[Ham-Computers] RE: Computer noise in receiver

Tue, 23 Dec 2003 14:24:07 -0800

Just a comment about this.  An LCD flat panel may not solve all problems.
They also have a couple of gotchas.

The AC adapter is typically a switching power supply that's poorly shielded.
Many flat panels use a built-in power supply, so finding a "quieter"
external supply is not an option.  Also, the fluorescent backlighting on TFT
displays is also powered by a HV step-up switching power supply that may
cause RFI.

If you do get a LCD flat panel, best thing to do is to look for one that
uses an external supply.  That way, you can bypass the "wall wart" if it's
noisy.  Better yet, see if it takes 12v in...then you can power it off your
station's supply (and battery backup if power goes out)!  As for the HV
backlight supply...well, you'll just have to get a unit that doesn't
generate much RFI.  Luckily, most are pretty quiet.

And watch out for those "gotta have one" flat panel plasma displays...I've
never tested one, but I'm sure it would be RF noisy as heck!  Would you
expect otherwise from a system that uses HV arcing through a gas?  =)  Does
anyone have one and can comment?

73,

  - Aaron, NN6O

-----Original Message-----
From: Woody [mailto:[email protected]]
Sent: Tuesday, December 23, 2003 1:37 PM
To: [email protected]
Subject: Re: [Ham-Computers] Computer noise in receiver

Hi Jim:

The easiest way to solve your interference problem is to replace the CRT
monitor with an LCD flat panel monitor.  LCD monitors do not cause
interference like a CRT monitor.  

You can also try changing the vertical sync rate and the display resolution.
This will not eliminate all interference, but it will change the frequency
of the interference so that you may find a combination that you can live
with. 

Depending on the interference level, you may also reduce the interference by
placing a couple of large ferrite chokes or torroids on the video cable at
both the monitor and PC ends of the cable.

----- Original Message ----- 

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