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 conditions for contesting were both great solar weather-wise and local weather-wise. The solar weather was very favourable during the entire contest which was nice. The sun has been very active these past few months and this weekend it was nice and calm. Local weather was just right for contesting as well...it was pouring rain and windy all weekend. Why is this great you ask..well during the contest slow periods no sun and the blue sky were calling my name to get outdoors. My goals for this contest were to have fun (check), run for 98% of the time (check), beat last year's score (double check) and hopefully have no radio or PC issues (check).

As always this was a very well-attended contest with lots of DX so even if you are not an avid contester there was an advantage to logging some rare DX. My radio was the Icom 7610 at 100 watts using the Hustler 4BTV vertical antenna. Max  CW speed was at 34wpm and toward the end I dropped it to 30wpm. For most of the contest, the Kp index was Kp3 and dropped to kp1 toward the contest end. The Bz index was in the plus for Friday and Saturday but headed in the negatives on Sunday. When the Bz dips in the negative numbers it accounts for problematic signal fading. At times the caller was there and then gone. 

I was very pleased all the way around,  the radio worked great, the PC and its software had no issues and the solar conditions behaved themselves. Mind you toward the end of the contest I  started to have a little brain fog and messing up similar CW letters such as H and S and on occasion transposing letters. This year I also made a point to not take things personally. What I mean by this is when asking for a few repeats because at my end I had either a close station wiping them out or another station calling me on top of the desired station. In the past when the station I was asking repeat from seemed to leave in a huff it used to bother me....well not anymore. In the past, I took things personally and that took the fun out of contesting....well no more. 

A very busy map of my contacts.

Some things that threw me off were stations coming back to me with "DE WXYZ". I would copy DE thinking it was the first two letters to only find out they were sending "DE" for "this is". I have my filter set for 400hz when calling CQ TEST and in crowded bands like in the CQ WW contest that is wide for me. I would have some stations come back to me way off my calling frequency. Most of the time I thought they were answering another CQ TEST close to me....but not so. I would end up adjusting the RIT make the contact and get back. But that was it and I am not by any means complaining just sounding off a bit. 

Well ok, just one more....those who when they send back their exchange would also send their call again which makes me think I messed up their call.  This became problematic when their call was "HSH" or "KH5" so made for unnecessary back and forth while others waited to contact me....or some would just step in with their call knowing the call was good the way I had it.  I also had fellow blogger Bas PE4BAS contact me during the contest as well.
When you hit 1750 CW contacts once you're done with the contest and in bed with your eyes closed you can still hear cw code in your head rolling around. I had a blast and am looking forward to the next contest.

Very happy with the outcome.

This coming weekend is the CQ Worldwide CW DX contest. You don't have to be a contester to jump in this contest. There will be some great DX  to be had so one can add contacts to an award you are working towards.  If you are a QRP op you can see how far your 5 watts will get you. At one time I even ran QRPp power and was amazed at the distances I made. The exchange in this contest is easy peasy a signal report (always 599) and your CQ zone. (Found here). If you are working your way up the contest code ladder this is a great time to log in some practice time. So double-click on your contest icon and roll in a few hours over the weekend in the contest.

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