AmateurRadio.com

 The antenna I have is the Hustler 4BTV, and I have owned it for about four years. I had been noticing that after a couple of days of rain, the SWR on 15 meters would increase.As the weather warmed up, the problem disappeared. My suspicion was that water was making its way into the 15-meter trap and causing the SWR issues.

I waited for a forecast of a few nice, dry days before taking the antenna down for inspection. The first thing I noticed was that I had accidentally covered the drainage slots at the bottom of each trap with electrical tape. If water was getting into the traps, those slots were intended to let it drain out. My first course of action was to remove the tape from all three traps.

Tape removed from drainage slots

I started with the 20-meter trap, then moved on to the troublesome 15-meter trap. As soon as I removed the tape from the 15-meter trap, a small amount of water drained out. I then removed the tape from the 10-meter trap, and like the 20-meter trap, no water came out.

Each trap has a plastic cap at the top that helps keep water out while also insulating the trap tube from the center antenna element. This seemed like the most likely place for water to enter the trap, so I decided to disassemble the 15m trap for a closer inspection.

Before taking anything apart, I carefully marked the position of the tubing so I could reassemble it in nearly the exact same location. My hope was that this would keep the antenna's SWR very close to where they had been. See above drainage pic for position marking in red. 

After removing the 15-meter trap from the antenna, I took off the plastic cap and inspected it closely. I couldn't find any visible damage, but I know that water can find its way through even the smallest of gaps. That alone could have been enough to cause the SWR problems I was seeing.

Outer tubing showing water drops

With the cap removed, I looked inside the trap and found several small water droplets. I then removed the outer trap tubing so I could inspect the trap winding and all of the electrical connections.

Fortunately, everything inside the trap was in excellent condition. The winding and all of the connections looked perfect, which reinforced my belief that moisture—not corrosion or a failed connection—was the source of the problem.

After thoroughly drying all of the parts, I noticed the original bead of silicone that had been applied during manufacturing. When I first tuned the antenna after purchasing it, I had to slide the 15-meter trap's outer tube to adjust its resonant frequency. My guess is that this movement disturbed the original silicone seal. If so, it was probably only a matter of time before water found its way inside. I was actually surprised it took four years for the problem to appear.

15m trap condition

When I reassembled the 15-meter trap, I applied non-acetic, neutral-cure silicone around the plastic trap cap to restore the weather seal. While researching the best product to use, I learned that not all silicone sealants are the same. Silicone that smells like vinegar releases acetic acid while curing, which can promote corrosion on aluminum. I certainly didn't want to solve one problem only to create another.

The product I chose was GE Silicone II, which is a neutral-cure silicone and safe for use on aluminum. I happened to have an older tube on hand, but I noticed the silicone had turned yellow.  I never realized that silicone could age over time so I purchased a new tube of silicone.

With the trap reassembled, it was time to tape the joints where the antenna sections fit together. While I'm not an expert on silicone sealants, I am very familiar with electrical tape after spending my career as an electrician. Not all electrical tapes are created equal. For this project, I chose 3M Scotch Super 33+, a premium tape well known for its excellent UV resistance, flexibility, and long-term outdoor durability. Rather than list all of its specifications here, you can simply click HERE to learn more about it. 

With the antenna back in the air, I went inside to check its performance. The results on 40, 20, and 10 meters were exactly as expected. Unfortunately, I had created an entirely new problem on 15 meters!

I had solved one issue, only to create another. Fortunately, I have almost solved this new problem. In my next post, I'll explain what happened and how I fixed it.

Without any RFI issue.

In my last post, I was on the receiving end of RFI—you can read about that HERE. This post is about being on the other side of the equation: being the source of the RFI.

I have a Raspberry Pi 4B running Open HamClock Backend. It's a very handy program that provides a wealth of useful operating information. During the Canada Day Contest last week, I noticed that whenever I transmitted on 15m at 100 watts CW, the monitor connected to the Pi 4B would go completely blank. As soon as I stopped transmitting, the display would immediately return.

Blank monitor screen.

This time, instead of being the victim of RFI from a noisy wall wart, my own RF signal was causing the problem. You could say I had become the RFI source.

It was time to investigate. My first suspicion turned out to be correct—the HDMI cable running from the Pi 4B to the monitor. I had a spare Mix 31 ferrite toroid, so I wound a few turns of the HDMI cable through it. The problem disappeared immediately. That quick fix allowed me to get back to contesting, knowing I could look into the issue more thoroughly later.

The Raspberry Pi 4B came with an HDMI cable, but I assumed it probably wasn't the highest-quality cable available. I examined it closely but couldn't find a manufacturer, model number, or even a country of origin.

Old HDMI cable

All of the USB cables in my station are made by Tripp Lite. In total, I now have seven Tripp Lite cables in service performing various tasks. I've never had an issue with any of them, and they have consistently earned an excellent reputation for quality. Based on that experience, I ordered a Tripp Lite HDMI-to-Micro-HDMI cable for the Pi 4B. Yes, I could have simply left the ferrite toroid on the original cable, but I prefer to solve a problem at its source whenever possible.

So, what makes the Tripp Lite cable better? It features excellent shielding, heavier-gauge conductors, superior overall construction, and is backed by a lifetime warranty.

New Tripp-Lite cable

When the new cable arrived, I removed the ferrite toroid from the original cable and repeated the test. As expected, transmitting on 15m caused the monitor to go blank once again. I then replaced the original cable with the new Tripp Lite cable—without using the ferrite toroid—and transmitted under the same conditions. This time, the monitor remained stable with no blanking whatsoever.

Another RFI adventure solved through a little troubleshooting and some simple testing. Sometimes the simplest solution really is the right one.

LED RFI

Where we live, I have a very quiet noise floor and have enjoyed it for years. Recently, however, while operating on 40 meters, I noticed an offending signal on the Icom IC-7610 waterfall display. The noise repeated approximately every 15 kHz. If a CW signal happened to fall within the hash, I was unable to hear it.

I tried using the radio's noise reduction feature, which reduced the interference somewhat. However, increasing the noise reduction too much tends to distort CW signals, so that was not a satisfactory solution. I also tried the noise blanker, but it had no effect on the noise.

I began to think about what had recently changed in our home. Sure enough, my wife had recently purchased an LED light for her sewing table. As a quick test, I turned off and unplugged the new light. Immediately, 40 meters returned to its normally quiet state. When I plugged the light back in and turned it on, the offending signal returned.

The new problem.

I had several Fair-Rite Mix 31 snap-on ferrites, so I installed them on the power cord near the wall wart and  where the cord connected to the light. This made only a very small difference. The LED light's wall wart was plugged into a power bar, so I also added ferrites to the power bar's 120-volt power cord. Again, there was little improvement.

Next, I dug out my trusty battery-powered Eton radio and tuned it to a quiet spot on the AM broadcast band. Extending the antenna, I began hunting for the source of the RFI. When I moved the antenna close to the LED light's wall wart, the radio burst into noise. 

I considered trying a different power supply, but the LED light required 24 volts DC and all the spare adapters I had were 12 volts. After doing some online research, I came across a Mean Well power supply that appeared to have excellent filtering specifications. I ordered the correct model from Mouser Canada and hoped it would solve the problem.

Offending wall wart.

A few days later, it arrived. I plugged it in and—wow—the offending noise was completely gone. I placed the AM radio right beside the new Mean Well adapter and found it to be very quiet. It was satisfying to track down the source of the interference and solve the problem.

The lesson learned was simple: not all power supplies are created equal. In this case, the inexpensive wall wart supplied with the LED light was generating significant RF noise, while the replacement Mean Well supply was virtually silent on the air.

40m back to normal

The new Mean Well

This CQ WW WPX contest was my first major contest in a few years, as we are usually away on vacation and I end up missing it.

This year, my best bands were 20m during the daytime and early evening, before moving over to 40m later in the evening. Overall, the early evening and nighttime hours seemed to be the most productive, with both 20m and 40m really opening up.

During the daytime, I just could not get a good run going. At times, it felt like I was simply calling “CQ Contest” into the ether with very little response. Because of that, this contest turned into mostly search-and-pounce for me, with only the occasional attempt at running.

Throughout the daytime hours, I kept VFO A on 20m and VFO B on either 15m or, at times, 10m, constantly watching for openings. When conditions looked promising, I would jump down to those bands and was able to pick up additional contacts on 15m and 10m. Most of my 10m contacts ended up being with South America.

One thing that definitely kept me in the radio chair was the weather. It was quite chilly here, with daytime highs reaching only 8°C and evening temperatures dropping to around 2°C. In fact, I even had to break out the portable heater I use to keep my hands warm. I find that when my hands get cold, they just do not work as well on the keyboard when entering call signs and serial numbers.

This was also the first major contest for my new Icom 7610, and I am happy to say it performed flawlessly throughout the event. 

 I have been running my WSPR desktop unit for almost 24 hours to get a better feel for band conditions ahead of this weekend’s CQ WW WPX contest. The bands I focused on were 10m, 15m, 20m, and 40m, using my Hustler 4BTV antenna. The results showed that 40m and 20m have been the strongest bands, while 15m has been relatively weak and 10m has been virtually non-existent. The evening hours appear to be when band activity really picks up and could provide my best opportunity for strong run rates. We’ll see how it all plays out, because before you know it, Sunday evening will be here and another contest will be in the books.

OHB ver 4.23

 I have been sitting back and watching the many Hamclock projects evolve. What I was looking for was a project that, when finished, resembled Elwood's Hamclock. I am happy to report that I have settled on using OHB or Open Hamclock Backend. This has a very polished look and looks and operates, in my humble opinion, the closest to Elwood's Hamclock. It is a group effort and has progressed at a smooth pace. There is an OHB web page that offers support and status updates. I operate HamClock on my Pi4B, and if you operate Elwood's HamClock on a Pi, below is the process you go through to move from Elwood's version 4.22 HamClock to OHB version 4.23 HamClock. 

This script will download the script that you are going to need when entering the script listed below. As a side note, with some Pi OS's like Trixie, you will be prompted to enter your password whenever a "sudo" command is used. Just be aware that your password may be needed.  

 

4. The next command is: 

sudo fix-hosts

 I have read that you only need to enter if you are running Trixie or newer. In my case, I entered it anyway, as the instructions indicate you can if you would like to. I just did it as a just-in-case. 

5. After the above command has been entered, you may or may not be asked to reboot. I was not, but again I did anyway just to make sure. So I entered this command: 

sudo reboot now

 And it reboots the Pi, and if your HamClock starts up and is on the desktop, you need to again click on the lock and exit HamClock. 

6. You are now able to move over to either OHB, or you can also move to Hamclock.com backend. I will just be dealing with OHB in this post, but I will give you the command script for Hamclock.com backend as well. For moving to OHB enter this command: 

sudo ohb

If you want to move to Hamclock.com backend, then enter this script: 

sudo hcdc

7. Once you have done this, you can confirm that you have actually moved by entering this script: 

what

And it will confirm that you have moved to either OHB or HCDC, which over sudo command you entered above. In my case, the return script was: 

Your HamClock is set to Open HamClock Backend

   This confirmed to me that I had moved to OHB. 

 

8. The final step is to restart by entering this script: 

sudo reboot now

And once you have rebooted and HamClock goes through its startup, you will be asked if you want to go from version 4.22 to 4.23 and click YES.  

Updating

As a way of 2 side notes:

1. I did have to, for reasons not known to me, do the above process twice, as when I rebooted into the new feed for HamClock, I was not asked if I wanted to upgrade to 4.23. For some reason, it stayed on 4.22. Once I did steps 1-8 again, I was then asked to upgrade to 4.23.  

Ver 4.22 poor quality compared to 4.23

2. If you are operating Elwood's version of HamClock while it is loading, you will be asked if you want to upgrade to version 4.23, but as you say YES, you will be greeted with the following error message. To fix this, you need to change your back end. This is done by following the above 8 steps.