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    Re: Dependence on GPS
    From: Tom Sult
    Date: 2009 Nov 01, 15:01 -0600
    Great point. I have several apps that can give me the alt and azm of stars at a given location. 

    Thomas A. Sult, MD
    Sent from iPhone

    On Nov 1, 2009, at 12:41, P H <pmh099---.com> wrote:

    Tom, I do not know the answer to your "jamming" question, but I am quite certain that non-GPS functionality of the smartphones would be unaffected.  That includes using your smartphone as a computer capable of celestial navigation computations, with Excel for instance.


    Peter Hakel
    http://www.navigation-spreadsheets.com/


    From: Tom Sult <tsult---.com>
    To: "navlist@fer3.com" <navlist@fer3.com>
    Sent: Sun, November 1, 2009 7:28:39 AM
    Subject: [NavList 10367] Re: Dependence on GPS


    I was in Europe earlier this year and for what ever reason my iPhone 
    would not get a GPS lock. I got a message that I may not have an 
    adaquite view of the sky. At the time I was on the summit of one of 
    the tallest mountains in Slovenia. Seems like I should have had at 
    least a reasonable view of the sky. I don't remember any large UFO's 
    overhead.

    I wonder if everyone's cell phones seaching for a cell could have been 
    enough to "jam" the signal. Or maybe I spilled some jam on it.

    Thomas A. Sult, MD
    Sent from iPhone

    On Nov 1, 2009, at 8:56, Fred Hebard <mbiew---.net> wrote:

    >
    > I would expect GPS units in a wrist-watch or arm-band configuration
    > would be less prone to "injury" while kayaking than deck-mounted
    > units.  A cell phone or two with GPS should be sufficient electronic
    > equipment for most sea kayakers, I would think.
    >
    > Fred
    >
    > On Oct 31, 2009, at 9:15 AM, Apache Runner wrote:
    >
    >>
    >>
    >> Frank makes a good  point about unnecessarily exposing oneself to
    >> risk and thereby endangering possible searcher-and-rescuers.
    >> There is this notion of risk homeostasis.  Mountain climbers are
    >> often accused of this.  It goes something like this:  "I got away
    >> with X last time, therefore I can get away with it next time."
    >> And then, they get nailed by putting themselves in some precarious
    >> situation.  The flip side of the coin is someone who analyzes a
    >> past outing for errors and corrects them.  I'm keenly aware of the
    >> issues of putting SAR'ers in jeopardy.
    >>
    >> I was in close proximity to a sea kayaking tragedy.  On Columbus
    >> Day weekend, 2003 (or 2004, I forget), I was kayaking in the fog
    >> off of Cape Cod.  The cheapy compass I was using got jammed with
    >> sea water, but I did have the good sense to wear a wetsuit - the
    >> water temperature was 55 degrees F.  Two girls went out in sea
    >> kayaks at exactly the same time as I was out, and they were maybe a
    >> half mile from me.  I used the wind and waves as a natural compass
    >> and hand-railed my way along the coast to get back home.  They got
    >> lost in the fog, and there was a two day search and rescue.  Two
    >> days later, they found the body of one of the girls.  The other
    >> was never found.
    >>
    >> By next spring, I had a brand new kayak and when I was paddling, I
    >> was about as tricked out as you could imagine.  Three compasses, a
    >> nautical chart, a VHF transceiver, a GPS unit, flare gun, combat
    >> knife (the kind SEALs use), you name it.
    >>
    >> Over time, I got more experience and learned that it actually is
    >> important to unclutter the deck of the kayak - having lost a lot of
    >> gear to waves, and also the junk gets in the way of rescues.    As
    >> mentioned, I experienced two GPS failures in conditions where I
    >> could've used them the most.
    >>
    >> My main kit now consists of a deck mounted compass, a hiker's
    >> compass in my PFD, a chart if in unfamiliar waters, a flare gun and
    >> flares, water, back-up food and protable VHF transceiver.  For
    >> longer trips, there's the usual camping gear, and I probably throw
    >> a GPS in a dry bag, but mainly as an afterthought.  In the fog,
    >> I'll bring a portable fog-horn.
    >>
    >> I've participated in six or seven rescues over the past five years,
    >> including 3 cases of helping motor-boaters who were lost in the fog
    >> and even had GPS'es.  Of course, they also had a few cases of beer.
    >>
    >> The main gripe about GPS'es for me is in the vein of the Charlie
    >> Brown comic story about Lucy and the Football.  Lucy convinces
    >> Charlie Brown, against all experience, to once again charge and try
    >> to kick the football, and she yanks it away as usual.  Last year,
    >> I found myself again shelling out $200 for a spiffy GPS unit.  Now
    >> my third -  thinking to myself "you're throwing away money...".
    >>
    >> This fall I'd given my students an exercise to walk from the chapel
    >> of the college to a tall building about a mile away and try to
    >> estimate the height of the steeple using the distance walked and
    >> the angular height.  I wanted to check the accuracy of my dead
    >> reckoning and brought out the $200 GPS unit to the college yard,
    >> and lo-and-behold - no signal.    Lucy pulled the football away 
    >> again.
    >>
    >> There is a definite sympathy to the issue of exposing would be
    >> rescuers to unnecessary danger by taking imprudent risks, but my
    >> own experience is that the GPS receivers end up being costly
    >> unneeded baggage.  This is not a Luddite statement, I will
    >> certainly carry a VHF any time I'm out on a kayak, but my
    >> experience is that these tend to be more reliable and a much more
    >> valuable piece of equipment than a GPS unit in terms of safety.
    >>
    >>
    >>
    >>>
    >
    >
    > >





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