<html><head></head><body><p dir="ltr">Floating is a good idea, but if you're towing a buoy anyway, that could be used to keep a neutral or negatively buoyant umbilical under tension and out of the way. In any case, you need to remain concerned about the power lost to dragging that umbilical through the water - it is not insignificant. I would want to avoid increasing its drag if you find you have an appropriate amount of power available currently.</p>
<p dir="ltr">There are two ways to tackle the problem: acoustic transmission (ultrasonic modem) or electrical / optical data transmission through a dedicated umbilical. The former has the advantage of independence, but if you're towing a buoy anyway, perhaps you could add transmission to your current setup without drastically increasing drag. Your budget will have an effect here. If I were to go all out I'd look at designing a buoy with integrated GPS, radio antennas, cell or what have you, and multiplex all of those signals down an armoured optical fiber to the sub. Your requirements are probably more modest... Perhaps you could simply add a watchdog / deadman conductor to your existing cable, such that a break in the circuit prompts some action on the buoy?</p>
<p dir="ltr">Sean<br>
</p>
<br><br><div class="gmail_quote">On May 5, 2015 5:11:42 PM MDT, hank pronk via Personal_Submersibles <personal_submersibles@psubs.org> wrote:<blockquote class="gmail_quote" style="margin: 0pt 0pt 0pt 0.8ex; border-left: 1px solid rgb(204, 204, 204); padding-left: 1ex;">
<pre class="k9mail"><br />Sean,<br />I am using a 1/4 inch nylon rope and it is quite buoyant. A coax would not be buoyant or is it? The line should be as buoyant as the rope to help avoid entanglement, mind you I have it rigged to be jettisoning.<br />Hank<hr /><br />On Tue, 5/5/15, Sean T. Stevenson via Personal_Submersibles <personal_submersibles@psubs.org> wrote:<br /><br /> Subject: Re: [PSUBS-MAILIST] cell phone link<br /> To: "Personal Submersibles General Discussion" <personal_submersibles@psubs.org><br /> Received: Tuesday, May 5, 2015, 7:06 PM<br /> <br /> Hank, if that's the case you could run a<br /> dedicated data cable to your buoy, or even run a cell<br /> booster with coax up to the buoy. What diameter is the<br /> line you're currently using? Another option is optical<br /> fiber, but then you have additional hardware cost on both<br /> ends.<br /> Sean<br /> <br /> <br /> On May 5, 2015 4:57:02 PM<br /> MDT, hank pronk via Personal_Submersibles<br
/> <personal_submersibles@psubs.org> wrote:<br /> <br /> Hi<br /> Lasse,<br /> Thank you for the link. <br /> Unfortunately they recommend a cable no longer than 50m. <br /> Most of my dive time will be between 400 and 500 feet. The<br /> cable would work fine because I tow a float the same way<br /> with buoyant nylon rope. I could bypass the acoustic radio<br /> altogether. <br /> Hank<br /> On Tue, 5/5/15, Lasse Schmidt via<br /> Personal_Submersibles<br /> <personal_submersibles@psubs.org> wrote:<br /> <br /> Subject: Re: [PSUBS-MAILIST]<br /> cell phone link<br /> To: "Personal<br /> Submersibles General Discussion"<br /> <personal_submersibles@psubs.org><br /> <br /> Received: Tuesday, May 5, 2015, 6:44 PM<br /> <br /> I don't know if this<br /> is<br /> of any help, but this unit allows for GSM calls<br /> underwater. I use their hydrophone in my sub<br /> and it works<br /> great.<br /> <br /> <a
href="http://www.oceanreefgroup.com/products/comms/products_alphauwcp.html">http://www.oceanreefgroup.com/products/comms/products_alphauwcp.html</a><br /> <br /> Cheers L!<br /> asse<br /> <br /> Lasse Schmidt<br /> Upplevelseakuten AB<br /> <br /> Skeppsbron<br /> 21, Tullhus 1<br /> <br /> 11130 Stockholm<br /> Telefon växel: 08-660 16<br /> 10<br /> Mobiltelefon: 070-28 32 660<br /> <br /> 5<br /> maj 2015 kl. 23:38 skrev hank pronk via<br /> Personal_Submersibles<br /> <personal_submersibles@psubs.org>:<br /> <br /> Hi all,<br /> I am curious if anyone knows a way that I<br /> can activate a cell phone from my<br /> submarine through my<br /> acoustic radio. I<br /> would have my acoustic radio mounted on<br /> my<br /> float (safety buoy) Since I dive alone I always tow a<br /> safety buoy with a diver flag. It would add<br /> a level of<br /> safety if I could call for help<br /> through my cell or a<br /> satellite radio.<br /> Hank <br />
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