Computer interferes with radio. Please help
 

I just got my computer back and a new power supply was installed. The
system always interfered with my radio, but now it interferes so much,
I can't pick up anything on the MW band.

I can't open my box because it's sealed and I would void my warranty.
I can't take the box back right now because I'm working on deadline.
Is there any other remedy for this? Both radio and computer need to
be in the same room.

Any help would be greatly appreciated.:)

In article ,
(mark) wrote:

I just got my computer back and a new power supply was installed. The
system always interfered with my radio, but now it interferes so much,
I can't pick up anything on the MW band.

I can't open my box because it's sealed and I would void my warranty.
I can't take the box back right now because I'm working on deadline.
Is there any other remedy for this? Both radio and computer need to
be in the same room.

Any help would be greatly appreciated.:)

There are two ways the computer noise gets into your radio EMI and RFI.

EMI or conductive noise comes in through the radios power cord. Use a
power line noise conditioner on the computer. You might want to use a
separate one to plug the radio into.

RFI or radiated noise is picked up by the antenna. Have your antenna
located outdoors and brought in to the radio with coax. Use a low noise
type antenna. If you have a random wire use some type of transformer so
a separate antenna ground can be used.

In addition you might find it necessary to use a choke on the coax so
the computer noise does not make its way from your operating position
down the coax to the antenna.

--
Telamon
Ventura, California

What kind of noise do you have?

If it's spurious signals/carriers, then it might be that power supply! (that's
what mine did - generic 233mhz PC).

My powersupply used the power cord as it's antenna making my whole system of
power cords radiate the birdies. Ferrite cores did nothing to help me.

Grounding the PC case to it's own ground rod helped about 10db. That was
better, but still most of the AM band was shot.

What got rid of 99% of the carriers on medium wave, was to open the bugger up,
and put high voltage bypass caps from the rectifier to ground (.1mfd). I also
put the same caps from the power cord to ground, and then wrapped all wires
comming from the powersupply to various internal parts, around Radio Shack
ferrite cores.

I now only have a half dozen weak carriers on long wave and medium wave, and
they are only about S6 using an external antenna and now I can use my PC for
recording my DX sessions.

Unfortunately, you would have to have the shop open up both the computer and
the powersupply to modify it. Not sure if they'd do that for you.

Good Luck !

John Wilke
WB9UAI
Milwaukee

I had the EXACT same problem a month ago. I had to replace the power supply in
my computer, and the noise was horrible.
Normal noise was at about s4, and when I turned on the computer, the noise
level went up to about +20db on the signal strength meter. The only solution
that worked for me was replacing the power supply. I tried antenna changes,
ferrite chokes, and grounding the Computer cabinet.....none of that helped.
Good luck, and hope you find a power supply that works out.

I have sold/repaired hundreds of computers for various businesses and have
never heard of a "Warranty Void" sticker on a case. What business did you
get it from so I can warn people about them?

--
Gregg
*It's probably useful, even if it can't be SPICE'd*

I've encountered the same problem.
They (PS) are all made in China now
and they are so dammed cheap with
no bypassing and components haphazardly
placed all over. I'm using an older Compaq
Presario in the radio room which is the
most RF-quiet machine I have. The white-box
PC's you see for sale
at computer shows are the worst offenders.
I am suprised that FCC and UL have not clamped
down on these traveling PC Sellers with their
non-Part 15 non-type accepted and inherent
electrical hazard junk.



"mark" wrote in message
om...
I just got my computer back and a new power supply was installed. The
system always interfered with my radio, but now it interferes so much,
I can't pick up anything on the MW band.

I can't open my box because it's sealed and I would void my warranty.
I can't take the box back right now because I'm working on deadline.
Is there any other remedy for this? Both radio and computer need to
be in the same room.

Any help would be greatly appreciated.:)

I just got my computer back and a new power supply was installed. The
system always interfered with my radio, but now it interferes so much,
I can't pick up anything on the MW band.

I can't open my box because it's sealed and I would void my warranty.
I can't take the box back right now because I'm working on deadline.
Is there any other remedy for this? Both radio and computer need to
be in the same room.

Any help would be greatly appreciated.:)

HOW MUCH $ SHOULD EACH OF US SEND?

"mark" wrote in message
om...
(mark) wrote in message
. com...
I just got my computer back and a new power supply was installed. The
system always interfered with my radio, but now it interferes so much,
I can't pick up anything on the MW band.

I can't open my box because it's sealed and I would void my warranty.
I can't take the box back right now because I'm working on deadline.
Is there any other remedy for this? Both radio and computer need to
be in the same room.

Any help would be greatly appreciated.:)


I want to thank all who responded.:) Lots of great ideas here.:)
Just as an update, I grounded the computer. Since I'm living in an
older home, there are no three prong outlets with ground. The family
biz is a machine shop, so I asked my brother for some help. He
grabbed a piece of copper rod about 1/4" diameter x 3 feet, drilled a
hole, threaded it, got some copper grounding wire, the whole bit. I
attached one end of the wire to the back case where the exhaust fan is
(I believe it's connected to the power supply..connected right on a
metal part) and the other end to the stake now pounded into soil just
outside the window. Turned on the radio, (Pioneer receiver, metal
casing), fired up the computer....noise, noise noise. Ah, well. Time
to take the next step.
As I understand it, it will probably be helpful to have my computer
grounded anyhow. so, I'll just keep the ground connected. With all
the rain, flooding and storms we've been having in NE Ohio, the
ground will be good insurance if I get a nearby lightning strike.:)

mark

1. Try winding audio cables as a coil onto one or more ferrite cores.That
should help.
2. buy a good computer case (metal)
3. You can also do this for your computer cables if problem still not
solved.