Minimising Interference
Users of wireless LAN equipment over distance are increasingly being effected by rising levels of interference due to the ubiquitous nature of wireless usage in the home and office, further fueled by the low costs, easy setup and the potential benefits that the technology offers.
Also access to the radio bands used by this equipment is relatively unconstrained, called the 'public park' concept the planning objective of regulative authorities is for all users to be able to access a small portion of the total resource and to share that resource in a way that requires minimal regulatory intervention provided the power is kept well down.
The use of a 'public park' approach is administratively efficient and gives great freedom to users, but the price of this freedom is increased risk of interference. What is often miss-understood by many users of wireless LAN equipment is that this framework equally applies to all users regardless if you are a telecommunications carrier or an individual.
Clearly the very thing that has created an environment where communities can establish wide area networks like Air-Stream is the same environment which has created the interference problem.
Consequently, minimising the impact of interference through public awareness, and providing an open platform for users to share information to maximise the effectiveness of their equipment and minimising interference is important to all.
Advertising your SSID
One of the ways to minimise interference is through advertising your SSID so that other users of the band can take steps to avoid interference and conflicts.
For this purpose Air-Stream advertise the SSID on all their AP’s including backhaul links between sites. This not only makes it easier for users to connect, but also provides other wireless users with all the information needed to minimise interference.
This information can be acquired easily via any wireless device when completing a site survey providing information about the user, channels used, general location and the direction in which antennas maybe pointed.
For example an Air-Stream AP will use the SSID: Air-Stream-Location Name and a Back Haul link may have an SSID: Air-Stream-LoacationFrom-LocationTo
Using your equipment correctly
The correct use of equipment is another way wireless users can minimise interference, this can be done by ensuring your setup complies to the ACMA regulations.
See: ACMA Requirements
Nevertheless there are some other basic steps that can be deployed to minimize interference and maximise connectivity between sites. This includes:
- Use the most appropriate antenna for the task
- Prefer antenna gain, receive sensitivity and good LOS over device transmit power
- Ensure good antenna alignment on directional antennas, always maximise the signal even if your signal is already good to reduce stray interference
- Use the correct coax cables and fittings to ensure equipment is appropriately shielded, earthed and protected from the elements
- If you build a home brew antenna, try finding someone who can test it for you. Poor SWR can reduce performance and increase interference for others
- Join a group like Air-Stream or similar and ask others for their advice