Interesting.
Also a few problems. Without using a satelite you will probably have to use
HF frequencies. Even without the legal question, this is not going to be
too reliable unless you can find a quiet band to operate on. Additionally,
the lower the frequency, the larger your aerial will need to be for
efficient operation. I'd almost suggest  VLF if it didn't require very
large antenna systems.
An iridium cellphone system  (if it's still operational) might be a
solution - but costly.
Im intreged by this one & will watch for other comments closely.

Richard P



Hi,

    I know close to nothing regarding wireless transmission such as radio,
packet, satellite and  the like but I was wondering if there would be an
economic way for an autonomous vehicle to send it's position back home ?
The
vehicle is a solar powered boat already equipped with a GPS receiver used
for navigation and it would be a piece of cake to add a daily routine to
the
PIC for uploading this information to some RF stage. Here is the catch :
the
boat can be anywhere in the middle of the Atlantic ocean and obviously has
very little power available (in fact barely enough to keep it moving). The
boat could stop while it transmits to save power and wait for it's
batteries
to recharge before going on, that's not a problem. The required bandwidth
is
minimal and only a few bytes would be sent daily. The received data would
be
used to update the boat's daily position on a Web site. At this point, I'm
only looking for one-way transmission, nothing would get sent back to the
boat even though that would be cool ...

    I was thinking of something like the transmiters they put in Tuna fish
to track their migration habits. Any idea who makes these things and how
they work ? Is direct ground to ground transmission possible accross the
Atlantic with such little power available ? Is satellite the only way to go
?

Thanks,


Tobie Horswill
 Ex Machina, Quibec (Quibec) CAN
thorswil@hotmail.com

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