Wfi over water

Hi,
Just wanted a little brainstorming on this one.
here's the scenario: There are two islands separated by a body of
sea(water). they are 22 miles apart. there are 8 ferries which ferry
people between these islands. at any given point of time only 4 ferries
are in the water ( 2 up and 2 down). What would be the best way to
provide seamless wifi connectivity to the people on the main passenger
deck of the ferries?.
and the above is not in the seattle region!!!
I personally was thinking of putting directional antenna on radios on
either island, and omni antennae on radios on the ferries to serve as
the backbone. now provide an ap on each of the ferries and voila!.
The things that could go wrong are: -
a) wireless propagation over sea (ive read that 5 Ghz OFDM provides as
much as 20 miles over water
http://www.fcw.com/geb/articles/2005...i-01-20-05.asp)
b) whether the boats will be able to maintain connectivity with each
other/island base station at all times
c) whether all of the above can be done dirt cheap!!!

outbackwifi wrote:
>> Hi,
>> Just wanted a little brainstorming on this one.
>> here's the scenario: There are two islands separated by a body of
>> sea(water). they are 22 miles apart. there are 8 ferries which ferry
>> people between these islands. at any given point of time only 4
>> ferries are in the water ( 2 up and 2 down). What would be the best
>> way to provide seamless wifi connectivity to the people on the main
>> passenger deck of the ferries?.
>> and the above is not in the seattle region!!!
>> I personally was thinking of putting directional antenna on radios on
>> either island, and omni antennae on radios on the ferries to serve as
>> the backbone. now provide an ap on each of the ferries and voila!.
>> The things that could go wrong are: -
>> a) wireless propagation over sea (ive read that 5 Ghz OFDM provides
>> as much as 20 miles over water
>> http://www.fcw.com/geb/articles/2005...i-01-20-05.asp)
>> b) whether the boats will be able to maintain connectivity with each
>> other/island base station at all times
>> c) whether all of the above can be done dirt cheap!!!
Doubtless there are many in the group who have a great deal of
experience in practicalities of this sort of problem. My 2p is this; the
distance to the horizon, assuming one ae is at sea level(I presume this
would not actually be so ) the other would have to be at 270' to
achieve LOS. You get my drift.(Touch of nautical humour...not) This page
may help with the calcs. http://www.boatsafe.com/tools/horizon.htm

--
In my sentences I go where no man has gone before...I am a boon to the
English language. -- George W. Bush

Interesting application.

I suspect that an omni directional antenna on the boat would not be good
enough. Assuming that you are looking for a good, not perfect link, you
could take advantage of the fact that while enroute the ferry is always more
or less aimed in the same direction. You could put a directional antenna at
each end of the ferry, aimed at each harbor. This could feed a bridging
access point, that could then connect to another Access Point that provides
service to the users on the ferry.

The question is whether you can find off the shelf equipment that can
automatically use the more powerful signal, and switch between the two.

Report back on how you make this work.

Mike Schumann

"outbackwifi" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed) oups.com...
> Hi,
> Just wanted a little brainstorming on this one.
> here's the scenario: There are two islands separated by a body of
> sea(water). they are 22 miles apart. there are 8 ferries which ferry
> people between these islands. at any given point of time only 4 ferries
> are in the water ( 2 up and 2 down). What would be the best way to
> provide seamless wifi connectivity to the people on the main passenger
> deck of the ferries?.
> and the above is not in the seattle region!!!
> I personally was thinking of putting directional antenna on radios on
> either island, and omni antennae on radios on the ferries to serve as
> the backbone. now provide an ap on each of the ferries and voila!.
> The things that could go wrong are: -
> a) wireless propagation over sea (ive read that 5 Ghz OFDM provides as
> much as 20 miles over water
> http://www.fcw.com/geb/articles/2005...i-01-20-05.asp)
> b) whether the boats will be able to maintain connectivity with each
> other/island base station at all times
> c) whether all of the above can be done dirt cheap!!!
>

On Mon, 07 Feb 2005 03:33:18 -0800, outbackwifi wrote:

> Hi,
> Just wanted a little brainstorming on this one. here's the scenario:
> There are two islands separated by a body of sea(water). they are 22
> miles apart. there are 8 ferries which ferry people between these
> islands. at any given point of time only 4 ferries are in the water ( 2
> up and 2 down). What would be the best way to provide seamless wifi
> connectivity to the people on the main passenger deck of the ferries?.

Check out your local tern/pelican/sea eagle communities. Perhaps you could
tag some of them with small light-weight solar powered wi-fi transponders.

You would be well and truly stuffed however, if they were migratory or
they stayed too close to shore, so it might not be seamless.

For seamless operation each boat requires satellite IP. You would
distribute the connection on each boat via a wi-fi access point.

If you can't afford the satellite connectivity but still need to advertise
that your boats have wi-fi, then you could set up each boat's hot-spot
splash page to display a message that says something to the effect of "The
MV WoodDuck's hot-spot is currently down for maintenance, we regret this
inconvience and hope to have it fixed as soon as possible".


Phuoc

"For seamless operation each boat requires satellite IP. You would "
Not realy
Actually, if i were to use mesh routers on each of the ferries, i'd
have a self-healing network. (UCW has an open-source mesh router OS).
This way the four ferries plus the two on either islands would always
form a wireless mesh (except probably on days when the no of boats goes
down)

We WiFi marinas. The task you have chosen, though doable, is not cheap.

Besides land-based high-power units and high-gain antennas you will need
approx 150' to may be 300' land based antenna towers(depending upon the
scenario finally selected) to clear the distance. This is still no guarantee
of good service. Additionally, you may need to create a corrosion proof
antenna system for the ferries.

Satellite IP is probably the way to go.

But again, the solution will not be cheap.


"outbackwifi" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed) oups.com...
: Hi,
: Just wanted a little brainstorming on this one.
: here's the scenario: There are two islands separated by a body of
: sea(water). they are 22 miles apart. there are 8 ferries which ferry
: people between these islands. at any given point of time only 4 ferries
: are in the water ( 2 up and 2 down). What would be the best way to
: provide seamless wifi connectivity to the people on the main passenger
: deck of the ferries?.
: and the above is not in the seattle region!!!
: I personally was thinking of putting directional antenna on radios on
: either island, and omni antennae on radios on the ferries to serve as
: the backbone. now provide an ap on each of the ferries and voila!.
: The things that could go wrong are: -
: a) wireless propagation over sea (ive read that 5 Ghz OFDM provides as
: much as 20 miles over water
: http://www.fcw.com/geb/articles/2005...i-01-20-05.asp)
: b) whether the boats will be able to maintain connectivity with each
: other/island base station at all times
: c) whether all of the above can be done dirt cheap!!!
:

On Mon, 07 Feb 2005 15:08:40 GMT, "Mike Schumann"
<mike-(E-Mail Removed)> wrote:

>Interesting application.
>
>I suspect that an omni directional antenna on the boat would not be good
>enough. Assuming that you are looking for a good, not perfect link, you
>could take advantage of the fact that while enroute the ferry is always more
>or less aimed in the same direction. You could put a directional antenna at
>each end of the ferry, aimed at each harbor. This could feed a bridging
>access point, that could then connect to another Access Point that provides
>service to the users on the ferry.
>
>The question is whether you can find off the shelf equipment that can
>automatically use the more powerful signal, and switch between the two.

MIMO routers, somewhat directional antenna which covers one 'wedge' for
each antenna port on the router.

Hi,

I've had much success with simple industrial grade outdoor wireless access
points. The product I used was a sputnik 3mile outdoor job..

There are several outdoor products that have much greater ranges now and
over open water is really the best scenerio for wireless applications.
Little interferance or terrain to block your signal.. I've been out 5 miles
off shore with a perfect signal.

--
802 Networks -- Think Wireless
http://forums.802networks.com


<(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> On Mon, 07 Feb 2005 15:08:40 GMT, "Mike Schumann"
> <mike-(E-Mail Removed)> wrote:
>
>>Interesting application.
>>
>>I suspect that an omni directional antenna on the boat would not be good
>>enough. Assuming that you are looking for a good, not perfect link, you
>>could take advantage of the fact that while enroute the ferry is always
>>more
>>or less aimed in the same direction. You could put a directional antenna
>>at
>>each end of the ferry, aimed at each harbor. This could feed a bridging
>>access point, that could then connect to another Access Point that
>>provides
>>service to the users on the ferry.
>>
>>The question is whether you can find off the shelf equipment that can
>>automatically use the more powerful signal, and switch between the two.
>
> MIMO routers, somewhat directional antenna which covers one 'wedge' for
> each antenna port on the router.
>