We are overrun with RF radiating consumer electronics. They have invaded every part of our domestic, commercial, manufacturing and automotive lives. Globalisation of product markets has had a marked negative impact on compliance standards and quality contol.
We are surrounded by so much of this equipment that it has become ubiquitous; to the extent we don’t even notice it. Much of it is imported and does not comply with Australian standards, and this is the underlying reason for so much of the noise that radio amateurs suffer; especially in built up suburban areas.
You can learn more about product compliance and labelling here
The compliance mark (or Tick) is shown to the left. It supercedes all previous ticks, images or labels that some manufacturers or equipment may use.
Most, not all, consumer equipment that has dirty RF compliance can radiate noise in the range from 2-3 metres up to 30-50 metres. Properly installed data cables will tend not to radiate more than 2-5 metres. However, and by contrast, non-compliant equipment can radiate via power cables up to 30-50 metres.
The table below provides some broad profiles of noise sources and possible mitigation strategies.
Where available, a sample noise file has been included for reference purposes.
|Switch Mode power supplies||These devices power many different types of consumer electrical devices. Generate square-waves in the range 20-120kHz. There will be harmonics and peaks spaced at multiples of the switching frequency. Noise will be broadband in nature.||15-30m||Replace with linear power supplies.
Replace with filtered supplies
Install clip-on ferrites & ferrite rings
|Fluorescent Lights||These will exhibit a broadband noise similar to switch mode power supplies.||30m +||Good grounding. Keep radio receivers as far away as possible.
Shield power leads.
Replace with quality LED light.
|Desk Lamps – power supplies||Similar to switch mode power supplies||15m +||Replace with a quality product – test first or ensure you can return|
|Battery chargers – both automotive, mobility and small USB style and walwart chargers||These will exhibit a broadband noise similar to switch mode power supplies. They may also have spikes across sections of the HF spectrum.||30m +||Install clip on ferrites or suppressors. Turn off the offending device when operating radio.|
|Plasma TVs||Noise peaks 60Hz apart with sharp peaks||30m +||Discard and buy a modern LED TV|
|Halogen downlights||Low voltage lights powered by switch mode power supplies which generate and radiate broadband noise||30m +||Replace with quality LED downlights, replace noisy power supplies with quiet ones or a wound transformer|
|Electric motors||As used in some appliances and may create a rhythmic noise that varies with motor speed||30m +||Install a filter or capacitor to suppress or pass the noise to ground.|
|Thermal contacts||For example an urn, fish tank thermostat, electric blanket, hot water service may result in a broadband buzzing style of noise. It may also present as pulsing between 1-5 seconds||50-300m||Install a filter or capacitor to suppress or pass the noise to ground. A snubber could be used.|
|Kitchen appliances||Mixers, grinders or coffee machines and similar are well known for broadband noise, wiping out large chunks of the spectrum||30m +||Replace, run via an approved filter or don’t use during amateur radio operations|
One VK3 ham happily recommneds the following LED light.