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eHam Forums => RFI / EMI => Topic started by: VE3TMT on March 10, 2006, 04:06:32 AM



Title: Interference from my monitor
Post by: VE3TMT on March 10, 2006, 04:06:32 AM
Just my luck, on 7.070 I get interference from my computer monitor. I know it's the monitor because it disappears when I tun it off. I can hear it with the rig switched to the dummy load, the MFJ unit not me! This morning I thought I would start unpluuging things to see if it was coming in from a cable. I disconnected the serial cable into the rig, nothing. I thought I would unplug the monitor from the computer, so when I turned the florescent light on above my desk the noise goes away. Turn the light off the noise comes back. I'm stumped, why would turning the light on and off affect the monitor? If I have to work with the light on no trouble just curious why it does this.

Any ideas?

Max VE3TMT


Title: Interference from my monitor
Post by: KC2MMI on March 11, 2006, 03:02:57 PM
<<I'm stumped, why would turning the light on and off affect the monitor?>>

I'd guess that either the light is changing the local ground via the power line, or maybe when it is on, it is absorbing EMF from the monitor (i.e. if there's a magnetic ballast coil in the lamp) when it is on, so it may be magnetically coupled, "grounding" the magnetic field from the monitor.

If you move the light, and it still works the same way, then the problem is in the AC lines, not in any odd coupling.


Title: Interference from my monitor
Post by: KG6QKJ on March 26, 2006, 10:07:33 PM
Change the refresh rate of the monitor in the control panel.  It WILL move the birdie to a different freq.

73,
Marty
KG6QKJ