For the past 30 years I have lived-in the highest point for 25 miles in any direction. I have three towers, 70 feet, 150 feet, and, until two years ago, 200 feet. I lowered the 200 foot tower to 155 feet two years ago. For the first 15 years my equipment was struck and damaged 4 times for a total of $15000 dollars in damage. This inspite of the fact that everything was grounded. I'm sure something wasn't right with the grounding systems, or this wouldn't have happened. After one strike, the drawers were welded shut on the metal desk the equipment was sitting on.
At that point, 15 years ago, I built all wooden tables to sit the equipment on and started a policy of disconnecting everything that went to the outside world. I made a written checklist and followed it faithfully every time it clouded up or I had to leave the equipment for more than a few hours. I reconfigured the AC to the equipment to be fed by one circuit. I don't run an amplifier so the power load was less than 500 watts, I am sure. The AC supply for the gear comes from the inverter, a pure sine wave circuit and a 100 amp hour AGM battery. That inverter goes to the only source of AC. All computers are also powered from the same system. So when I disconnect, one AC plug removes everything from AC source. THEN I also disconnect the phone line to the house at the outside customer access box. AND I disconnect the station ground which goes through the largest power pole connector available. Now the equipment is bonded together and isolated from ground. All cables are disconnected and removed from the vicinity by several inches (a weak point, I know). Since implementing this system fifteen years ago, I have had zero lightning damage, even though I have seen direct strikes to the towers. I spent ten years of my EE design career designing lightning suppression circuits. The bottom line is, you can't prevent damage if things are connected to the outside world. I won't even sit in the same room with the gear when lightning is about. During one of the strikes, I had a turned wooden lamp sitting on the top shelf of my rig setup. I forgot to unplug it. Lightning got it and it exploded, creating 15 inch long splinters out of the lamp body. One buried itself in the wall, leaving a one inch diameter hole, which I have left as a reminder. Several other splinters flew 12 feet across the room (right through the space where I would have been sitting in my chair) and buried themselves in the back of a small couch where my wife usually sits and reads in the evenings. At the time, we were out of town. When I returned and found the scene, my first thought was that someone had broken in and trashed the place. Bottom line --- disconnect power, telephone line, ground bus, and all cables every time, no exceptions. PS-- my Mac Mini does not have a way to attach a ground wire unless I want to drill and tap a hole in the aluminum case for a ground screw. End of soapbox... 73, Dave, K4TO On Tue, Oct 30, 2018 at 6:36 AM <w5...@comcast.net> wrote: > very good suggestions Wayne. I work in the Communications field and have > for > 40 years. I have seen massive amounts of lightning damage, regardless of > grounding , protection, etc etc. If you take a direct hit.. something is > going to fry and that’s it. > > I unplug antennas, power cords AND Ethernet Cables to all computers in my > ham shack. I must confess however, I have not disconnected the USB and > RS232 > lines. I sort of figure if the power cord and ethernet cables to my > computer > are disconnected, the path for the power surge is eliminated. BUT.. guess > it > would be better to be sure. And btw, yes my computers are all grounded > very > well. > > thanks for the heads up > > Ronnie W5SUM > > > -----Original Message----- > From: Wayne Burdick > Sent: Monday, October 29, 2018 10:08 PM > To: Elecraft Reflector > Cc: k...@yahoogroups.com > Subject: [Elecraft] Avoiding costly lightning damage to your radios gear > > Every year, especially in summer, our techs see radios come in that have > been damaged by lightning, despite the radio's protective circuitry. You > can > take steps to reduce your own risk. > > 1. Many of us remember to disconnect antennas when lightning is > anticipated. > But in our experience, the most common source of damage, by far, is from > an > attached computer. Computers themselves often fail due to lightning > strikes. > They can also act as conduits for surges to other gear. Just to emphasize > this point: Customers often say "I disconnected everything but the USB > cable > to the computer...," which left the interface to their radio exposed. > > Note: Only in rare cases have we seen surge damage via other I/O ports > (accessory jack, paddle/keyer jacks, PTT IN, KEY OUT, and DC). USB and > RS232 > ports are the most susceptible. > > 2. Some stations have an ad-hoc ground system and little or no ESD or > surge > protection. If you haven't already taken protective measures, we strongly > recommend reading this article, which goes into some detail regarding how > lightning finds its way in: > > > http://www.arrl.org/files/file/QST/This%20Month%20in%20QST/June2017/Chusid-Morgan.pdf > > At the very least, be sure your PC and other gear share a short, heavy, > common ground. > > 3. As for protecting your PC, here's a good starting point: > > https://www.wikihow.com/Protect-a-PC-in-a-Thunderstorm > > 73, > Wayne > N6KR > > > > > ______________________________________________________________ > 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 w5...@comcast.net > > ______________________________________________________________ > 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 k...@arrl.net ______________________________________________________________ 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
