[Yaesu] RF quiet computers

[Hsu, Aaron (NBC Universal)]

John,

The PC's switching power supply is a major contributor to RFI from a computer.  Many cheap "lightweight" supplies have few or even lack any type of input or output filtering.  First thing I would do is replace the power supply with a better quality one (or take it apart and start adding bypass caps and chokes).  Not all power supplies are built the same.  I prefer PC Power and Cooling supplies (http://www.pcpowercooling.com)- well built and they don't skimp on engineering.  Good alternatives are Antec's "True Power" or "NeoHE" series and higher-end Seasonic supplies, but I haven't done much RFI testing on either.  I use various PCPC and Antec supplies in my computers at home and don't notice much RFI, but I live in a suburb of Los Angeles (6 miles from Downtown), so local PC generated hash is minor compared to all the other crap from the city <g>.  My laptop's power brick usually causes more RF hash than the other PC's combined.

Another thing to do is make sure you have a well shielded case (lots of sheet metal with good connectivity).  Also make sure that *ALL* cables comming out of the PC have an RF choke attached as close to the PC as possible (and better if also at the other end) - snap-on chokes often work OK.  UTP ethernet cables may be an exception as the chokes may hamper performance - test before and after attaching chokes.  UTP is balanced anyway, so it shouldn't radiate much.

73,

  - Aaron Hsu, NN6O


-----Original Message-----
Sent: Thursday, November 29, 2007 9:37 AM
Subject: [Yaesu] RF quiet computers

Recently, I discovered how RF noisy my fairly recent
ebay purchased laptop is (an Acer Pentium III).  It
replaced a Micron Pentium 120mhz computer which was
very quiet on the radio, but also kind of slow, and I
thought a laptop would be nice in the shack because it
would mean less wires, etc.

I find that it really raises the noise floor on 80,
somewhat on 40, and on parts of 20 and 15.  It is
probably bad on other bands as well, but I really
haven't experimented with them yet.

So I probably need to get a replacement, unless anyone
knows how to kill this noise. What are some good, RF
quiet computers to look at? I don't have alot of money
to spend, but can come up with a little bit.  Speed
probably won't be that important, as long as I can use
it for some of the digital modes.  The Micron
unfortunately died, or I would hook it back up.

73s John AA5JG