Wireless Equipment Essentials
Never power on wireless equipment without antennas connected. Powering on radio equipment without an antenna connected can cause permanent damage of the radio transmitter.
Always use Coax Seal Tape. Many wireless installers forget about this vital part of their installations and end up with expensive repairs a few months later. It is very important to seal all outside connector joints to prevent moisture from entering. It is best to use a self bonding type tape as these tend to give the best seal.
Keep Coax Cable runs to a minimum. When ordering Coax Pigtails and extension cables to connect your access point to an antenna, keep the cables as short as possible for best performance. Use CA-400 for long cable runs as it has a lower loss of around 0.22dB per meter at 2.5GHz. We use Times Microwave LMR195 for shorter cables under 2 meters and this has a loss of around 0.6dB per meter at 2.5GHz. Remember to take the loss of RF connectors and coax cable into account when designing your wireless network.
Getting the most out of your Wireless Network
If you are having problems with your wireless signal there are some things to check for first:
Look for non Wi-Fi related Interference
Look for other 2.4 GHz equipment nearby like cordless phones, Bluetooth devices, microwave ovens etc. Your neighbours may also have a wireless access point on the same channel as yours. There are plenty of wireless scanning tools available (Free and Paid) for Mac (inSSIDer), Windows (inSSIDer, Acrylic Wi-Fi), and Android (WiFi Analyzer) operating systems.
Evaluate the building structure
The make-up of the building will also affect the signal, things such as metal studs in walls, concrete, concrete fibreboard walls, aluminium cladding, and foil-backed insulation in the walls or under the cladding, pipes, electrical wiring and furniture.
Other common things that can block 2.4GHz signals are tinted windows, wire mesh with holes smaller than a quarter wavelength (about 2.5cm), and wire mesh with holes up to 12.5cm. It is also a good idea to keep your access point as high as possible and away from metal objects and concrete walls as these can block and/or reflect the signal causing signal degradation.
Here are some common building materials with their average attenuation:
Plasterboard wall: 3dB
Glass wall with metal frame: 6dB
Block wall: 4dB
Office window: 3dB
Metal door: 6dB
Metal door in brick wall: 12.4dB
MetaGeek also has an excellent Training and Education section on their website to help with WiFi design and troubleshooting.
Radio Frequency Line of Sight (RF LOS)
Radio frequency LOS is very important when designing point to point links, as RF LOS is not the same as visual LOS. The Fresnel Zone is an important part of the RF link because it defines an area around the LOS that can introduce RF signal interference if blocked. Objects in the Fresnel Zone such as trees, hilltops, and buildings can diffract, reflect or absorb signal away from the receiver, changing the RF LOS. These objects can cause degradation or complete signal loss. To have a viable RF link 60% of the Fresnel Zone must be free of obstructions. The Fresnel Zone is at its widest in the middle of the link.
Most large wireless manufacturers provide Link Calculation tools for their equipment that can assist with the link planning process. These link calculation tools can give you an idea of whether your link will be obstructed and what equipment you need to give you the best signal and performance. One common misconception is that using a high gain directional antenna can "blast" through trees, buildings and other objects - this almost never works. A directional antenna that can transmit 30km in free space won't even go 1km if the path is obstructed.
Note: It is important when using antennas for longer distance communications that you have similar strength radios and similar gain antennas at each end. If you don't you run the risk of being able to receive signal, but not transmit back for two way communication. Your link will only be as good as the weakest end. It is no good putting a 15dbi omni on your roof and trying to use a laptop to communicate to it 2km away, as you will be able to receive a signal from it, but the laptop will not be able to transmit enough signal back.
Good Signal can't be Guaranteed
Even when all the above precautions are taken into account, no one can guarantee a good link, as there are many more factors that could cause problems. Go Wireless NZ sells equipment in good faith and can only accept returns due to faulty equipment as per the warranty.