Re: GPS locator question

"-hh" <{rm_to_reply}hummer@xxxxxxxxxxx> wrote in message
news:ErIni.3949$I76.688@xxxxxxxxxxx
Joe Granto <joe.granto@xxxxxxxxxx> wrote:

WHAT I WANT: I transponder/receiver pair such that I can mount the
transponder in my dive flag styrofoam and have the receiver display
heading and distance to the flag. For example, my dive flag has the
transponder, and my wife has the receiver in the boat, and merely by
looking at the receiver she will know where I am.


In other words, you want a GPS that transmits its location, and a way to
receive that location signal, right?


Such a product exists.


It is currently used in commercial shipping and essentially works by
sending the GPS data through Marine VHF Radio, where other
similarly-equipped systems can receive the data.


It is called the Automatic Identification System (AIS)

See:
http://www.navcen.uscg.gov/enav/ais/default.htm


I would prefer it not be a kit, but rather an
out-of-the-box solution.

Class A systems are an "out-of-the-box" solution, but you'll probably
not like the price tag, plus I don't think that you'll meet all of the
carriage requirements to be legally allowed to use one, see

Title 33 CFR, 164.46 - Automatic Identification System (AIS).

There's a Class B system that's apparently been approved, but devices
are not yet available as per the US Coast Guard's website, above.


FYI, there's also a similar system that exists for aviation. A coworker
who has a small C172 owns & uses one, but I'm not sure how it does its
data dissemination: I think that this system might rely on Air Traffic
Control to be the data retransmission relay agent?


Briefly looking through some webpages to try to find system costs, it
looks like it would cost around $500 to add AIS **receive-only**
capability to a boat's existing Radio & GPS system. This would infer
that the AIS transmit side is significantly more expensive.


-hh

Normally I curse the mobile coverage here in PNG but on the weekend I was
able to get 2 bars while Madang town was just visible on the horizon. I'd
say we were at least 20 n miles from the tower. Cruising at 7 knots I was
making calls at 6:30PM and wasn't in harbour till 10PM. You may get a lot
less range depending on where the tower is. A PDA with wireless and a either
an internal or GPS or a Bluetooth unit would be good for your short distance
needs. As there is nothing blocking the signal you could get good range with
an external antenna on the boat. Kick in active sync, then the Active sync
remote display from the powertoys package and you should be set. getting a
pre WM5 device would be best as you can not active sync over wireless on a
WM5 and Bluetooth doesn't have as good a range. Bluetooth could work in a
pinch. Using Microsoft portrait would work as a walkie talkie too. Otter
cases are waterproof and allow use of the touch screen so you could be
writing a dive report for the newsgroup while waiting for pickup.
There are other packages but the one I described gives you a kit that all
devices involved have uses 7 days a week and no call costs. A Dell axim 30
is as cheap as chips and has the features needed with the extended battery.
The garmin mobile 10 if it is as sturdy as the GPS 10 would be a good match
for it. With that package you get turn by turn navigation for the car in the
bundle. For offshore Ozi explorer with some scanned maps would be a good
choice. With Ozi you can add maps for anywhere in the world with a little
research and can use tools such as Google earth to calibrate most maps
quickly and easily. The system isn't foolproof and shouldn't be used in life
or death situations but if the unit goes out of range at least your wife
should know where you were last reported at.

--
Brad Leyden
6° 43.5816' S 146° 59.3097' E WGS84
You haven't seen a stolen election yet, just wait for PNG in 2007.
Correction it won't be stolen, it will be purchased wholesale.
To mail spam is really hot but please reply to thread so all may benefit (or
laugh at my mistakes)




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