AmateurRadio.com

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. 

Fair-Rite with 4 loops (4th on backside)

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.

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.

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. 

Pro-sound website 

K9YC 

N4XL

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.

 This weekend was the WAG (Worked All Germany) contest which I entered CW low power and unassisted. About 10 minutes into the contest things started to unravel, I was on 10m calling CQ TEST when my contest software (N1MM+) had the contact log window turn black. It came back to normal within an instant but that is never a good sign. Next, I pressed my F1 key to send CQ TEST again and it did not respond, I pressed it again and nothing. Then all of a sudden the rig keyed and the macro started to send...twice. Then the issues got worse as when I had a station come back to me and I responded with my exchange the macro would not send right away. It was very confusing to the answering station and as he sent his call again, it was then my exchange macro decided to send. 

It was time to shut down and get things sorted out. I  have had this issue in the past and thought I figured it out. In the past, my wired Lanovo mechanical keyboard was picking up RFI and causing me problems. I was looking for a fast fix and added some mix  31 toroids to where the cable enters the keyboard. I now have toroids at either end of the keyboard cable. 

I then fired up the contest software and called CQ TEST again on 10m. For over an hour, I  had no issues and hoped I had fixed the issue. This was the first time this issue had ever shown up on 10m in the past it has always been just  20m but of course now that I am contesting "MR RFI" changes things up.  Heading up to 20m and again while calling CQ TEST I had the N1MM+ contest log window go black again. It was time once again to shut things down as I couldn't contest in this situation. 

As I sat there and went over things I knew in the past I had had issues with my wired mouse, I went wireless and the problem was solved. Maybe it was time to go with a wireless keyboard? I have a Logitech K830 hanging around and thought I would put that into service and see what happens. Of course, the keyboard's rechargeable battery was dead and needed about an hour of charge time before I could use it. That gave me time to label the keyboard and look up the instructions on how to pair it. 

Logi wireless keyboard.

I was up and running again with the wireless keyboard and things were working just fine! This is a much smaller keyboard and I found myself hitting macro F keys when I was supposed to be hitting numbers. This also is not a mechanical key-type keyboard. I tend to be heavy-handed while my hands are resting on the keyboard waiting for the  CQ TEST macro to finish. The keyboard was so sensitive by mistake that I would type letters into N1MM+ call box. When this happened my CQ macro stopped (as it should) I had to lighten up my heavy hands while I was using this keyboard. 

While waiting for the keyboard to charge I made my way to Amazon and ordered a full-size mechanical keyboard. I was sure this was the solution to the issue and so far I was right. It was getting more toward evening and 40m looked like it was hopping. When I pressed my F1 CQ key my N1MM+ , Win4icom  radio control software and the web page I had open all disappeared! With everything restarted I tried again with the same results, it was time to pull the plug and think about things over the evening. The wireless keyboard was not the answer. It was time to get back onto Amazon and cancel the keyboard order.

Winkeyer with ground lead to main ground bus

I  began contesting and all was good on all bands, my fingers are crossed  BUT I have had this false hope in the past. Today (Monday) I have my weekly Medium Speed Contest (MST) in the morning and afternoon. It will be a good test to see if the issue has been fixed.
Also, I posted my issue on the Groups.io N1MM+ site and had some excellent feedback.  One common thread was the USB outer metal shell on the PC. I was told most of the time they are floating and not grounded and this can cause issues. I have a lot of USB cables connected to my PC for radio-related things. I was given a very good idea on how to ground them but more on that in another post. 

UPDATE: This morning and this afternoon I took part in the MST contest and called CQ on all bands without any issues. Maybe I have the RFI issue solved. BUT in the past I have done the happy dance to only be greeted with RFI....so we are keeping this celebration very low key. 

Here at VE9KK's household, my XYL has returned to part-time work from home and involves a computer and the internet to communicate regarding work. Last week while she was working and I was on the radio she told me her LAN connection kept dropping out. I did some experimenting and sure enough, it was my CW signal on 15m that was doing it. I quickly grabbed my last FT240-43 toroid and wrapped the CAT6 cable around it which did the trick! 

I then did some reading and learned that the CAT cable should be loose around the toroid and not tight as this affects the small wire inside the CAT6. I also read that 7 turns were the magic number of turns. Finally and this is the question to my readers I read two thoughts on wrapping CAT cable around a toroid. One school of thought was it is perfectly fine and the other was it slowed down the internet speed? I never did a speed check on my wife's connection with and without the toroid. The reason for this is she never complained the speed dropped so why poke the bear! Has anyone out there had an issue with your HF signal dropping internet connections at home and what did you do about it?