No need to point the antenna: point the boat!

Radio is not my specialty, but...

Transmit on a known schedule.

Transmit highly redundant data.

Look at some of the techniques used to pull usable signals out of the noise
on deep space probes.

I would expect that a few watts would get you where you need to go.


Bob Ammerman
RAm Systems
(contract development of high performance, high function, low-level
software)

----- Original Message -----
From: M. Adam Davis <adavis@UBASICS.COM>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Thursday, October 19, 2000 4:04 PM
Subject: Re: [OT]: Long range position feedback anyone ?


> 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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"[BUY]:","[AD]:" =Ads
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>
>

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