Low-RF Computer?
DesignGuy wrote:
I'm looking to replace the computer at my listening post, and would like to
find out if any certain brand of computer is known to have a low RF output.
I get a lot of noise on the SW bands from my existing PC (Micron) and leave
it off most of the time, which defeats the purpose.
What I'd like to do is replace with a low RF and acoustically quiet model,
and then get a flat-panel LCD screen and wireless keyboard and mouse. Any
problems with RF noise from wireless devices such as those?
Comments, experiences, etc. all welcomed.
Laptops are hard to beat for RFI issues.
You might want to take a portable SW like a DX398 and go to the local
stores
and check them out. I helped a friend find a low noise HP with my DX398
and
my RFI probe made from ~20 turns of #20 PVC insulated wire on a pill
bottle
form. I measured the inductance and found it to be ~20uH. I went to the
extra
trouble of putting a BNC and built several probes so I could have
different
probes for different RFI searches. I used ~3' of RG174 with a BNC on
one
end and a3.5MM on the other.
Be prepared for some odd looks and hesitation from the sales droids.
They must have thought we were AQ operatives or something.
A very usefull link for info on how to suppress most RFI can be found
at:
www.yccc.org/Articles/W1HIS/CommonModeChokesW1HIS2006Apr06.pdf
Ferrites will work near magic, but you have to use MANY more then
commonly
understood.
We, my wife and I, lucked out and we bought some NOS Gateway Solo
PIII 650MHz laptops with reasonably low RFI. Most of the PC RFI now
comes from the switch mode PS. Ferrite quitens it, but I built a couple
of very quite linear 120V to 18V DC supplies with very good filtering
to
keep the PC noise from reaching the AC mains. A bunch of ferrites on
the network and modem make it very acceptable.
Terry
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