long range laser communication

[bissa]

I've gotten a school project where we need to redesign a network. part of this is connecting a satellite site that currently has no access to internet in any way. but it does have the environment to allow laser communication. the issue I'm running into is that I can't find any laser communication systems that are capable of reaching the 35KM distance that it would need to cover.
does anyone know about this kind of long range laser communication? or if this isn't a possibility, maybe another option.
as part of the project, we are doing this as a government project so cost isn't supposed to be an issue as long as we can justify it.

[Galcobar]

The environment being near-vacuum? Atmospheric issues -- basically, water or dirt -- are unfortunately quite effective at blocking laser transmissions. I recall Penn State working on a project to enable the military to communicate multiple GB/s across seven or eight miles with lasers, with digital signal processing to deal with all the distortions created by deflections of the laser beam in 2006, not sure what's become of it since.

[supaflyx3]

Although its not a laser, and doesn't have a reach of 35KM, but could possibly be modified to have a range like that, check out RONJA. RONJA - Wikipedia, the free encyclopedia

[sswilson]

Is the project outcome suposed to be a full time link, or a one-time stable connection to do upgrades, etc......?

If it's only one time stable, what about a multi tiered approach to different platforms at progressively higher altitudes, or if it's a full time link, maybe there needs to be an intermediary between the sattelite and the earth?

[bissa]

not a satellite, a satellite site, which is a location with very few people.
by "it has the environment" I mean that there is nothing obstructing the line of sight to the main site where this would be set up.
I have taken a look at RONJA, but it doesn't seem to be capable of anywhere near the range I need for this.
the purpose of the connection is to send data back on a fairly constant basis. so it does not need to be very fast, but preferably it would be usable. I might be able to suggest multiple repeaters every 5km or so, but I still would prefer something that needs a little in between as possible.
and I am aware that having laser connections at ground level is fairly painful, and that's probably why finding such a device to traverse 35km would be bad.
EDIT: and the reason I'm looking at this is that because of geographical problems, we can't run a wire out, and the site has no other conventional means of getting a connection.

[sswilson]

Originally Posted by bissa

not a satellite, a satellite site, which is a location with very few people.
by "it has the environment" I mean that there is nothing obstructing the line of sight to the main site where this would be set up.
I have taken a look at RONJA, but it doesn't seem to be capable of anywhere near the range I need for this.
the purpose of the connection is to send data back on a fairly constant basis. so it does not need to be very fast, but preferably it would be usable. I might be able to suggest multiple repeaters every 5km or so, but I still would prefer something that needs a little in between as possible.
and I am aware that having laser connections at ground level is fairly painful, and that's probably why finding such a device to traverse 35km would be bad.
EDIT: and the reason I'm looking at this is that because of geographical problems, we can't run a wire out, and the site has no other conventional means of getting a connection.

heh... sorry, not reading properly. :)

[bissa]

so I found this
highest capacity 5 ghz bridge - LigoPTP 5-N MiMo | Ligowave
it's not laser, but it covers the range I need and is good speed too. anyone have any experience with radio PTP connections?

[NyteOwl]

I think you'll find that in the long run a small microwave link, or even UHF will be cheaper, and more reliable than laser.

[Galcobar]

Hmph, Canada's microwave network is a pretty good example of creating communications links to small/unpopulated points.

[snoosebum]

If it doesnt need to be very fast whats wrong with a just a plain old radio and modem, 35 kms is easy for radio. We collect weather station data this way all summer, with very few problems.