Barry Oliver wrote:
>
> One application I have wondered about is RV campers. You know those
> people whose permanent address is a mailboxes etc. or an RV park. Plenty
> of RV's have satellite dishes, and have learned how to align them every
> night, I suppose it couldn't be any more difficult to do with an
> internet connection. But then I suppose the real purpose of living like
> that is to remain off the grid....
>
Depends on the particulars of the service. For 2-way data, you can
generally get aligned well enough to keep anyone from noticing. With
most setups, though, they are selling bandwidth on two different
polarizations (usually horizontal/vertical). This requires
"cross-polarization" be performed to minimize your potential
interference with the other pole that contains other paying customers.
(Like I said, though, this usually can be done yourself without anyone
noticing). The other issue with this is that your modem must know it's
coordinates in order to synchronize its transmissions. (The precise
amount of delay varies depending on your position on the earth -- which
directly correlates with your distance from the satellite)
There's also circular (vs. linear) polarization, which doesn't require
this step by nature -- but naturally, the transponder space is more
expensive.
They do, however, make auto-pointing antennas that can be had in the
sub-30K range if you find the right source. (For DirecTV, they've got
virtually flat antennas that will auto-point while you're driving for
only a couple grand). These point and polarize themselves because they
contain a GPS controller unit that is capable of calculating your exact
pointing angle and polarization angle based on the position of the sat
and your position on the earth. We've got them on a couple of demo
vehicles, and have sold them to a number of clients. They work pretty
darn well.
-Bill
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