Just my few pennies worth:
If you need a QRM-free energy saving lamp, try a mains powered LED.
I have one here, with a pleasant *warm white* tone, which doesn't
cause QRM because it cannot:
There is only a full-wave rectifier in it, a small capacitor, a
current limiting resistor, and -hold your breath- :
About 80 (!) small white LEDs all connect in series, driven directly
from the rectified mains !
I removed the outer glass dome because imo the LEDs got a little hot
inside, but no problems with it ever since.
Starts immediately at full intensity, and by theory should not
suffer from frequently turning it on / off .
Downside: Quite expensive, almost 20 Euros for a single 4 Watt
lamp. Hope it lasts forever ;-)
Cheaper LED lamps were sold at "Aldi" (german food discounter) about
a year ago, only 2.5 Watt, 110 lumen, but also warm colour,
QRM-free, and now serving as 'ambient illumination' for the shack.
Another "huge" LED I tried was a low-voltage powered white "Monster
LED" by Huey Jann, but I didn't like the colour which is somehow
"purplish" :
http://www.hueyjann.com.tw/self_pages/en/hi_power_led_10w_100w.html
Cheers,
Wolf .
Am 01.03.2011 21:04, schrieb [email protected]:
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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