RadioBanter - View Single Post

May 22nd 05, 03:01 AM

On 15 May 2005 11:00:57 -0700, wrote:

I'm looking for a solid desktop (either pizza-box or mini-tower)
computer case that has an all-metal exterior for shielding RFI. This
is for use around radios etc. I realize that SVGA monitors, mice, and
keyboard leak too, but right now I'm looking mainly at the PC box.

I haven't seen a case that wasn't metal. Some/most have plastic
fronts over the metal.

Most of the cheaper cases come pretty close to good shielding, but they
have these plastic filler panels in the drive bays that offer no
shielding and let a lot of RF leak out.

As do the expensive ones as well. The $30 - $40 ones I've used had
metal pieces that had to be removed from the 5 1/4" bays to use them.
Unfortunately when in use the drives have plastic fronts even if they
do have a metal chassis.

Most of the fancier cases in the computer stores around here have
humongous plastic pieces on the side. I'm looking for all-metal.

Standard is metal, fancy is a plastic insert with metal cross pieces
and a lighted fan for effects.
Surprisingly, those come with metal covers over the drive bays behind
the plastic ones in the front panel.

Rack-mount server cases seem to be pretty good in terms of metal
shielding all around but I need something for desktop use.

Any suggestions? If all else fails I can just put some perforated
metal over the holes in a cheap case, but I'd rather just buy a good
case to begin with.

Find a local computer store and look at the cases they handle. Look
them over and find which ones have the metal pieces over the drive
bays. They aren't inserts, they are actually part of the front
stamping and have to be broken out. Sorta like knockouts in
electrical boxes.

However, I doubt you will find much relief even with a full metal
case.

I built up all 4 computers we use here using standard parts.

Now, I have one of those with the plastic insert on the side setting
about a foot and a half below my rigs (Icom 756 Pro, Alpha 76A,
Alinco DR610T, and Kenwood TMV7A. The computer is an MSI K7N2Delta
Platinum with a 3.2 Gig Athlon, 1 Gig 400 MHz CAS-2 DDR Ram, 400 Gig
SATA RAID, and three EIDE 7200 RPM HDs totaling 920 Gig. The monitor
(19" CRT)sets directly above the two duobanders. About three feet to
the left is this computer which is the standard all metal case with an
MSI K8N Neo Series with a 3.4 Gig 64-bit Athlon, 2 Gig 400 MHz Dual,
DDR RAM.and about 650 Gig of HD space. (I don't have the SATA RAID
installed yet.) The monitor is a 17" NEC 1760v. Each computer is on
its own UPS.

All have the dual layer, high speed DVD R/W drives and are part of a
gigabit network that has two more computers. There is a 5 port
gigabit switch, router, and cable modem less than two feet to the left
of the duobanders and just over three feet from the HF rig. (I also
run the legal limit from 160 through 10)

I have no detectable interaction between the rigs and the computer
system in the house. The one in the shop will break the squelch if
you put the HT next to the case, or hold the antenna for the best
pick up, out to about 3')

I just brought the HT (VX-7R) in and the squelch did not open even
when touching the antenna to the individual computer cases.
I should add that right now the network is running near capacity with
backups across the network and several large downloads from the cable
modem.

My wife's computer is about 15 feet to the south (in another room)
and I do not hear it with the HT in there. The one is the shop is at
the end of about 115 feet of Cat-5e and I use the HT within a foot of
the monitor. That one is only a 2 Gig Athlon, but it too has 620Gig
of HD space and a 19" CRT monitor. Those too are MSI motherboards
with my wife's being a K7N2 Delta series and 2.8 Gig Athlon. I've
forgotten the model of the one in the shop, but it's the oldest of the
four. BTW, that case is also one of those with the plastic side
windows and lighted fan.:-))

Whether it's the motherboards, the cases, grounding, or a combination,
I don't know, but interference has not been a problem...unless you
count the electric fence across the road. Why I can not pick up the
computers at all in here, but can open the squelch out to about 3'
from the computer in the shop under ideal conditions I have no idea.
I think it's more of a crap shoot. Some high end systems bother as
bad as some low end systems while some low end systems cause no
problems.

All four computers run 24 X 7.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com

Tim.