"Caveat Lector" ) writes:
Used to be two ratings for computers -- one was a low radiation type
Can't find it on Google

People have already mentioned the class A and class B ratings, which I
think you are referring to. I have no idea if it's still in place, or
people are working from memory.

My memory says the stuff rated for business was less stringent, and if
that's a proper memory, I always thought it was because at home one is
surrounded by consumer devices like radios and tv sets, and the likelihood
of interference to those devices is high, hence higher standards.

Michael

Also Laptops offer a means of good shielding and several are low noise

And if you search the web - you can find several tips as how to quiet down
your computer

Try URL:
http://www.ac6v.com/comprfi.htm

CL

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

Equipment used in commercial settings is considered Class "A". Class "B"
digital devices are those intended for use in the home. FCC limits for RF
radiation differ depending on the application of the digital device. The
test distances for RF radiation are approximately three times closer for
Class "B" than Class "A".

"Michael Black" wrote in message
...
"Caveat Lector" ) writes:
Used to be two ratings for computers -- one was a low radiation type
Can't find it on Google

People have already mentioned the class A and class B ratings, which I
think you are referring to. I have no idea if it's still in place, or
people are working from memory.

My memory says the stuff rated for business was less stringent, and if
that's a proper memory, I always thought it was because at home one is
surrounded by consumer devices like radios and tv sets, and the likelihood
of interference to those devices is high, hence higher standards.

Michael

Also Laptops offer a means of good shielding and several are low noise

And if you search the web - you can find several tips as how to quiet
down
your computer

Try URL:
http://www.ac6v.com/comprfi.htm

CL