Posts Tagged ‘RFI’
RFI issue solved!
February 5th, 2026 | 
Author: I decided to look into my internet connection setup. The motherboard I have for my PC does have WiFi via two small antennas on the motherboard. I am using a TP-Link extender in the hallway,
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| TP-Link extender |
which has a LAN connection. I attached a LAN cable to the TP-Link and plugged that into a TP-Link LAN switch beside my PC. From the LAN switch, one LAN cable went to my PC and the other to the Icom 7610 radio. I tried split toroids on the LAN cables and LAN switch power cable. That did not work. I then just used the WiFi connection on the PC to the TP-Link extender in the hallway—that did not work. I then connected my PC WiFi to the main WiFi from our router in the living room, thinking the TP-Link extender could be the issue, and that did not solve the issue.
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| LAN switch |
Whats your thoughts?
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| Possible RF magnet |
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| Needed connectors |
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| Connected and ready to go. |
I am at peace with the RFI gods.
The RFI black book
At the beginning of November, I posted regarding the journal I was going to start regarding my RFI. I wanted to log ideas to try, results from the ideas and detailed records of the RFI. In the past, it was scribbled on a paper here and there and when needed to refer to I could not find the notes. This was a great help and allowed me to track what did and did not work.
I then blogged on December 1st regarding ferrites I had purchased. They were bought and arrived in mid-November and I had a chance to give them a go. Now in my post on the ferrites, I did mention I purchased a brand called Fair-Rite, which I felt where a very good brand. I wanted to make the first test for this product an easy access one. I have mentioned in the past our electronic Maytag washing machine always had issues with RF from my operating. When I transmitted the washers would stop and just hummed. If the machine was not being used but still plugged in and I transmitted all the LED lights would come on and it would start to buzz. The only solution while operating was to turn off the power to the washer. In the past, I tried some snap-on chokes from MFJ and put them on the washers AC power cord, which did not work. I snapped on 2 of the Fair-rite chokes and to this day I have had no issues at all with the washing machine. The machine can sit there powered on or doing a load of laundry and no issues at all.
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| Fair-Rite with 4 loops (4th on backside) |
That was a very promising sign to me and I was thrilled to see such positive results. Back to my RFI journal. The only issue I was facing was my contest program N1MM+ while I was transmitting would freeze. I was not able to transmit a contest reply and that would prove frustrating. After a short time the program resumed but that could be 3 seconds, 30 seconds or a PC reboot. The other issue was my N1MM+ programs logging screen would go black and sometimes the whole program had to be rebooted for it to work again. I felt I had narrowed down the issue to my ground leads. I have 3 of them, the Icom 7610, LDG autotuner and the PC metal frame. Each of these 14 gauge green ground wires is fastened to a copper plate where the main ground is secured. I wound the ground wire 4 times through a clamp on the Fair-Rite toroid and also on the incoming number 6 ground cable (I put 3 snap-on ferrites on that as there was no way to wrap that size of cable). I spent the whole weekend on the radio in the CQ WW DX CW contest on all bands and full power. I did not have one issue at all. Since then, I have taken part in CWops and MST weekly one-hour contests without issue again. My fingers are crossed that I have found the right ferrite for the job.
Time to “Fair-Rite” out the issue!
Order bulk and save!
Those of you who are regular blog readers know I have had my fair share of RFI that has affected my PC, washing machine, headphones and key. I have been doing some reading that all ferrites are not alike. Yes, they may be a mix 31 but there are good and very good ferrites on the market. I looked around at the popular dealers that dealt with chokes both beads, snap on and rings. I have read many good reviews on the Fair-Rite brand of ferrites. There were two electronic dealers I have dealt with in the past Mouser and Digikey. Mouser was where I ended up as I had ordered from them and was very happy. I found the Fair-rite snap-on chokes I wanted and ordered them along with one Fair-rite round ring ferrite. These items shipped the same day and were at my door in no time. My mission with the new ferrites was to solve my PC issue. When operating N1MM+ contesting program now and then (mostly at the most inconvenient of times) the Windows hourglass would pop up on my screen. For anywhere from 4 seconds to 20 seconds I was not able to transmit using any of N1MM+ macros. Not good when a station is waiting for a contest reply from me. The other thing that happened again in N1MM+ the log window would just go black. The only way to solve this issue was to restart the program.
I have an idea what the issue may be and I want to see if this Fair-Rite product is truly a quality product or not. More on that in the next post.
Front USB ports on your PC.
The finished product.
Once a year I take some time to open up my PC and give it a nice cleaning out. I am shocked at how much dust collects just after one year. I built the system and spent some money on it so I want to do my best to look after the upkeep. My computer is tucked off to the side of my desk on a shelf built for it. Taking it out is a chore and I have to make sure each USB cable goes back exactly where it was removed. If not when I start my virtual com port program I get an error message that certain com ports are not working.
I have been doing some reading on RFI these past few months and along with that comes the subject of grounding. One topic that came up over and over again was the front USB ports that some PCs have. Mine has such ports and it has been mentioned that most of the time these ports are not grounded to the chassis of the PC. They in most cases are grounded to the motherboard via the control cable that makes its way out to the USB front board.
Sure enough, my PC was one that did not have a chassis ground for the front USB ports. It was easy to do and was a jumper wire from the USB board to the PC chassis. At the time I had no green wire and had to use red but I will know what it is for. While I had the PC open I did check the onboard USB ports and I have 11 of them and they are chassis grounded.
What does RFI have to do with Pins…….
I have been doing some RFI investigating, which has sparked my interest because I have been having some RFI issues of my own. In my travels, I have read of something called Pin 1 problem. I went to a few websites about this and had a glance here and there but never looked at it closely. This past week I did a bit more of a deep dive regarding the Pin 1 problem. The name came from Neil Muncy in 1994 he wrote a paper entitled Noise Susceptibility in Analog and Digital Signal Processing Systems. In it, he describes how he found the common XLR connectors used in the audio industry pin 1 was always connected to the cable shield connection. The audio gear would connect equipment pin 1 to the equipment metal enclosure, over time Neil noticed that this practice stopped and pin 1 shield ground was being connected to the circuit board common trace and somewhere on the circuit board the common trace had a jumper wire to the chassis ground. This allowed the RFI that was picked up on the shield of the audio cables to travel. As Jim Brown K9YC puts it:
"If the shield goes to the shielding enclosure, current stays outside the box. If the shield goes to the circuit board then the current gets inside the box!"
In the ham radio world, we use computers, external sound cards, USB hubs and ham rigs. All these could have a Pin 1 problem that may be our thorn in the flesh. Now when I say "pin 1" problem with our gear there may not be a pin 1 used for shield grounding like the XLR audio connector the issue is the shielding or ground pin on the connector does not go to the case ground but to the circuit ground and then to case ground. The label of Pin 1 came from as said earlier the audio XLR connectors pin 1 with was always the shield connection pin. When dealing with radio gear it's not Pin 1 per say but the connector ground connection does it go to the chassis but to the circuit board to possibly cause issues.
If you find your radio gear has a Pin 1 issue such as your headphone plug metal housing does not go directly to the chassis ground but to the circuit board most times you don't want to get the soldering iron out to fix it. If stray RF is let's say getting into your USB cable from your rig to PC for rig control and you find you are having issues. I would suggest you first look at the grounding a bonding of your gear, it is a quality USB cable as all are not made alike. Finally, try a quality ferrite on the USB cable if it is stray RF is going places it should not. I mention ground and bonding of your gear because if your gear has proper chassis grounding but you either do not have it grounded or it done incorrectly you could be compounding your RFI issue.
I did look at my Icom 7610 shop repair manual and most if not all critical RF potential grounding is chassis grounding. On the other hand, in my personal PC, well many items are routed to the circuit board ground and then a jumper to the chassis ground. As K9YC put it regarding my PC "current is getting inside the box".
So the Pin 1 problem is something for us to be aware of and to consider when going after RFI. Now when I say RFI I am including both reception issues and equipment acting up.
Below are some great reads regarding the Pin 1 problem.
Time to bring out the black book
In the past, I have like others had issues with RFI. When RFI's ugly head pops up I find myself wondering what I have tried in the past. If you are like me you have a hard time remembering if you had tried something and if so what happened. I decided it was time to roll out the black book. I will use this book to record what I have done, the results, and the steps I want to take. Recently I felt I had my RFI issue resolved but on Monday while taking part in the Medium speed CW contest I had N1MM macros freezing. The encouraging thing is this issue happened in the past and was terrible, now it hardly happens and gives me the impression I am slowly solving it. I have a few more ideas to try and the black book will help map a path forward in the journey.
