When setting up a TV antenna in Australia, most people focus on the direction, height, or signal type but often overlook one crucial factor: polarisation. Antenna polarisation refers to the orientation in which the signal is transmitted and received: either vertical or horizontal. Choosing the wrong polarisation can drastically reduce your signal strength and TV reception quality.
In this blog, we’ll explore what polarisation is, how it works in Australia, and how to determine whether you need a vertical or horizontal antenna alignment for your location.
1. What is Antenna Polarisation?
Polarisation is the orientation of the electric field in a radio wave. TV broadcast signals in Australia are transmitted either vertically or horizontally from transmission towers, depending on local infrastructure and geography.
Your antenna must match this polarisation to properly receive the signal. Otherwise, you risk signal degradation or complete signal loss.
2. Vertical vs Horizontal: What’s the Difference?
- Horizontal Polarisation:
- The antenna elements (rods) are aligned horizontally.
- Traditionally used for most metropolitan and high-power regional transmitters.
- Vertical Polarisation:
- The antenna elements are aligned vertically.
- More common in smaller towns, local repeater sites, and mobile transmission areas.
The correct polarisation maximises reception efficiency. An antenna aligned 90 degrees off from the transmission polarisation can lose more than 20 dB of signal—enough to disrupt even strong broadcasts.
3. How to Know Which Polarisation Your Area Uses
Use the following methods:
- mySwitch Tool: Visit myswitch.digitalready.gov.au, enter your address, and review the transmitter info—it will tell you the recommended antenna type and orientation.
- Observe Neighbours’ Antennas:
- If nearby antennas are mounted with horizontal rods, your area likely uses horizontal polarisation.
- If they are vertical (rods standing up), it’s vertical polarisation.
- Check Local Transmitter Info: Review the transmitter’s technical info (available from ACMA or your antenna installer) to confirm the polarisation mode.
4. Common Polarisation Setups Across Australia
- Metro Cities (Sydney, Melbourne, Brisbane, Perth):
- Use horizontal polarisation for main broadcast towers.
- Regional Areas:
- Mix of both, depending on distance and geography.
- Remote or Repeater Sites:
- Often vertical polarisation to reduce tower and infrastructure costs.
5. Choosing the Right Antenna Based on Polarisation
- Horizontal-Only Antennas:
- Suitable for major metro areas.
- Better gain and channel coverage for large networks.
- Vertical-Only Antennas:
- Used for fringe areas with vertical transmission.
- Multi-Polarised or Adjustable Antennas:
- Can be adjusted to either vertical or horizontal orientation.
- Ideal for households between two broadcast regions.
6. The Impact of Incorrect Polarisation
Installing an antenna with the wrong polarisation can result in:
- Weak signal strength
- Missing channels
- Inconsistent picture quality
- Frustration during channel scans
Correct alignment ensures that the maximum signal energy is captured, especially in regions with fringe reception.
7. Polarisation Tips for DIY Installers
- Use a spirit level to ensure accurate mounting angle.
- Double-check antenna documentation to confirm polarisation capabilities.
- Adjust in small increments and use your TV’s signal quality meter to measure results.
Polarisation plays a vital role in the performance of your TV antenna. Whether you’re upgrading your system or installing a new one, knowing whether to align your antenna vertically or horizontally can make all the difference.
Use tools like mySwitch, observe your neighbours’ setups, or contact a local expert to ensure you’re aligned with the right polarisation. And if you’re not sure where to start, Super Antenna is here to help with customised, polarisation-optimised antenna solutions across Australia.
