Radio Interference

is the box tight? all the card plates in place, no holes? you need metallic shielding...can you try putting pc under metal desk...?

I agree with the first answer. And there's also a possibility that the interference orriginated from the Convenience aoutlet that the appliance/s are sharing with. Try using the radio in a different branch of electrical circuit. Outside the room for example.

Hope this helps.

You sure it's not the wiring in the building? One way to test is take a battery operated radio into the room and start up the machine.

It is a 1 room office in a downtown building. Probably 10 x 20'. It has 2 computers. Before I replaced the computer she had no problem with the radio. So I would assume it is something in this computer. I have tried a radio in all different outlets in room with no help.

It is true if the connection of both Radio and the PC are together on this same box. i had a similar experience before whenever I put on my PC when Radio is already working.You need to connect the PC and Radio in a separate outlet socket.

What has happened, is that the new PC has a clock frequency that is either near the radio stations frequency, or is beating with the "local oscillator" in the radio.

The only "fix" is extreme shielding techniques.

1. Make sure that the case is grounded.
You may even want to run a dedicated ground wire from the case to earth ground.

2. Make sure that ALL openings in the case are covered with metal.
Unused drive bays are often open wave-guides for radiated RF.
If the holes for the cooling fans look to be large, install some copper screen over the openings. Use screws to assure the screen is connected to the case.

3. Attach clip on ferrite beads to EVERY wire that comes out of the PC as close to the case as possible. Some cables have these built-in. You can tell by the large lump in the cable near the connectors.

4. Make a grounded metal box to place over the PC. Copper mesh would be the best material to use.

Chas

You problem is more than likely the Monitor. Turn off the monitor, does the noise (interferance) go away? If so you need to check the A/C wall outlet the monitor goes to and make sure it is a 3 prong type and that the third wire hole does have a good ground connection. The video cable from the video card to the monitor should have a large ferrite bead on it, thats the bulge on one end (usually the pc end). If this is an old monitor replace it or have it fixed. If it does not go away with monitor off then make sure the PC line cord is good (the green wire makes good ground at the wall socket) Grounded metal case in the computer is very good shield against radio interferences. When the case not properly conncted to the ground, the shielding is not as good as it was designed to be. When the PC is not connected to grounded outlet, it's operation can be more easily disturbed by external radio interference and electrostatic discharges. DO NOT cover holes on your PC it will overheat and that will not solve the problem with electrical noise. Make sure all the case screws are in and tight. Try a battery powered radio to isolate the route of the noise, radiated through the air or transmitted through the AC line. You have to first isolate the principles involved. monitor versus PC as cause, Battery powered radio versus a/c operated radio as being effected, correct grounding of the radio, on back of the radio is probably a connection with a ground symbol. Ground that to the a/c receptacle coverplate screw. Does it affect the TV sound (FM) or picture (AM)? Just the radio? Does tuning around the band change the severity? So two things to figure out first is the mode of transmission, power line or radiated (could be both.)

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