[Elecraft] PC and video monitor QRM...

Sun Aug 24 15:17:00 2003

Hi Steve

You don't mention if the monitor is a CRT (cathode ray tube) or a modern
TFT-screen. Most of the PC QRM is caused by the CRT-monitor.
If it is a CRT, replace it by a TFT. It costs some money, but as a HAM you
will notice the drastic reduction in QRM.

73 Tom PA3DXV

----- Original Message ----- 
From: "Steve Banks" <[email protected]>
To: "Elecraft" <[email protected]>
Sent: Sunday, August 24, 2003 5:12 PM
Subject: [Elecraft] PC and video monitor QRM...

> Hi Everyone
>
> Does anyone have any suggestions about possible ways to reduce QRM
affecting
> a K2, which is likely coming from my nearby video monitor and/or PC, which
> are both AC-operated?
>
> Awhile back I think I read a post answering a similar question, which
> suggested installation of split beads of some type for the ends of the
PC's
> AC supply cord.  It may have also recommended similar treatment for the
> video card's signal line which connects to the monitor; however, the
details
> of the post escape my memory.
>
> In my case, the K2 and PC (and its monitor) are separated by about 3 to 4
> feet without extra shielding of any sort, except for the RF case covers on
> the PC.
>
> The QRM is worst on 20m.  (Naturally, that's where I sped a lot of time.)
> It's not terribly bad, but it definitely seems that the PC and/or monitor
> are the QRM source.  The interfering signal is a bothersome audible AC
hum.
> It tapers off significantly (essentially disappears) on the bands above
and
> below 20m with the PC and monitor turned on.  When the PC and monitor are
> turned off, the noise diminishes on all bands (especially 20m) by about
one
> S-unit compared to when they are both turned on.
>
> If anyone has suggestions, please feel free to write either via the
> reflector or directly to me.
>
> Tnx es 73,
>
> Steve Banks
> K0PQ
> K2 S/N 1599
>
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