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.

Welcome to The Communicator

Welcome to the July-August 2026 issue of The Communicator. As summer hits its peak, this bumper edition is packed with the perfect blend of technical innovation, operating field reports, and rich radio history to keep you company during those long, warm evenings.

Inside, we dive straight into our summer operations with a full wrap-up and twin perspectives on Field Day 2026 and the RAC Canada Day contest. On the technical bench, we feature some incredible homebrew projects, including a deep dive into building an NTP Dual Clock (plus an intriguing alternative design), a True RMS to DC Converter for your DVM, antenna ideas from John VA3KOT and an Arduino NANO automation mod for the Yaesu FH-2. If you are looking to experiment, check out our pieces on reviving Teletext, expanded bandwidth with eSSB, automated FT8 with MSHV, or tracking the Pico balloon VE7NFR-15.

For history buffs, we explore the legacy of SSB pioneer Nicolaas Kooman and unpack the mystery of the secret Lagercrantz suitcase radio. Top it off with crucial operating advice—like how to avoid bricking your Quansheng UV-K5— Amateur Radio Goes Hollywood, and a classic club Taco Salad recipe, and there is something here for every shack.

So power up, tune in, and turn the page—The Communicator has something for every communicator, now reaching 165+ countries.

73, and enjoy the read!

Download the Lower Resolution Issue - 7 Mb

Read it On-line as a Magazine

Please note that there are active links for additional content when viewed on your device.

~ John VE7TI, Editor

Contents for this issue: 

There I was, minding my own business at Field Day, when I ended up in a conversation with The Matts (KF0RIG and KG0AT). They said something about being in the Brass Knuckle Gang, which I knew nothing about. One of the Matts said “it is kind of fun and kind of dumb.” I thought “this ... Read more

The post K0NR BKG114 appeared first on Above Average Terrain.

Show Notes

Featured Topic

• OscarWatch by Peter Goodhall (MM9SQL)
  • Source: https://lhs.fyi/LM (github)
  • GPredict: https://lhs.fyi/LR
  • SkyRoof: https://lhs.fyi/LS (The SDR Satellite Tracker I couldn’t remember)

Announcements & Feedback:

• Announcements:
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  • We need your feedback!
    • Comments, Questions, Show Topic Ideas! Email us at [email protected]
  • Memorial Service for Russ, K5TUX
    • There will be a memorial service held for Russ at our home in Mt. Vernon, Missouri on November 1, 2026.  Everyone is welcome!  If you’d like to join us, please send an email to [email protected] and we’ll send you more info!
    • Facebook event page: https://lhs.fyi/mem
• Feedback:
  • YouTube Comment on Episode 620 from @TurtleWaxed
    • Thanks! I didnt know about meshyface..will have to check it out. LHS rocks! :)

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• Live Show Participants
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In this episode, we join Martin Butler M1MRB, Chris Howard (M0TCH), Martin Rothwell (M0SGL), Frank Howell (K4FMH), Bill Barnes (WC3B) and Leslie Butterfields (G0CIB) to discuss the latest Amateur / Ham Radio news. Colin Butler (M6BOY) rounds up the news in brief, and the episode's feature is Windows 10 to Linux

We would like to thank Philip Heckingbottom (VK6ADF) and our and monthly and annual subscription donors for keeping the podcast advert free. To donate, please visit - http://www.icqpodcast.com/donate

• Volunteers Wanted for Intruder Watch team
• Young Ham Radio Operator Supports the America250 Celebration
• Tour De France is a Tour De Callsigns
• Radio Has a "Senior Moment" to Remember
• New Annual Verification Process by RadioID.net
• 2026 AMSAT Space Symposium & Annual General Meeting
• New Technician Question Pool Takes Effect 1st July 2026
• WRTC 2026 Update

In this episode, we join Martin Butler M1MRB, Chris Howard (M0TCH), Martin Rothwell (M0SGL), Frank Howell (K4FMH), Bill Barnes (WC3B) and Leslie Butterfields (G0CIB) to discuss the latest Amateur / Ham Radio news. Colin Butler (M6BOY) rounds up the news in brief, and the episode's feature is Windows 10 to Linux

We would like to thank Philip Heckingbottom (VK6ADF) and our and monthly and annual subscription donors for keeping the podcast advert free. To donate, please visit - http://www.icqpodcast.com/donate

• Volunteers Wanted for Intruder Watch team

• Young Ham Radio Operator Supports the America250 Celebration

• Tour De France is a Tour De Callsigns

• Radio Has a "Senior Moment" to Remember

• New Annual Verification Process by RadioID.net

• 2026 AMSAT Space Symposium & Annual General Meeting

• New Technician Question Pool Takes Effect 1st July 2026

• WRTC 2026 Update