wireless application

Have a relative with a cottage on a campground that recently put in free wifi for its members. But of course in her cottage she can't pick up the signal inside. Outside on the porch, she might grab signal at 20% or less, and hops around a lot. So I have been assigned with the task of "fixing her problem".

Here is the info I gathered doing a site survey...
First of all, I do not administer the local signal being put out, so I have no specific details or control over it.
Looks like they have an outside panel antenna mounted to a tower next to the main office. That's where the source is originating from. Her cottage is about 600 - 700 feet or so away from the originating antenna. Also through reasonable tree coverage, and over a small hill. I used a laptop with a usb wireless adapter and an active usb extension mounted to a pole. Walked around trying various spots and heights with Cirond WinC software to measure strength. What I found was at a certain location towards the rear of the cottage and about 10ft up, I would pick up signal at about 50% (I could never get more than that due to the distance I am guessing). By looking at the signal path visually, this was going through multiple trees, and one old building made of wood. by going up a minimum of 10ft, I was clearing the small hill. I am guessing they must be pumping out some decent power to be picking up 50% signal strength at a distance of 600ft or so and the trees & building.

So here is the plan I have come up with...
On the cottage, install a outside yagi antenna (+13.9 db) at 10ft up, run LMR-400 cable (15ft) into the cabin, connect to a linksys AP (WAP56G) in bridge mode, connect that to a WRT54G and broad cast to cover her cottage (on a different channel).
I am estimating I should be getting about 26 db of signal out.

I have set up several wireless systems, but not much to do with rebroadcasting applications. If I was picking up 50% signal strength with my little usb adapter, would that be enough to run the setup I am proposing?
And to connect back at that distance? That should be about twice the power my usb adapter has.

I am interested in hearing feedback from anyone who might have experience or thoughts in a setup like this. Is this overkill, or do I need to use an additional amplifier? I want to make a good educated guess on what I need before I start buying stuff to just try.

And no I don't think I can go high enough to clear the trees and buildings to get LOS. That would take a full blown tower.

Thanks All !

I have a long distance (2.1Km) connection on a section of my network that is just as you describe. I have overkilled it by putting a 24db grid array at each end and pumping out 84mw each end (WAP54G with firmware hack) This gives us ping times of 1-5ms at full speed. But this is point to point with both APs setup in AP mode. Our longest connection is 8.9km LOS. 24db Grid array at the router end with a 14db panel at the repeater end. Both ends are putting out only 22mw.

VERY BIG WARNING: putting out 84mw into 24db gives roughly 19 watts ERP(Effective Radiated Power). This is a LOT of power at that frequency and is NOT reccomended. This connection is rural so I am getting away with it.

I would suggest something like a 2.4GHz 14dBi Rootenna (RT24-14) as this allows the AP to be mounted at the antenna to reduce signal loss. You can also use POE to the AP.

You also need to consider whether you are getting a direct signal from the originating antenna because if you are only getting a bounced signal this could change with the seasons or surronding environment.

This site has a calulator so you can work out your power/antenna requirements with/without obstructions.

Radiolabs - Wifi Range Calculator

I hope my comments help in some way.

Regards

Fred