The truth about ferrites

These tests and experiments were performed by Ian Jackson VK3BUF in the QRM Guru test lab. Much has been said about the importance of applying ferrite clamps, rings and beads to radios and other domestic products to fight QRM. Articles on the correct placement of ferrite noise suppressors are common, but little has been written […]

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Anatomy of a Philips LED Light

So, what’s inside one of these lights that has the potential to create so much HF interference?   We opened up a common Philips 10W lamp with an angle grinder to see what makes it tick.   There are fourteen LEDs wired in series, with a likely working voltage of around 35V.  However, the actual voltage […]

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LED Lights – Test Results

Some of the most common RF noisy products around the house are LED downlights.  We have had reports of banks of LED lights (60+ lights) causing QRM for HF radio at distances of up to 400 metres.   Plenty of retailers sell LED lights of various brands, but it is almost impossible to tell if these […]

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Noisy fluorescent lights

Here is an example of fluorescent light RFI; thought to be RF quiet, but in reality far from amateur radio friendly.  Even though the observed noise on the radio was low, this is an example of “just another” noise source adding to the overall rise in the noise floor.     Key words: Fluro lights

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LED Lights – Recommendations from Hams

The following LED lights items have been reported as amateur radio friendly by VK Hams.  QRM.guru and the developers are unable to independently verify these products and have published these recommendations in good faith. During tests conducted in December 2019, the following products from five different manufacturers resulted in a clean bill of health. Other […]

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