----- Original Message -----
From: Bob Ammerman <RAMMERMAN@PRODIGY.NET>
To: <PICLIST@MITVMA.MIT.EDU>
Sent: Thursday, October 19, 2000 4:22 PM
Subject: Re: [OT]: Long range position feedback anyone ?


> 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.

Oh, and since you know where the boat last was, and it probably hasn't gone
far since then:

A high directional, high gain, antenna on your receiver.

>
> 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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