I have one CFL at the moment which gives the same pattern on 24kHz. Over the years I have had all makes play up, one decided to wipe out 10MHz, that was due to a dry joint on a suppression capacitor. Dry joints have also caused other interference and total failure. I  have dismantled several CFL's, poor soldered joints are rife in them, some components can often be pulled dry from the PCB.
 Some designs are a nice source of a VLF ring core, material / type unknown, I have used them for coupling on two 500kHz / 136kHz multi turn RX Loops.

As for filament lamps, there is always the classic 'candle bulb effect' which wipes out  analogue TV, I did have the pleasure of finding one of those in a customers house once.

Eddie G3ZJO

On 01/03/2011 19:13, Mike Dennison wrote:

Today I noticed QRM on 136kHz that started when my wife switched a 
light on in our spare room. It had a low energy bulb by Status, and 
was marked "11W, 220-240V, 50/60Hz, 100mA". It is described on their 
web site as "stick type" and is bayonet fitting. The QRM consisted of 
rapidly changing noise sweeping back and forth across the band (see 
attached pic).

I replaced it with a Philips Genie WW287 light which did not seem to 
generate any noise.

The other low energy lights in the house are General Electric E27-ES 
11W bulb types which are very slow to get to full brightness, but are 
low QRM at LF. The rest are ancient filament types which are 
completely QRM-free of course.

So if you have this noise, perhaps it's one of your light bulbs.

Mike, G3XDV
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