in reality, it is rather complicated to have a successful product. As PSUBbers, we need to understand the limitations of a piece of equipment that appears to work but in time of dire need, it can not only let us down but may put our loved ones at risk if they are riding the sub with us. R/Jay
From: owner-personal_submersibles@psubs.org [mailto:owner-personal_submersibles@psubs.org] On Behalf Of ShellyDalg@aol.com
Hi Jon. Yes, no doubt David's system is inadequate to meet all the needs of the subbers in it's present form. Phil's system is obviously very good as witnessed by us all. My question (copied above) was how could a "hard wire" system be set up to communicate with a sub that is maybe stuck and was able to release a buoy to the surface. David's system will get some good testing next year as a means to talk between subs, most likely ones that are pretty close to each other, or to someone on the barge, again close by. I was wondering if a long wire could ( 1000 ft.? ) be placed in a pool and get a voice transmission through it. If ( and that's a big "if") it was possible to get a voice signal through on a relatively small wire, it could be used as an added safety device for emergencies. We've talked extensively on escaping from a sub and it never sounded like much fun. If a sub is very deep and divers can't get there, it would help if we could at least talk to the trapped guys and maybe figure out a way to get them up. If good "hard wire" and "real time" comms were on hand, it could be possible for the trapped guys to guide a hook within reach or maybe some other type of help. A wire system wouldn't be any good for just having a "chat" but in an emergency may be of some use. P.S. Send me an off-line note so I can ask you a question. Frank D. Windows 7: It helps you do more. Explore Windows 7. |