For: Crossville Housing Authority

Date of Completion: May 24, 2006

Project Goal: To provide internet access to computer in a remote part of a two building complex.

Narrative: When I was first approached to do this project I had just completed the Tansi Pro-shop, Maintenance, and Snack bar Wifi project. The Tansi project required aerial mounted antennas, poll boxes, and several Access Points. So when I first looked at the HAFH project I was thinking large scale. After playing around with the ideal of externally mounted antennas and 100′ coax runs I took a step back and decided to approach this from a more simplistic standpoint.

The facility had an existing 802.11b network worked by an old Linksys AP, which sat nearly under a counter/desk. The problem was that the signal from this older Linksys AP would not reach down into the lower building annex where the computer they wanted to network was located. Even with elevating the AP to the top of the desk we could not generate enough signal. The distance was about 250 feet, but transited 2 or 4 external walls of brick, and many internal walls of typical governmental construction. Signal could be had just inside of the closest wall of the annex building to the main building.

I decided to use a two AP approach to this problem, and create a small mesh network, using WDS. This would have the advantage of being able to easily install more computers in the annex building should the organization require it. It would also not require coax runs, and cat v runs from the nearest inner wall to the computer in which was in the rear of the annex.

I selected my new standard of the Linksys WRT54GL as the model of AP. I have recently moved to the WRT54GL from the WRT54G after ver 5 of the later made it impossible to install Linux based firmware. Of course the stock firmware on the WRT54GL does not support WDS, so I loaded both units up with openwrt, RC5, from www.openwrt.org.

Setup of the WDS did take some time. Of course the united need separate IP addresses, and the MAC address of each other in their respective wl_wds nvram values. It was strange, but the network did not come alive right at way. It seemed to take 5 to 7 minutes for the units to linkup, but once they did it worked flawlessly. The named the unit “Base” and “Remote” with IP address of 192.168.1.1 and 192.168.1.2 respectively. I also disable all firewalling and DHCP server services on “Remote” because those function are now handled by “Base”.

To maximize the signal I decided on elevated mounts for both AP. The “Base” unit also required two cat V cables going to it in addition to power. One line for the DSL connection, the other line for connection to a small 10/100 switch which would service some existing hard wired computers. I opted for the small switch in order to keep wires running up the wall to a minimum.

I have to say I was pleased with the mounting, the “Base” unit mounted nicely on a wall out of direct line of site from the door. The “Remote” unit I hid behind a banner is a on of the day care classrooms which was equidistant between “Base” and the computer we wanted to service. The only thing required to run to the “Remote” unit was power, which came from a convenient outlet just under the mounting point.

The last peace of the puzzle came from the system we wanted to service. I used a simple Linksys USB client card for wireless connectively, and to insure good single, it too was mounted on the wall.

I fired up all the APs and give them time to link up, then installed the USB client card. The target system found its network, attached, and pulled an IP address from DHCP on the first try. Because I had replaced the older Linksys 802.11b AP, I had to go around and link each of the existing computers to the new SSID. I used two ssid, HAFH1 (from the “Base” unit) and HAFH2 (from the “Remote” unit), I had read that it’s a good ideal to name them the same, but I felt this would create some confusion, given the close proximity of the units.

In the end all the systems gladly linked to the new ssid, and I discovered an added bonus, that because of building fade issues, some of the preexisting computer had greater signal strength to HAFH2 than that of HAFH1, so placing these other computer of HAFH2 only further validated the additional AP.

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.