These kinds of questions are exactly why there is an entire ARRL book on the subject.
Short version, you need a system that provides both a safety ground for the AC power wiring and an RF ground for lightning protection. In 2020, both the CZU Lightning Complex and SCU Lightning Complex fires were large destructive fires started by lightning. My weather station counts lightning strikes near Palo Alto. It recorded 27 in Jan, 17 in Feb, and 16 in March. That would be one thunderstorm in Texas, but it is still enough to damage a radio. wunder K6WRU Walter Underwood CM87wj http://observer.wunderwood.org/ (my blog) > On Jul 31, 2023, at 2:14 PM, jerry <je...@tr2.com> wrote: > > Interesting. Suppose the service entrance is at one end of the house, > and the ham shack at the other end? I don't think it's physically > possible to provide a low inductance path that's 60 feet long, is it? > > Would a solution be to DC-isolate the station from the grounded antenna? > Say with a wideband toroid 1:1 transformer? Then ground the station through > the > 3rd pin of the AC outlet? > > Here in the San Francisco Bay Area, lighting is rare. It used to be > entirely > unheard of - we just don't get the kind of convective weather that produces > it. We're more about coastal stratus. But with climate change, that might be > changing. There was quite a display once last year. > > - Jerry, KF6VB > > > On 2023-07-31 13:20, Fred Jensen wrote: >> Be very careful of advice regarding lightning protection. There are >> some very good sources, starting with the NEC and including material >> from ARRL. Some is somewhat non-intuitive. For example, the NEC >> requires that any additional "earth electrodes" [aka ground rods] be >> bonded to the service entrance earth electrode with a low inductance >> path. There's been quite an array of advice circulating here recently, >> much of it wrong, some dangerous. >> 73, >> Fred ["Skip"] K6DGW >> Sparks NV DM09dn >> Washoe County >> Geoffrey Feldman wrote on 7/28/2023 5:02 PM: >>> First thing and foremost - switches are mostly not relevant to protection. >>> Energy that can travel 1000' through the sky is likely to continue across >>> most switches. So, the utmost of safety is what you indicated you did - >>> disconnect. By disconnect, I mean either disconnect outside the building, >>> leaving the feed on the ground or leave the feed connected to a copper plate >>> that is in turn connected to an 8' deep ground stake. On the inside of the >>> house, disconnect the lines from that plate and leave them on the floor. >>> Another such stake near the feed point of the antenna is also a great idea. >>> If it's possible to lower the antenna when not in use, that's a great idea. >>> This should be the default when not in use. >>> You have the belief that no grounding system is perfectly effective (for >>> all >>> imaginable strikes) - maybe, but a good grounding system is far better than >>> foolishness. A grounding system, or an antenna is not a "lightning >>> magnet". If it doesn't strike it won't. If it does it will and the grounding >>> system assures the energy will be less likely to cause harm. Some places and >>> circumstances are more or less likely but everywhere is possible. If that >>> possibility happens, a good grounding system is why it is likely to be >>> survived. >>> A key thing to understand is that when Lightning strikes in nature, all the >>> energy travels along the surface of the ground. It can do this for many >>> feet and be lethal doing it. Anything that stands along the radius from the >>> point of the strike (one part closer and the other further) is in danger. >>> Four legged animals, having more distant contact points, more dangerous. >>> The purpose of a ground stake (8' straight down) is to channel the >>> electricity deep, rather than along the surface. >>> Don't use emotional theories. Read the lightning mitigation and grounding >>> books offered by the ARRL. Use UL approved conductors and stakes. Do not >>> use your homes electrical service ground stake. Keep that separate. >>> All the above is a "cliffs notes" and so is anything else posted here. Read >>> the books. Ask senior members of a local club, to review your plan. >>> W1GCF Geoff > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Elecraft@mailman.qth.net > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to wun...@wunderwood.org ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:Elecraft@mailman.qth.net This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html Message delivered to arch...@mail-archive.com
