As this is quite an ambitious project, I would suggest two things:

Invite people from the ham groups to participate
Invite corporations to participate and donate

While this would involve your time and energy, your returns would be greater
than what you put into your efforts in these two areas.

In order to have a long distance transmission, you go as low in frequency as you
can (given antenna limitations), and you get as highly sensitive of a receiver
as you can.

If you want to increase project complexity, you can also get and use a compass
module to give you the direction you are currently pointing in.  Have an array
of antennas which are set up to cover 60 to 90 degrees, and use only one
antenna, pointing towards the USA, or the two antennas pointing east and west.
This would give you a longer distance transmission.

-Adam

Tobie Horswill wrote:
>
> 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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