Lake Tansi Wide Area Wifi
For: Lake Tansi
Date of Completion: May 1, 2006
Project Goal: To eliminate the need for multiple broadband Telco Internet Connections inside a multi-building complex
Narrative: While this was not my first wide area wifi project, it is one of the ones I am more pleased with. The concept was to blanket an area of Lake Tansi, which would encompass the golf pro shop, the “snack bar” and several maintenance buildings, with 802.11g network coverage which would allow Tansi to reduce it’s dependence on Telco Broadband Internet, and reduce it’s cost to a single connection. Fortunately, Tansi had recently installed a series of storm warning siren towers. These tall wooden polls with domes atop them provided the perfect place to get the all important “line of sight” required by 2.4 GHz distance transmissions.
Starting off, I planed to install a main Access Point which the other APs would connect to. We selected the warning tower behind the maintenance building just off the golf course. This site provided good coverage to the primary areas we wished to start serving, and had the added advantage of being located with the bounds of a restricted area fence line, thus adding additional site security. For the antenna, I opted for a 120 deg sector antenna, whose field of view gave the best concentration of signal for the area we wished to cover. To house the Linksys WRT54GL Access point and the cable modem, I used a weather tight housing mounted at the foot of the poll. Power for these units was pulled from the warning alarm box with which we where now co-located. Because of the height involved, I contracted with a local crane service to lift a man up the 70 feet to the top of the pole to mount the antenna. We then ran low-loss coax down the poll and into the weather box. This combination of antenna and low-loss coax allowed me to use this main tower with NO additional amplification of the 2.5 GHz signal beyond what is standard for the radios on the WRT56GL.
Perhaps the most amusing aspect of this project was dealing with Charter Communication’s (the local Cable Company). Of course dealing with any large organization it is almost impossible to get them to “think outside the box”. So we had to provide Charter with some creative instructions on where to drop their Cable Internet Line. I am quite sure that they are not used to dropping cable connections at polls well away from any buildings. Fortunately, the sub contractor who showed up to do the job was flexible and seemed amused at our plan. He pulled in a line from a nearby poll and after an hour or so cable internet was established.
The “remote” units we intended to hang off of the main tower fell into two categories. True wifi clients, who will use a standard client card (albeit with some additional antennas), and additional Linksys WRT54GL configured to act as Mesh units with and without there own subnets. So the main tower WRT54GL had to be configured to be as open as possible. Of course the firmware standard on the WRT54GL was not up to this task, so I installed the OpenWRT linux based firmware.
“The Maintenance Buildings” The first computers I attached to the new tower were also the closest. I used standard Linksys USB client cards on Windows XP computers to attach these computers to the main tower, just as if the AP was sitting in the office down the hall, expect in this case the AP was 300+ feet away. One of these computers was located in the back of a metal building. This required a work around of using USB extension cables and powered hub to allow me to position the USB device up into the rafters of the building, thus circumventing the metal walls.
“The Pro Shop” The Pro Shop served as the base for the next jump off point. Here there was a small network of computers which used property software to manage their golf course. This network had to remain intact so as not to require mass reconfigure of property software. I opted to use a second WRT54GL (again with OpenWRT firmware installed) as a “Mesh” unit off the Main tower.
To maximize signal, I used a direction Yagi antenna off of the Pro Shop WRT65GL mounted onto a satellite dish to link back to the main tower. Low-loss Coax was again used to attach the antenna to the WRT54GL, and no amp was needed.
“The Snack Bar” Here as a bonus I decided to open up wifi access to the patrons of the restaurant. There is also a computer here which needed to link back to the Pro Shop for the golf management software. I used a Client Network on a separate subnet and opened up the access to all to use. I then used an existing wired connection for the Snack Bar computer to talk back to the Pro Shop, those protecting that link.
“The Light Poll” It became clear after a few weeks of use that a large oak tree would intermittently cut signal from the main tower to the Pro Shop despite the use of directional antennas. We opted to install a “banked shot” WRT54GL unit on the poll which housed the power and timing equipment for the Golf Cart Crossing Signal across Dunbar Road. This Unit would be in Meshed with the rest of the units in the complex. While the Main Poll/Pro Shop Link would continue to function, this Light Poll unit will fill in the gaps should rain or oak tree leave obscure the signal. The unit also has the added benefit of supplying better overall coverage to the parking lot and pavilion areas of the complex.
Conclusion: This is only a first phase of a larger wifi project underway. I am in talks with Lake Tansi to provide Wifi coverage for their rental units, Security building, POA office, and parts of the golf course. This system once fully realized with provide an area network which could support phone (via VoIP) and Security Camera Images in addition to Internet network data.
