Discussion regarding lighting protection and the possibility of the tower base exploding after a direct lightning hit. Compiled from the CQ-CONTEST reflector by KA9FOX ***************************************************************** I guess I'm an expert since I've witnessed a direct lightning strike first hand. A couple of years ago, I was at K2ZJ working some DX on whatever band it was. The static was getting pretty loud and I asked John, "you think I should shut everything off ?" Yes, was the reply, and all equipment went off and coaxes to ground. Both of us sitting pretty close to the equipment. About 90 seconds later the lightning hit the taller (90 foot) tower. We witnessed a big flash and deafening boom ! It was increadibly loud. Puts any fireworks I've seen to shame for shear dB of loudness. My left ear was deafened from the blast, you know, like after going to a loud concert. My son who was visiting John's son wanted to go home, and for several months did not want to go back, even on sunny days ! The strike came in through the switch box and rotor cables. There was a black mark on both sides of each box; from switch box to rotor control box to rig to rotor control box to 2nd rig to amplifier, with maybe a power supply in there somewhere. You get the idea. The lightning hopped from box to box leaving a black char mark on each side. 1 rotor control box started to smoke, I started to laugh, and John got mad ! :-) You had to see it. It was kinda funny. Face plate from 1 rotor control box went flying by my head, missed. Minor damage to amplifiers. Switch box relays in bad shape. Maybe 5 hundred dollars damage. Lucky it was that low. Oh yeah I think a power meter went up in smoke too. The insides of the worst boxes looked like everything exploded. Picture an electrolytic pealed back like a banana ! Remnants of ICs consisted only of the pins. The pot in one of the rotor boxes looked like an exploded view you would see in the manual, kind of disassembled itself. Both radios undamaged, a blown diode in 1 amlifier. A rotor pot, amplifier relays and both radios have stopped working since. Maybe after affects of the lightning. Also minor damage to the ceiling tiles. You could see black marks on the tiles everywhere there was a joint in the frame. Some smoke but no fire. The ground straps at the tower base were gone, as well as the clamps. They have not been seen since. The base itself was fine, no exploded base or concrete. Grounding is through ground rods external to the base, with wide straps from the tower legs to the ground rods. So a long story to get to the point: I think you have more important things to worry about than the base of your contest :-) tower exploding. Seems like other stuff is more likely to be damaged than the tower. 73 Scott WA2LCC sjb@rfc.comm.harris.com ------------------------------------------------------------------------------ Hi! We are planning to set up a contest-QTH with several rock mounted towers. Has anyone information how to protect a rock mounted tower from lightning. Allmost all litterature is about putting down a waterpipe at the side of the base about 6ft or so and connecting a wire from tower to the pipe. But what to do do when the tower is mounted on solid rock? If any ideas please mail me directly! 73 de SM0AJV/Ingo Ingemar Fogelberg if@cec.comm.se ------------------------------------------------------------------------------ Specific information on this very topic is contained within the publications of: POLYPHASER CORPORATION PO BOX 9000 2225 PARK PLACE MINDEN, NV 89423-9000 Given that I have had much Email returned from overseas as undeliverable, I am placing this on the CONTEST reflector, as well as sending it directly to you... Denny k8do@aol.com ------------------------------------------------------------------------------ Speaking of lightning protection, two of us each ordered some stuff from ICE almost 4 weeks ago and still haven't seen either order. They've got our money and now the response is "I'm in another building so I'll have to take your number and call you back", or "the lights are out in that area, so I'll have to take your number...". We're getting pretty suspicious and the contest/dx antenna growing season is going by quickly. Is this kind of customer "service" typical of ICE? Bill Standerfer, KF0DJ bills@lvld.hp.com ------------------------------------------------------------------------------ On Tue, 20 Jun 1995 13:58:49 -0600, "Bill Standerfer" KF0DJ wrote: > Is this kind of customer "service" typical of ICE? K1VR: Not in my experience. They've been better than good to me. k1vr@k1vr.jjm.com ------------------------------------------------------------------------------ You do wait for their stuff but it's high quality and several of their products are not available to hams from other sources. Ordered once-will order again. Dan Kovatch, W8CAR pems_st_dk@noeca.ohio.gov ------------------------------------------------------------------------------ Yesterday I wrote: > Speaking of lightning protection, two of us each ordered some stuff from ICE >almost 4 weeks ago and still haven't seen either order. They've got our money >[...] I've had several responses so far and the majority say that this is normal from ICE. A couple reported that they were satisfied. One said it took 6 months to get something from the catalog. I'd cancel the order, but they seem to be the best in the business for this kind of equipment. Too bad they've got us over a barrel. They might get the point if folks started taking their business elsewhere. I really hate giving my money to people like this. Bill Standerfer, KF0DJ bills@lvld.hp.com ------------------------------------------------------------------------------ Bill: That's pretty typical. They do eventually ship and the stuff is as advertized. What can you do? Well, a number of dealers around the country stock the most popular ICE devices, so give them a try the next time. I suppose you can ask ICE not to charge your credit card until they ship, but they've ignored this request from me every time. If I get the credit bill without having received the equipment I've ordered, I contest it with the credit card issuer. This usally resulted in receiving the shipment within a few days. I think they just have too much business...their equipment is very nice and not overly expensive, but that they only manufacture a few items in bulk at a time. Maybe someone in Indianapolis has visited their operation and can tell us what gives. Don't give up hope!! 73, Jim W9WU JimW9WU@aol.com ------------------------------------------------------------------------------ Sorry. After all the traffic on lightning I thought I would put in my two-penny worth...... Personally, I have never been pursuaded by the argument that you should ground ANYTHING for lightning protection. Why attach a nice healthy fat ground to a tower to ATTRACT the lightning? This isn't lightning protection - this is lightning ATTRACTION! See the case of the guy who had his tower hit every time a storm came by..... saving his nieghbours from being hit!!!!!!!!! For this reason, I consider anybody who spends time and money on all this PolyPhaser garbage as wasting their time and money.... completely! As for the base exploding stuff ..... well, most of the towers in the USA are healthily guyed (you see very few free standing). With a guyed tower, it's not (or shouldn't be) the BASE that's keeping the thing up! The only cracks I've seen in a tower base was when the concrete dries too quickly in the Sun..... Finally. Taking a leaf out of the sailing book..... The same crazy situation exists there. One argument goes that lightning will hit the mast and if the rigging isn't connected through to a hull plate, a hole will be blown in the bottom of the boat as the bolt tries to reach the sea..... Again, like the exploding base, NO ONE EVERY SEEMS TO BE ABLE TO SUBSTANTIATE THIS MYTH..... From the manual supplied with all boats made by Catalina Yachts: The merits of grounding the rigging system and ground bonding are controversial. Many different configurations may exist. As the merits of this method have not be substantiated Catalina Yachts manufactures the hull without bonding. The owner is responsible for fitting ground bonding and any consequences of so doing..... or words to that effect. IN OTHER WORDS .... we don't do it because it's not necessary and if you do do it then whatever happens is YOUR fault (if you attract lightning to your boat and you're hit, you're responsible!). I have been at sea with a non-bonded boat (not mine) and lightning was pitching into the sea EVERYWHERE around us. I still maintain that we did not get hit in seemingly 100% chances because we weren't waving a 50' high lightning conductor around!!!!!!!!! When a lightning bolt lands feet away from you several times in the space of minutes and you have a 50' metal mast in the air and you don't get hit, I think that proves the point....... Paul Evans, W4/G4BKI paul@paccomm.com ------------------------------------------------------------------------------ Pa> Personally, I have never been pursuaded by the argument that you Pa> should ground ANYTHING for lightning protection. Why attach a nice Pa> healthy fat ground to a tower to ATTRACT the lightning? This Pa> isn't lightning protection - this is lightning ATTRACTION! Pa> See the case of the guy who had his tower hit every time a storm Pa> came by..... saving his nieghbours from being hit!!!!!!!!! Pa> For this reason, I consider anybody who spends time and money Pa> on all this PolyPhaser garbage as wasting their time and money.... Pa> completely! A coworker recently had his new house struck, setting the roof on fire and destroying the second story. He was not a ham and had no towers, trees, or other means of "attracting" lightning. What is the probability of his house being struck versus one of his neighbors? Or a neighboring ham? I presume it is very low and he was simply unlucky. BUT - I feel very confident in stating that IF he had a properly grounded tower/lightning rod next to his house (and Josylns in his service panel), he would still have a roof! After a recent conversation with my agent, I discovered that I'm eligible for a LIGHTNING ROD DISCOUNT on my homeowners insurance! I currently have a 120'(soon to be 140') tower (with lightning rod) near my house that has been struck previously with NO damage. Several of my neighbors, on the other hand, have had TV antennas and trees struck and HAVE suffered damage. Since installing Josyln protectors in the service panel, and ICE protectors on the coax, several storms have damaged appliances and electronics in the neighborhood, but not in my house. I'll keep my ground rods, thank you. Pa> As for the base exploding stuff ..... well, most of the towers in Pa> the USA are healthily guyed (you see very few free standing). Pa> With a guyed tower, it's not (or shouldn't be) the BASE that's keeping Pa> the thing up! Pa> _ _ _ _ _ Pa> Paul Evans, W4/G4BKI paul@paccomm.com +1 (813) 874-2980 I'm not very concerned about the possibility that the base of my guyed tower may explode since the base could be omitted and the tower would still stay up! The concrete anchors are a different story however, and I don't care to find out if they can explode. Each one is connected to an 8' ground rod tied radially to the ground field (3 rods, radials, and screen) at the base of the tower. 73 Bill N6CQ/3 (n6cq@paonline.com) ------------------------------------------------------------------------------ >Personally, I have never been pursuaded by the argument that you >should ground ANYTHING for lightning protection. Why attach a nice >healthy fat ground to a tower to ATTRACT the lightning? This i>sn't lightning protection - this is lightning ATTRACTION! The reason for grounding the tower is not to ATTRACT, but to cause a discharge of the potential that is induced by certain storm conditions - BEFORE it reaches breakdown potential and creates what is call LIGHTNING. It has been observed to work on my own installation. Arcs occur going UP from the tower to the clouds. Thus, the potential never becomes great enough to breakdown causing a lightning bolt. I spent some time professionally on development of a transportable metal complex which contained sensitive electronic equipment. Lightning was a big issue and a significant system requirement from the Customer's point of view. The several experts engaged by the customer all had some variations in their detailed views, but the consensus was that the ground system and lightning rods were the proper approach for the reasons described above. If you look at the large number of broadcast towers, and other objects, you will note that they generally are protected with well-grounded lightning rod systems. Rarely do they take a hit.... that verifies the theory from my point of view. Ron Klein - W0OSK ronklein@ix.netcom.com ------------------------------------------------------------------------------ Bi> Speaking of lightning protection, two of us each ordered some stuff Bi> from ICE almost 4 weeks ago and still haven't seen either order. Bi> They've got our money Bi> and now the response is "I'm in another building so I'll have to take Bi> your number and call you back", or "the lights are out in that area, so Bi> I'll have to Bi> take your number...". Next time order from Radioware (508-452-5555), a stocking distributor for ICE. Their prices are a little cheaper than the factory price too! I'm surprised that ICE didn't refer you to Radioware - that's how I discovered them. 73 Bill N6CQ/3 bill.lumnitzer@paonline.com ------------------------------------------------------------------------------ While it is correct to say that the concrete base of a tower does contribute to the overall ground for the tower, it is important to remember that the real purpose of the concrete base is to support the tower! Anything that compromises the ability of the base to do its primary function represents the potential for the entire tower to fail. The average lightning stroke has a peak current on the order of 40,000 amps. A direct hit on a tower that is only grounded through the concrete base results all of the current flowing through the base. Concrete, even after it has cured, contains some water. The ligntning strike passing through the concrete can cause this water to turn to steam. As the water expands it can cause cracks in the concrete. Worst case the concrete will "explode" much like a tree will during a direct hit. However, even if the concrete doesn't explode, the damage done by the lightning strike could significantly weaken the base and in turn its ability to support the tower. For this reason separate ground rods (or other grounding techniques) should be used to shunt the lightning energy around the concrete base. Mike Zeug K9EC Michael.Zeug@ameritech.com ------------------------------------------------------------------------------ Frank, W3LPL, wrote: >Mike, > >I'm sure the readers of this newsgroup would appreciate it if u >could provide evidence and details of damage sustained by tower >foundations as a result of a lightning strike. Thanx! > >73!FrankW3LPL Frank, et al: I have no first hand evidence, all of my towers are properly grounded with ground rods external to the tower base. However I can provide the following technical reference: "Telecommunications Electrical Protection" by Edward P. Carter Copyright 1985 AT&T Technologies, Inc. I quote from chapter 9.5, "The antenna structure is a prime target for lightning, and although metallic antenna horns and dishes are unlikely to be damaged by a direct stroke, the entire structure consitutes an excellent transmission path for conducting high current into the equipment building. Stroke current will also seek a path to ground via tower footings and guy anchors. At these points, explosive damage may occur unless alternate paths are provided to bypass the current and reduce voltage differences." The author goes on to say, "Towers should be grounded to reduce the amount of stroke current entering the station area and to prevent possible lightning damage to foundations and guy anchor footings." While this text is primarily aimed at the protection of commerial telecommunications facilities (including microware radio sites), I believe that it is relevent to ham radio installations. The bottom line is that the concrete base of the tower supports the entire weight of the tower PLUS the downward force exerted by the guy wires. Using the tower base as the ONLY ground for the tower may compromise the tower base's structural integrity resulting in a potentially dangerous situation. Likewise, not providing a separate path to ground at the guy anchor points may compromise the structural integrity of the guy anchor. I would hate to see anyone killed or seriously hurt because they didn't think it necessay to install a protective ground system for their tower. 73 de Mike K9EC Michael.Zeug@ameritech.com p.s. You may be able to order a copy of this text by calling the AT&T Customer Information Center on 1-800-432-6600. Ask for select code 350-060. ------------------------------------------------------------------------------ I live in Central Florida, which is an area known as the "Lightning Capital of the United States". We experience >100 days/year of lighting activity. Lightning bolts in Central Florida are THREE times more powerful than your "average" bolt, and also carry two to three times the current ofyour average, every day strike. Because of this, lightning protection is a subject on which I've done a fair amount of research. Having done this research (which, by the way, was neither difficult nor boring), I find it very difficult to deal with some of the ridiculous "theories" on lighting protection I've heard and seen. From the messages I've read - and I've just plowed through them all - there's been only a few excellent sugestions. One of them was to purchase the PolyPhaser book "The 'Grounds' for Lightning and EMP Protection", by Roger R. Block. Anyone interested in this topic - and that should be EVERYONE save a few of the West Coast USA types - should know the basic information (as opposed to the formulas, etc) in this book by memory! Think about it - is it REALLY a matter of "life and death" if you choose between an FT-1000 and an IC-775 for your next rig? No. You can't say the same thing about lightning protection! For all of the thousands of dollars many of us spend on radios, antennas, $1,300 Geochron clocks, Pentuim PCs, and other "essential" widgets, it's interesting to speculate why ANYONE would be willing to let twenty-five bucks get between them and continued ignorance on such an important subject. With respect to the "exploding base" myth, Mr. Block has the following to say: (he is discussing "Ufer" grounds): "One of the most important tests performed was under acutal lightning conditions. The test was to see if the Ufer ground would turn the water inside the concrete into steam and blow the foundation apart. Results indicated that if the Ufer wire were long (20-feet minimum) and kept approximately 3-inches from the bottom and sides of the concrete, no such problems would occur. (In my many years of experience, I have only seen one tower base with cracks that could be considered as lightning induced....)" With respect to the "Don't ground anything and lighting will not hit it" argument, Mr. Block says: "One of the best sayings is really not a myth at all "A gounded tower is more likely to be hit. As we say in the graph in chapter one, the taller an object the more frequently it's struck. Why ground a tower if it means that it is more apt to be hit? Look at it from the reverse point of view - if a tower that isn't grounded is hit, who would have control of the situation, the tower owner or Mother Nature? With a properly grounded tower, the owner has control. The whole concept of lightning protection is to control and direct the lightning surge energy so that it does the least amount of harm or damage." So, proper lighting protection is really a matter of CONTROL. Do you want to ALLOW yourself to be a victim, or do you, to the best of your ability, manage the situation to afford yourself the safest conditions possible? Clearly, the idea of NOT grounding your station seems a bit silly when cast in this light. NOTHING is a perfect insulator! Even a Fibreglas pole will conduct electricity if it's covered with rain water (witness the many VHF/UHF verticals blasted off the tops of towers every year), so pretending that an ungrounded tower will not be struck is sheer fantasy. Hopefully, the above quoted material didn't violate too many copyright laws. I would submit to you that that information ALONE is worth $25! Another tip is to make sure that all of your grounds are at the same potential, including your house ground. This means connecting ALL of your ground points together. I have four towers; three of them 100' or greater in height. They are the tallest things around for miles and miles. They ALL have ground radials with ground rods every 16', and all four towers' grounds are tied to a common grounding point just outside the shack (where the lightning arrestors are) and also to the house ground. I've used over 85 8' ground rods, and buried more ground wire than I even want to think about. It's the price you pay for not being a victim. Oh, does anyone want to know why those wire-brush thingies sold as "lightning protection" don't work? What about the "ground radial circle" myth? What's the significance of 150 feet with respect to lightning strikes? Get the book. 73,Steve KC2X Narcoosee, Florida ssacco@mcimail.com ------------------------------------------------------------------------------ There was an hour-long special on lightning on The Learning Channel yesterday evening (Science Frontiers). One of the segments dealt with a mountain-top lightning research facility in New Mexico. Apparently the place is situated amidst an area known for the frequency of its lightning strikes. Part of the work there is to test various styles of lightning rods, side-by-side. The on-camera staffer claimed that it was very unusual for lightning to strike _any_ of the tested lightning rods, despite their prominence. Go figure. Anyhow, it was an interesting program, especially in light of recent discussions here. Bill/NG3K wfeidt@cpcug.org ------------------------------------------------------------------------------ FWIW, there were two good articles on lightning protection in QST magazine - October and December 1994. In Minnesota, my 90 ft tower was stuck by lightning almost every time a cloud passed overhead. I estimate I was hit 4-5 times each summer. My neighbors were glad to have such a big lightning rod protecting their property. I never lost any equipment and don't think the cement exploded but it could have been damaged without my knowledge. Anyway, the tower had one copper pipe ground rod next to the cement base. I had good ground conductivity (unlike my present location - but my current QTH never has lightning!). I also switched all coaxes to ground and would usually disconnect the main breakers coming into the shack. gl &73, Bob Engberg, K0MVL engberg@ctis.af.mil ------------------------------------------------------------------------------ Let me start this humble missive with the comment that I truly believe that there exists in the vast genetic code a small microscopic protoplasmic mechanism that establishes a subtle predisposition to lightning strikes. As an example....When I was a young lad, my Dad used to love to tell me the story about his experience with a lightning strike that (per Dad) burned his pants and singed his hair, but otherwise left him unscathed. Well Dad's number 3 son --- ME--- has had more than his share of lighning stories. While I was in high school and playing in a summer baseball league, I was positioned at first base and witnessed our pitcher get fried by a lightning bolt that wanted to pass through the pitching rubber. Poor Dale was left lifeless and quite disfigured by that blow. Later on while in college, I came home one early Sat. morning to find my parents home in ashes as it was hit by lightning and promptly burned down before the erstwhile volunteer fire department could arrive. Of course that same house had been hit twice while I lived in it! As an adult, I found myself living in the Peninsula just south of San Francisco in California. One early Spring while the Bay Area was having a very rare thunder storm (about 1 every 3 years) my tower took a direct hit while we were all sleeping. The hit managed to do about $25,000 damage and took its toll in shattered nerves and destroyed wiring and equipment! Well I finally moved to Ithaca on top of a hill and it took less than one year before my first direct hit. However, thanks to Polyphaser and ICE I had minimal damage to my installation. I was standing on the porch with my son Joshua and I noticed in very quick progression that the top of tower had a blue/green ball that soon enveloped all the tower and with the enormous clap I had my first NY state lighning hit. The only damage that I had was some of the galvanizing had been blown off the tower. My antennas were not bothered at all! My installation in NY has 3 10' ground rods outside the base of the tower and bonded with a large copper strap. This is all tied together to a 120' length of the same strap that goes to the nearby wetlands and is connected to another 10' ground rod. I then have ICE boxes for the coax lines and the rotor cables. The coax is also connected to an Alpha Delta-4 coax switch. Just prior to this storm and for all others, I disconnected the coax from the radios and pulled the plug on all the AC sources. It actually worked. Read the stuff from Polyphaser as they seem to have a good handle on what happens. Moral --- be prepared to do what is needed to protect your CONTEST STATION and as soon as genetic engineering science progresses...I am going to have a gene job! 73s Natan, W6XR/2 force12@ibm.net ------------------------------------------------------------------------------ Pete, N4ZR, posted the results of his question re: tower base cement. I have a related question that came to mind. I've heard that the rebar in a tower base should not be connected to the tower because the base may explode if the tower is hit by lightning. However, Rohn sells a 5 foot tower section that is meant to be buried in the base cement. Is the exploding base just a ham myth? 73 Kris AA5UO (->N5KM) mraz@aud.alcatel.com ------------------------------------------------------------------------------ While it's theoretically possible for the base to explode, I've dont know anyone who's had it happen. Actually the tower base is one of the best grounds you can have for your tower if it's big enough and designed properly. This is called a "Ufer" ground. For more information, call Polyphaser and ask them for their lightning protection info kit. It has a wealth of information on different grounding configurations and covers the basic do's and dont's of grounding your station as well as a lot of more "esoteric" solutions for those with unlimited grounding budgets! hi hi 73, Tyler KF3P kf3p@cais.cais.com ------------------------------------------------------------------------------ The HyGain SS(Self Supporting) Crank-ups also use a rebar cage with 3 plates that are above the concrete. The tower then bolts to these plates. As a retired Naval Officer, I have left more than a few of these cages around the U.S. Sort of monuments to Amateur Radio. I always have grounded the tower just outside the concrete block. I now live in the land of thunder storms (FL), have been hit once (Meltdown '92), but not on the tower. It came in through the telephone lines! 73, Hank K2UVG Niceville, FL (Baja Alabama) ------------------------------------------------------------------------------ I believe both the ARRL Antenna Book and the Handbook caution against attaching rebar to the Tower base for this very reason. what is the source of their info?? Tim VE6SH TELLAM@mccarthy.ca ------------------------------------------------------------------------------ How many tower bases have 'exploded' to the PERSONAL knowledge of any ham you know? How many tower bases for TV antennas have exploded in your community? How many radio/tv broadcast towers have had this happen in your community? I rest my case...... Denny K8DO@AOL.COM ------------------------------------------------------------------------------ Living on the lightning-deprived west coast, I've never known of one exploding. Just as a thought, if one were to explode it probably would be from entrapped water being turned to steam. This would imply that you should do your best to seal the area where the tower base goes down into the concrete. If your tower's been up a while, it's probably too late to worry about it, though. 73, Bill W7LZP wrt@eskimo.com ------------------------------------------------------------------------------ This is second-hand info, but I heard about 15 years ago that the W7KW station in AZ experienced an exploding base from a lightning hit. I think I heard this from one of the fellows who went there to take down his towers when he sold out to one of the TDXS guys (NA5R ???). Was it K5RC that told me that? Tom used to be on this forum. Before I appreciated the damage that lightning could do, I had a tower on the Texas Gulf Coast that was only grounded to 3 ground rods that were driven into the bottom of the base hole before the concrete was poured. These ground rods were attached to the tower base inside the concrete with hose clamps. I took many direct hits there without base or antenna damage, tho I did lose a rotator control from time to time. The secret there was the fantastic ground conductivity there. I shunt fed the tower on 160 and had phased 80 meter verticals with NO RADIALS, and they all worked superb with just a ground rod. I will always ground towers outside the base concrete on any future tower installations that I might do. Speaking of new towers, is there any good contest station locations still available in the Austin, TX area? 73, Richard Richard L. King 0007131253@mcimail.com ------------------------------------------------------------------------------ Subj: exploding bases About half the people who responded to this question seem to have assumed it was from me, because I was quoted in the message. Not so. The query came from Kris (AA5UO, mraz@maverick.aud.alcatel.com). I'm skeptical about it, myself, and nobody who e-mailed me has reported personal experience with the alleged phenomenon, while a number reported extensive, negative results. 73, Pete N4ZR@netcom.com ------------------------------------------------------------------------------ Lightning seems to be a BIG topic lately...On Monday evening one of the local weather forcaters had a guest on his program, demonstating a device that 'WARNED' of lightning being with-in 40 miles. Big CONTEST station owners and most anyone with a tower might/could be interested in this electronic device. It is about the size of an HT and the cost is about $200. During the guests 'whole' 30 seconds or so the device was just flashing away....we had a storm nearby.... The unit had 2 or three ranges (scales) on it, one being 8 to 20 miles...this could be very useful and adaptable to letting you know to get the antenna's disconnected etc... For more info contact: Automated Weather Source 2-5 Metropolitan Ct. Gaithersburg MD 20878 301 258-8390 No, i'm not affiliated with them....the XYL just did a great job of writing all the info down.... 73's....bob....K3ZNV biss@epg.nist.gov ------------------------------------------------------------------------------ Seems to me you could build up a small 100khz receiver with some sort of threshold detector and alarm to do the same thing. Come to think of it, I've got one in my airplane called a Stormscope. It is a little pricey for home use, but is just 100khz receiver with a little software. ;-) You could also use a VHF receiver since you only want to detect the closer events. When the squelch breaks on my 2M HT due to a strike, I know it was quite close. Either 10M or 6M would probably be a good compromise for a detector. Bill bills@lvld.hp.com KF0DJ ------------------------------------------------------------------------------ Lots of excellent info on keeping the station 'alive' thru the summer has been posted. I just rcvd the Polyphaser book (YOU NEED THIS BOOK) and was comparing the present ground system vs what is should be, and what to do about it. I've been at this QTH for 12 years now and have had enough damage to want to do it right this time. ... I hope ... :) and noted this idea .... As you review your setup don't forget the 240v line(s) to the amp(s) ! Going to the trouble of the single point ground for the 120v lines, rotors, coax, control lines, etc ... and neglecting the 240v lines is not wise. That still leaves a path for trouble ... In fact the last major electrical related damage here I chalk up to remembering to snatch the 120v lines out of the walls, undoing the coax, but forgetting about the 240v line to the amp. After the flash/pop/smell of "burned air" ... I kept thinking "how did it run in/out along the stn ground" ... then it dawned on me ... the amp was still plugged up ... and it's ground provided a path for the 'bad stuff' to come on down via the gadzillion control lines to remote boxes/rotors/etc ... (lines which were not protected ... nothing in the station was then) I had always figured, heck pull the plugs (120v!) and the coax and not worry ... another idea is that the "bad stuff" came thru the 240v INTO the shack ground ... either way or both, it was an expensive lesson to go thru ... I haven't checked the ICE book yet, but a call to Polyphaser this am finds they do offer a 240v protector that can be mounted on the single point ground. I asked them about NOT doing anything to the 240v and they confirmed my ideas/fears. BTW, the at Polyphaser guy was very prepared to answer questions and make suggestions as to how to do it right the first time. Read the book !!!! Folks, There's not going to be a 'cheap fix' to this topic to do it right. But then again it looks like it's going to be cheaper than my deductable on my home owner's policy if I take another hit, and like someone else mentioned, might just provide a discount ! ... and a whole lot more piece of mind ! 73 Bill AA4NU (aa4nu@raider.raider.net) ------------------------------------------------------------------------------ W0UN told the story at Dayton of watching a thunderstorm march toward his station across the wide open spaces of Colorado, the strikes discontinue when they reached his QTH, then pick up again on the other side, going away. All the hardware apparently is able to dissipate the charge before it becomes lightning. I have occasionally observed a static tic-tic-tic at the end of a coax at my place, with no lightning seemingly around. Rich Boyd KE3Q rlboyd@CapAccess.org ------------------------------------------------------------------------------ I get 500 volts plus, on the 80m loop fed with 450 ohm line, when it is left floating in dry weather... Haven't had the cajones to try it with a thunderstorm overhead... As a farm boy, I quickly learned to avoid touching the electric fence around the 120 acre pasture (yes, with the charger turned off - before you ask - sheesh) in dry weather... This 3/4 mile wire would literally knock you down... It, also, got hit by lightning on a regular basis - and it was my responsibility to disconnect the charger when storms were in the area to keep it from being ruined.... Denny, K8DO@AOL.COM