Wireless Networking at Andrews University
12/2/99
Daniel Bidwell
Reg Swensen
Choice of Vendor
We started studying wireless in 1996.
We chose a 2MB product from Aironet in 1997.
We have since upgraded to an 802.11 11MB product.
They use Spread Sprectrum Technology.
Spread Spectrum
Multiple radio frequency channels each carry the same bit.
Each bit is decided by election.
This allows for low power transmissions to operate well below the threshold of noise.
Due to low power (100-200 milliwatts) you must hav eline of sight.
The 802.11 timing specifications are set for distances of up to 1 mile.
Configuration and Locations
We have a 12 db omni-directional antenna w/ bridge at the top of a 150' water tower. It is connected by coax to our campus fiber network in another building
Airpark bridge with a 14 db yagi about 1.2 miles from the water tower
23 db directional antenna w/ access point on a 50' tower at my house (5.2 miles from the water tower).
3 db omni-directional antenna w/ bridge at the Auto-Tech center about 1 mile from the water tower.
2 db rubber duck antenna sitting in a second story window at the Lake Union Building ½ miles from the water tower.
23 db directional antenna bridge on an 80' tower at Reg's house 5.3 miles from the water tower.
Steps to start up
Start with a topotraphical survey for line of sight.
Delorme TopoUSA version 2 for $49.00 works for short distances (5-7 miles).
Difficulties
The 2 db connection at the Lake Union Building experiences some loss of signal strength during heavy storms, but users don't seem to notice.
The coax between the base of our water tower and the campus fiber network gets fried just about every major thunderstorm that goes through. Extending the fiber network to the water tower will take care of this.
Current Plans
We currently have one 2MB wireless lan running in our Architecture bulding.
We are installing 11MB wireless in the library and other major classroom centers this month.
We plan toinstall wireless throughout the cmapus, inside and out.
We are considering our student apartments.
Repeaters and Amplifiers
We are running 5.3 miles from an omni directional to a directional disk.
With a directional to diretional and an amplifier we should be able to go as far as 60 miles without a repeater.
Work with an RF engineer if you want to use repeaters or amplifiers.
Interesting URL's
http://www.fcc.oet/info/rules/part15/part15-mar99.pdf Fcc rules for wireless power.
http://www.winncom.com Power amplifiers for spread spectrum equipment.
http://www.ydi.com vendor of radios and antennas for spread spectrum systems.
http://www.eposhow.com/wireless/whp.htm Comprehensive list of manufacturers of wireless equipment.