[RFI] Switching Supplies - Filtered connectors for video noise

Fri, 26 Oct 2001 12:26:40 -0400

If the monitor uses a switching supply, there is no such thing as turning it
off unless you unplug it.

Have found Tv's with switching supplies that put out more noise into my
shortwave listening and ham bands when 'turned off' than when it was turned
on. Had to unplug it to kill the noise.

That is why all my ham power supplies are transformer and not switching....
with the exception of the one in my FT-1000MP that is internal, well
filtered, and short leads. Not had a problem with it. But if I were to use
an external supply, it would not be a switching supply.

I have also found that the video card made a big difference with the rfi I
would get. The faster and jazzier the card, the more noise I got. Some of
sounds I got as rfi reminded me of jamming from the days of old on the
shortwave bands! Frequently these sounds change with the pattern of the
image on the screen. They frequently generate questions from swl about the
'new' digital mode that they are hearing on the band.... hi hi

73 from Bill - WD8ARZ

----- Original Message -----
From: "Cortland Richmond" <ka5s@earthlink.net>
To: "Pete Smith" <n4zr@contesting.com>
Cc: <rfi@contesting.com>
Sent: Friday, October 26, 2001 11:40 AM
Subject: Re: [RFI] Filtered connectors for video noise

> Video card, or monitor? Does tuning off just the monitor change things?
> Cortland
> Pete Smith wrote:
> > I have what's gotta be the noisiest video card in the world, in my
> > computer.  When it's on, I get severe broadband noise (no birdies here!)
> > an HF receiver not only in the room with the computer, but adjacent to
> > furnace thermostat, any electrical conductor, and out in the back yard.
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