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Author Topic: RFI to Computers from RIG  (Read 429 times)

N8XI

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RFI to Computers from RIG
« on: June 09, 2021, 04:38:14 PM »

Grounding

It’s amazing what a couple of well placed grounds will do.

I have been using computers for a long time logging, contesting, digital, etc.
I decided to ground my Tower PC and LapTop.

Finding a bare screw on the Tower PC was easy.
I had to research how to ground the LapTop USB port.
I chopped one of my short, not being used USB cables and spliced/soldered a #12 Green (it’s gotta be green ;D ) wire to the ground wire of the chopped USB cable.

Then connected the Tower and Laptop grounds to my ground buss.

Wow! No more blinking screens, losing the laptop every so often from the RFI, etc…
There are rules to follow in Amateur Radio and if you skip a few you pay the price 
73, Rick – N8XI
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K6AER

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Re: RFI to Computers from RIG
« Reply #1 on: June 10, 2021, 11:16:45 AM »

When you start to place grounds on intrinsically ungrounded equipment, which are eventually connected to the home ground, you must place a surge protector on the home main AC feed.

A lot of computer equipment is floating in reference to a AC ground.   By grounding the equipment for RF purposes you are exposing the equipment to power company AC surges. With your equipment connected to ground your laptop, printer, etc. becomes a fuse in the case of a AC power line surge.     

A better way to handle RF getting into computer support gear,  is to use RF toroids in the power leads and on the connection cables. Shielded lines only work when they have a low impedance path against RF energy. Once you start grounding equipment not made for AC common grounding you must go all the way to protect your equipment.

On a larger scale, it is best to move the antenna away from the shack location.
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GRUMPY2021

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Re: RFI to Computers from RIG
« Reply #2 on: June 10, 2021, 11:51:10 AM »

Better hook a green (got to be green) wire to yourself if that much RFI in the shack   Now how to do you stop the noise your monitor(s) generate?
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N8XI

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Re: RFI to Computers from RIG
« Reply #3 on: June 11, 2021, 05:28:09 AM »

When you start to place grounds on intrinsically ungrounded equipment, which are eventually connected to the home ground, you must place a surge protector on the home main AC feed.

A lot of computer equipment is floating in reference to a AC ground.   By grounding the equipment for RF purposes you are exposing the equipment to power company AC surges. With your equipment connected to ground your laptop, printer, etc. becomes a fuse in the case of a AC power line surge.     

A better way to handle RF getting into computer support gear,  is to use RF toroids in the power leads and on the connection cables. Shielded lines only work when they have a low impedance path against RF energy. Once you start grounding equipment not made for AC common grounding you must go all the way to protect your equipment.

On a larger scale, it is best to move the antenna away from the shack location.

Michael, K6AER
You have assumed quite a lot!
I have a Single Point Ground.
I have had surge protectors forever.
Commercial Western Electric Surge Protectors from a telephone office tear out.

I am using Clamp On and Thru Hole toroid's in several locations.
Which were on the PC & Laptop prior to my added grounds.

Sorry I can not move my antennas. I live on a suburban lot.
My Cushcraft A4S w/40M Yagi is on a roof tower about 40 feet away and my 80M Invert V is hanging just below...The Inverted L about 20 feet further north.

73, Rick - N8XI
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N8XI

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Re: RFI to Computers from RIG
« Reply #4 on: June 11, 2021, 05:39:19 AM »

Better hook a green (got to be green) wire to yourself if that much RFI in the shack   Now how to do you stop the noise your monitor(s) generate?

Sorry GRUMPY2021 I shouldn't answer you!!
No name or call indicates your hiding to pounce on others!
What? You think I am stupid? Why would I hook up any type of wire to myself if I have RFI in the shack, Which I don't!
I have noise from monitors? Can you please specify what frequencies and give me your expertise on how to alleviate such?

The world is full of bunny rabbits, try to be a better one!

73 or 88 or 161, whichever floats it!
Rick N8XI, KN8RHM & WA8RXI since 1959
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G8FXC

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Re: RFI to Computers from RIG
« Reply #5 on: June 12, 2021, 01:55:50 AM »

This is the reason (well, one of the reasons) why I will not use a laptop in the shack - they are difficult to ground effectively. I have fought a running battle against RFI crashing my computers for years. Lots of torroids on all the cables helped a lot, but never completely fixed it - the thing that finally banished it was running a good copper braid from the case of the mini tower to the shack RF ground.

Martin (G8FXC)
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N8XI

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Re: RFI to Computers from RIG
« Reply #6 on: June 12, 2021, 05:06:29 AM »

Here is a good grounding article by Dave, N9KMY
I had ground loops while back. They are fairly easy to fix once you know what to look for.

http://www.w4olb.org/files/documents/Ham%20Station%20Grounding%20(1).pdf

73, Rick - N8XI
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N6YWU

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Re: RFI to Computers from RIG
« Reply #7 on: June 12, 2021, 04:57:33 PM »

This is the reason (well, one of the reasons) why I will not use a laptop in the shack - they are difficult to ground effectively.

The problem isn't that a laptop isn't grounded, but that it is incorrectly grounded through multiple connectors, both the USB port and other connections, such as the power cord.  The solution is to use neither, since USB isn't designed for use across high RF voltage potentials.  Get a rig capable of a network connection, and use WiFi or a fiber optic connection to completely isolate your transmitter and computer.
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G8FXC

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Re: RFI to Computers from RIG
« Reply #8 on: June 16, 2021, 04:50:19 AM »

This is the reason (well, one of the reasons) why I will not use a laptop in the shack - they are difficult to ground effectively.

The problem isn't that a laptop isn't grounded, but that it is incorrectly grounded through multiple connectors, both the USB port and other connections, such as the power cord.  The solution is to use neither, since USB isn't designed for use across high RF voltage potentials.  Get a rig capable of a network connection, and use WiFi or a fiber optic connection to completely isolate your transmitter and computer.
I'll grant you that USB does not cope well with high RF fields, but I can crash my laptop in the shack with it running on battery, so it's not multiple grounds. I fought a long battle against RFI in the shack and got it almost under control with a lot of ferrite on every cable, but the thing that finally banished it was earthing the metal case of the PC to the shack RF ground.

Martin (G8FXC)
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AC9XH

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Re: RFI to Computers from RIG
« Reply #9 on: July 18, 2021, 06:54:08 PM »

If you want to properly ground your laptop or tower and not be a fuse so to speak, run a separate wire to your tower or laptop housing or chasis screws with a ring connector and then run it out thru the wall or window to a separate ground rod. simple.also if your computer is crashing due to rf in the shack, look for swr problems or take thin cardboard and put aluminum foil on side facing rigs kind of like building a faraday shield and when you ground your computers with the separate ground rod with wire, it should help significantely.When i crank the power i get the same thing also. i built abox lined with foil that sits around my laptop and the foil has a screw going into it to a wire out to its own ground rod. actually a aluminum pipe driven into the ground. works great.All my equipment is not tied to house ground. They all have their own separate rod and conductor.
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