Ground is a Myth! | 2024 ARRL National Convention

Presented by: Kristen McIntyre, K6WX, ARRL First Vice President

Ground is something you stand on, but in an electrical sense, the meaning is much less clear. When it comes to hams and ground, things get really confused. We drive rods into the earth, but why? Let's take a look at whether any of this makes sense, and what theory tells us about "ground,” and if it exists in any sensible way at all. We’ll talk about DC grounds, RF grounds, and even about gravity.

#amateurradio #hamradio #electricalengineering #ground #radio #arrl #daytonhamvention #hamvention

[everettputerbaugh]

As I was attending warranty training, we all noticed the heat sink (fin) at chassis ground next to the popular test point (pin) that was at 130v above earth ground. It kept us awake as the class progressed. That was a practical demonstration that "ground" is a relative term.

[brunonikodemski]

This is a super-good presentation, and hopefully will be assimilated by all of the attendees at the convention. I lived through almost all of the problems and content of this video. As an EMC/EMI and Lightning engineer, it was obvious that there are "many grounds" within any larger system, particularly where larger powers are transmitted. Ground loops, Ground bounce, Electrical or Radiative leakage, Adjacent coupling (even through iron pipes), all occur. Formulas for these are available in any college textbook. Locally, there are no universal grounds, including lightning. Just look at the sites where people died, when entrenched or climbing into gullies in the mountains, where the strokes/strikes just go down the creek bed, near or through them. If you want a good ground near a beach, find a place where a bolt hit the sand, and dig around it. You will find a glassified wormlike area going many feet deep, and these are often filled with molten lead or solder, and sold as objects of art. That lightning strike (probably the only one of several) has managed to find its "own" ground. Hits on vehicles often go through all of the tires, and flatten one or all. RF burns can occur along any conductor where a resonant structure/length occurs. This often happens along long coils (like a Tesla coil), where the local lateral or angular resonances amplify the stray radiated fields. Seen these things many times, and there are videos on the Inet which show these various EM effects.

[davidpacholok]

Kristen thanks for a great presentation overall. Many of us have multiple antennas on multiple poles with a separate ground rod for each. I keep harping about the importance of bonding ALL GROUND RODS TOGETHER OUTDOORS, AND TO THE UTILITY GROUND AS CLOSE TO THE SERVICE ENTRANCE AS POSSIBLE.
If LIGHTNING strikes an average 30KA bolt multiplied by a NEC specified ground resistance of 5 ohms or better yields 150 KV ground bounce for the struck antenna/pole. The other ground rods on other antennas/poles will show much less voltage, depending upon the distance from the one Struck. This can bring 150KV into your shack on one feed line. Not good. If you bond ALL grounds including together with heavy copper cable, all your feedlines and your entire home will bounce to as much as 150KV but the Differential Voltage between all feed coax and connected equipment should be only a very few KV, .and unlikely to set your shack or home on fire.
David ac9cx
Power electronics engineer for 5 decades, now retired.

[NIA-]

Great info here! I can't tell you how many times I've been called crazy, dangerous, and uninformed when explaining to them why grounding is not the panacea they think it is. A lot of this comes from past practices with old tube rigs without a ground wire connected to the mains. Equipment manufacturers still put these ground lugs on the back of their gear, implying that one has to connect them to ground. But that is no longer the case, because the third wire is now included on all gear. Thanks Kristen!

[scotty]

I almost blew this off because of the title, but I'm glad I watched it. It was very informative and Ms. MacIntyre was a good speaker. Well done!

[wvpkf]

In the "Split Phase and Neutral' slide [there are no slide numbers] European houses are not fed 240-0-240 in the way shown. Houses in USA are fed 120-0-120. Europeans are single 240 VAC. That's why there aren't transformers on poles for every three houses all over the place like there is in the USA. A much larger transformer is located locally and ground mounted (they are too massive to put on wooden poles). The phases are balanced at that point by assigning an equal load of houses so that one side of the transformer is not loaded more than the other. It also provides the ability for commercial users to pick up 3 phase at 415 VAC with little difficulty. The systems are quite different.

[GREGGRCO]

Excellent Excellent Excellent presentation ! Absolutely enjoyed her presentation ! Thank You !!!

[lifegettingintheway]

22:24 "The best we can do is differentially stabilize at certain points". I propose we call those points "ground" because we need a simple name that suggests a purpose. We can then document the purpose of those points and how they are used in practice. The universe of grounds is so vast it defies calling them a myth. In use they are a reference point for something and in practical circuits that is generally self-identified in the diagram. In practical terms I would use the "ground" in my electrical panel to measure circuitry in my house. I would not, except for curiosity, use my ground to measure circuits in a neighboring house. That is not a practical circuit.

[sporsterini]

This explains why some things worked for me at a certain QH and not work at others. I learned by trial and error working out of apartments as well as homes. This pretty well sums up what grounds are all about. Great presentation Kristen.

[davecasler]

Kristen, I enjoyed your presentation. I answer lots of questions about grounding for "Ask Dave." This has not changed any information in my head, but has sure changed my perspective. Thanks for taking this back to basics. 73 de KE0OG

[-Mark_F]

Very nice presentation. Almost like a relief in a way because the subject of ground is not an easy thing to understand and sometimes even contradictory. Thank you for explaining that the theory of ground has many facets to it and it can be many different things to many different people and many different situations.

[rb]

Wow! Finally someone who actually understands. So many people don’t understand.

[MartinHuml]

Thanks so much Kristen for the interesting presentation! She describes and explains the issues around grounding in our hobby very nicely and clearly. Martin OL5Y

[WheezyE]

Incredible presentation. I learned a ton from this. Thank you!

[garypoplin]

2:00 - Wow! This is one of the few times since school that I heard a talk using the term ‘podium’ correctly! You stand on a podium to give a lecture behind a lecturn.

[arekx]

It was mentioned that connecting ground connector on equipment chassis to outside rods can "invite" lightning to inside. Won't coax shield itself invite lightning anyway? (lightning antenna -> coax shield -> radio -> electrical ground -> electrical rods outside house/at transformer station - as a path)

[maxmn]

Thank you for this very nicely presented refresher!
For understanding things, a historical perspective can be very helpful. I‘d like to recommend KathyLovesPhysics videos (and book); lightning is covered, too.

[sugarpuddin]

I'm a physician of internal medicine. And taught biochemistry to medical students

We have same problem in medicine: many, many words are misused; definitions are wrong or change depending on author; and no one bothers to understand what is actually happening. People simply settle on contrasting and inconsistent definitions...

[ham-radio]

Hi Kirsten, Respectfully, I strongly disagree with the title of this presentation. I honestly believe it to be dangerous. It is 0200 local and hopefully I can make my disagreement with you clear to others. There is a ground. You must ground. Ground is not a myth. Ground is a requirement in all jurisdictions. Many use the National Electric Code. We in California have a more restrictive State electrical code. Outlets must be grounded. A driven rod outside of the station location in many, if not most situations is a violation and just plain dangerous. ALL current must flow back to the ground at the main panel. There are some exceptions. As a former Deputy Building Inspector, I want all current to flow back to the panel's ground and not a driven rod somewhere in the event of a fault. Why the ARRL is teaching with the title that Ground is a Myth is in my view irresponsible and dangerous. Respectfully, Jim Heath W6LG YouTube Elmer and licensed for more than 60 years and an ARRL Life Member with many ARRL awards. Please excuse typos as I am taking strong chemotherapy at this time.

[dougbarry]

Great presentation, thank you for sharing.