Minimising Interference

Users of wireless LAN equipment over distance are increasingly affected by rising levels of interference due to the ubiquitous microwave wireless usage in the home and office, further fuelled by the low costs, easy setup and the potential benefits that the technology offers.

Also access to the radio band used is relatively unregulated, called the ‘public park’ concept there is minimum regulatory interventions to control use.

The use of a ‘public park’ concept approach is administratively efficient and gives great freedom to wireless LAN users, but the price of this freedom is increased interference. Clearly the very thing that has created an environment where communities can establish wide area networks like Air-Stream is the very same environment which has created an interference problem. Consequently, minimising the impact of interference through public awareness, and providing an open platform for wireless LAN 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 all Air-Stream access point advertise the SSID 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 may be pointed.

For example an Air-Stream access point will use the SSID: Air-Stream-Location-Name and a Backhaul 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 set-up complies to the ACMA regulations.

Nevertheless there are some other basic steps that can be deployed to minimise 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 Wireless or similar and ask others for their advice