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Question

Walkie-Talkie Causing Interference with PC

Mar 20, 2018 11:49AM PDT

I work at a retreat center and we use Motorola walkie-talkies to communicate across the property. We recently moved to a new office and now my coworker's monitors blink off for several seconds whenever a walkie-talkie is used within 8-10 feet. This has never happened before, even when using the radio while sitting at his desk. My PC is within 2-3 ft of his and never has any issues.
Upon doing a little research, I found out that it's possible for radio waves to interfere with PCs, but very little has changed about his set-up, so I have no idea why it's a problem now but never before.
He has a Dell Optiplex 3020 with an Intel i5 processor and is running Windows 7 Professional. The only changes are that we added a third monitor (all Dell monitors) via a USB to HDMI adapter and put the monitors on a triple monitor stand.
At first, I thought that the metal monitor stand was acting as some sort of antenna, but if that is removed, the issue persists. I've added a number of ferrite chokes to the HDMI and VGA cables, but they don't make any difference. Anyone have any ideas what the issue is?

Discussion is locked

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Answer
You've already shared the issue.
Mar 20, 2018 12:09PM PDT

What you are really asking for is a cure. Sadly it's never a sure fix unless we reduce what parts are receiving that interference signal reception capability. I see you already tried chokes but you may have to go back to what worked before. Drop the third monitor as a test.

Remember you are talking RF physics here. That radio emits a signal and something is receiving it and getting upset about it.

To resolve is going to be specific to that setup. If you are unlucky that the issue is compounded by a reflection of the RF source that doubles the power then simple solutions will not solve this. You may have to swap in another PC that is more immune to the source.

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Troubleshooting
Mar 26, 2018 5:23AM PDT

We did try unplugging two of the monitors and just leaving one plugged in, but the remaining monitor still blinks off. Is there any way of telling what the RF signal is affecting? Or even an educated guess? Could it be the HDMI or VGA cables or something within the PC tower itself? Are there materials that would work to shield the cables or tower?

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Sorry no.
Mar 26, 2018 6:52AM PDT

Since it's not my office and even with my background in electronics, antennas and more, I feel you want an sure fix. In remote help like this you are stuck with trying another system, or trying cables and machines to see what works better.

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Gotcha
Mar 26, 2018 7:12AM PDT

Gotcha, so try a bunch of different things and see if anything works... Thanks for your time!

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Answer
As a test
Mar 20, 2018 9:25PM PDT

One monitor direct connected to the pc.

Get the other 2 monitors and the adapter and cabling out of the mix.

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Troubleshooting
Mar 26, 2018 5:23AM PDT

We did try unplugging two of the monitors and just leaving one plugged in, but the remaining monitor still blinks off. Is there any way of telling what the RF signal is affecting? Or even an educated guess? Could it be the HDMI or VGA cables or something within the PC tower itself? Are there materials that would work to shield the cables or tower?

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Just unplugging the monitors
Mar 27, 2018 3:32AM PDT

might not solve the problem. Something is acting as an antenna for the walkie's signal, so remove the leads that connect the monitors, too. Remember this is just a test as Mr Proffitt states. Until the "antenna" is found, nothing can be ruled out until it is removed from the setup. Sometimes it could be the way the cabling and leads have been arranged VS the way they were in the old setup, so try moving the way the leads lay together.

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Answer
Problem Solved
Apr 16, 2018 11:06AM PDT

So I was able to identify and fix the problem! I did a bunch of moving stuff around and plugging in and unplugging of monitors and trying different configurations. Whenever a certain one of the display cords (a DisplayPort to VGA) was plugged in, it caused the interference, whether it was plugged in by itself or with the other monitors. I switched it out for a DisplayPort to HDMI cable and problem solved!

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Thanks for the update. A thought.
Apr 16, 2018 11:50AM PDT

By moving away from Analog video, you moved to a more immune video system.