Wednesday, 7 November 2018

LED Security Light - no RFI!

In the past, so-called security lights were incandescent units with bulbs that typically blew up after a few months.  Due to the cost of the whole lamp being close to the cost of the bulb, most people would not bother replacing the light, leaving it to rust on the side of the house.

But now, we have LED lights!  These offer about the same light of a 250W incandescent unit in a package that is small, lightweight and typically only uses 10W.


Of course, as someone involved with astronomy, I would very much encourage you to fit a PIR-operated unit, and ensure it is pointed downwards, where it won't uselessly light up the sky, disturb neighbours, and cause glare that diminishes, not aids visibility.


For us hams, LED lights are yet another potential source of RFI, often from unfiltered mains connections that allow the switch mode PSUs in these lights to inject interference directly into our wiring. 
No detectable RFI!

I bought a new LED unit earlier this week, for a demonstration of light pollution at the Snowdonia National Park headquarters.  It cost me just £8.   Even better, it produces no discernible RFI on any of the ham bands.  All the others I've tested have been so incredibly RFI-noisy that I put them in the bin immediately.

If you want one of these in the UK, you can find them here.  Elsewhere, you can probably find the same thing from the product reference number on the box pictured above, as they are mass-market things likely sold under a plethora different names.

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