AmateurRadio.com

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.

For the ARRL  Sweepstakes contest the exchange is the following... let's take my exchange for example:

112A VE9KK 89 NB

To break it down 112 is the serial number so the station I contacted is the 112 contact for me. 

The letter A  (called precedence) signifies low power (more than 5w and not more than 100w)  in a single op. Other letters are Q for QRP, U for single op unlimited power, M for multiop and S for school. 

Then you send your call VE9KK

89  (called Check or CK) is the year I was licenced 

NB (called Section or SEC)  is the province. 

Now think of all that info coming at you in some cases 32 to 34wpm. In this contest, it is very advisable to slow down to the station you are contacting speed. If not you will use up lots of time with repeats. 
Now once you send all this you may be asked to resend any one or combination of your exchange as it may have been missed. For example, you may hear PREC, CK? I would then resend A and then 89. 

Now the contest software from records most of the time fill in the stations CK, and SEC  BUT sometimes it's wrong and it has to be changed on the fly.
My effort was part-time as I could not spend any time on Saturday evening it was only late morning and part of the afternoon I was able to take part.
This is a great exercise for your CW skills!

 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. 

Last evening we were treated to a nice light show courtesy of the active sun.  

Yours truely

In a previous post, I mentioned I had purchased a Zachtek WSPR desktop transmitter. I found a great site one can use to go over the data collected regarding your WSPR transmissions. The site is called Grafana  GUI and can be accessed at the WSPR live site. The Grafana dashboard gives you information on solar weather from 5 minutes to 1 year.   Station-specific information such as antenna radiation pattern, spot data per band and time, map of where your signal is heard and finally it can be used for receiving and transmitting signals. I use the TX  data as I do not yet have a stand-alone WSPR receiver. There is a ton of information you can gather, my advice is to visit the site and look around. I ran my WSPR transmitter for almost 24 hours and below I  have included the Kp index for that time period as well as the antenna radiation pattern of my Hustler 4BTV. 

Click on all pictures to enlarge.