Home Automation – Fun With The House Part 9

In between messing with the home automation, I dabble with ham radio as a licensed operator, my callsign is 2E0FWL, its a fun past-time.

I had not been on-air for a good while as i was busy with the decorating and stuff, I turned the radio on last week for play and to my horror was welcomed with 100% interference and very little else! The display on the radio looked like this…

Icom 7300 display

The display shows radio signals as a visible display, the yellow vertical bars are man-made interference. A normal view would be mostly black with some feint blue bars showing other stations transmitting. The blue ‘fog’ between the yellow is a mass of broad frequency noise.

This needed fixing clearly. The first thing to do is check if its outside as well – solar panels, phone masts, and other electrical gubbins can all do this damage, using a portable receiver, it was easy to test by tuning in to the noise then going outside – the noise stopped about 10 feet from the house – a clear sign it was coming from my house.

Next step is to turn things off – I killed the power to the light circuit and the noise went away, this shows it is coming from a light somewhere. Next we turn the power back on and start turning things off one by one – thing with ‘smart’ bulbs is that they are always on, they just do not light up when off 🙂

It turned out it was the power supplies used for the RGB LED strips in the living and dining rooms, turning these off fixed the problem. The supply modules i bought were slimline units as i wanted to hide them easily in the dropped islands. They look like this…

Very slim and tidy but oh so noisy. I bought some bigger units which look like this…

Looking at various circuit diagrams and inside the two styles of supply shows that the slim ones have an awful lot of components missing – mostly filtering and smoothing – hence the terrible noise emitted. The new ones have a lot more ‘guts’ in them and are completely silent in terms of radiated interference. My conclusion is that the first ones are total junk and in terms of certification alone should not be sold at all, chances are they have never even been tested/certified and were just more “Chinese junk” that we get so much of now.

The price for both types was almost identical as well !

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