Hi Tobie,

You might want to try contacting ARGOS  <http://www.argosinc.com/>. This is
a LEO satellite system that we use to track drifting buoys. You only need
about 1 watt or so to get up to the satellite and since the frequency is
401.65 MHz, the antenna can be made fairly small. The maximum amount of data
you can send is 32 bytes per message and you can usually send about 7 - 10
messages per satellite pass.

The transmitters usually start at about $500 USD. A couple of manufacturers
are Seimac <http://www.seimac.com> and Telonics <http://www.telonics.com>.

If you need more information, you can email me directly at makig@gate.net.

Hope this helps!

Greg Maki


-----Original Message-----
From: Tobie Horswill <thorswil@EXMACHINA.QC.CA>
To: PICLIST@MITVMA.MIT.EDU <PICLIST@MITVMA.MIT.EDU>
Date: Thursday, October 19, 2000 11:26 AM
Subject: [OT]: Long range position feedback anyone ?


>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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