Re: [Elecraft] [OT] Grounding Antenna when not in use
Do some study on the subject and take whatever measures toward the ideal solution that are practical for you. I might add again here that *all* ground rods must be tied to the utility ground rod with heavy wire. That is protection for you and your equipment under elecrtical fault conditions. That's good advice. It's a national electrical code requirement that the station ground has to be tied to the mains ground, not just for power line faults or equipment faults but also for lightning. Assuming we have a normal height antenna and above-ground utilities, most hits that cause damage are on power lines. The surge runs through the power lines to ground through our gear if the equipment ground is not bonded to the mains ground. The opposite is true also if the antenna gets hit. Bonding the station ground to the mains ground diverts current from that path through the house. While disconnecting an antenna does help for close hits or static buildup, the devil is in the fine details of how we do thingsnot what we think we do. __ 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
Re: [Elecraft] [OT] Grounding Antenna when not in use
Ad Don points out very well, disconnect is best. Why? There are many white papers about that will dazzle you with there brilliance and take a lot of your time, how about I skin it for you? Because: And electrical flow/current will follow Kirkov's law. agreed? There fore, follow the flow of a direct hit, down the tower.. now the hit was to the tower. As the current flows down the tower, voltage is induced... into the feedline that is strapped to the tower. (that is the way transformers work, right?) So the current gets to the ground, but just before that.. it sees two paths.. the one to ground.. and the one along the feed line... or cable carrier (wire support or rack), so it flows both ways. Lets follow the one along the feedline... It gets to a polyphasor... spark gap or choke, good.. it sees two paths again... ok.. follow the one on in... and the path to ground may cause induction into? But the one in.. past the spark gap, goes on in.. and flows along ... how far? ... next to? ... towards an unprotected (now) rx amp or tr contact or but wait.. how much voltage is it now? How much damage can it really cause? Consider what the breakdown voltage of that diode junction really is... then consider that the hit had... oh... say 100,000 volts and at each divider point it dropped 80 percent... you have two maybe three points? lets see.. the math.. oh no.. the math... 80% of 100k.. and 80% of ... and maybe 80% of guess what... I figure, that you may get close. may get close to saving that diode. But... I also figure that my 80%... maybe 90... or it may be 70 and I would really rather play radio, than play with numbers so I disconnect... all the radios. and I have still heard the coax zapping, during a storm. I'm thinking that is enough to cook a junction. --... ...-- Dale - WC7S in Wy Grounding the antenna is not as important as disconnecting the transceiver from the feedline when no in use. _ Hotmail: Trusted email with powerful SPAM protection. http://clk.atdmt.com/GBL/go/210850553/direct/01/ __ 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
Re: [Elecraft] [OT] Grounding Antenna when not in use
My antennas come in to one manual selector switch, which connects the selected antenna to a second selector switch, which then connects that to the desired rig. Both switches ground unselected inputs. Since the K3 is switched to ANT1 when powered down, I keep my Cantenna connected to the ANT1 input and I use ANT2, which connects to that second selector switch. The K3 remembers that I like ANT2 when I power up, so that's no hassle. If I accidentally transmit into ANT1, there's a dummy load there. So I have some level of protection even if I forget to rotate both switches to ground or unused inputs when not operating. I usually do remember though, since I also lost my SWR / power measuring diodes to a nearby lightning strike, so I've got several levels of protection. I admit this isn't as good as disconnecting coax, but I'd never get on the air if I had to go through all of that every time I turned on the rig. Some guys disconnect everything and throw it outside, seal the rig in the original shipping carton, sacrifice a goat and pray a novena when thunder approaches, but I can't go that far. I think my next logical step would be to have the AC plug for my K3's power supply handy at desktop level so I can easily pull it when I'm going to be away from the rig for a while. This in response to what W8JI said about the mains connection being the primary path for damage. 73-Nick, WA5BDU .hank. wrote: Chuck . Like you, I have never had to disconnect any radios in the past from the antenna - except during severe thunder storms. About a year ago when the SWR SMT diodes went bad in my K3, I admitted to K3 support that I did not remove the coax from the back of the K3 but I grounded the Six Pak switch connections out in the garage. __ 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
Re: [Elecraft] [OT]Grounding Antenna when not in use
Dale, WC7S wrote: I disconnect... all the radios. and I have still heard the coax zapping, during a storm. I'm thinking that is enough to cook a junction. End snip I've heard that eerie ticking coming from my lightening bug arrester. This ticking increases to a buzz as the storm gets closer. I've often wondered why more hams haven't become SK. First, they construct this big lightening catcher in their yard, and then they run a very good conductor into the house! Diodes are the least of my worries. Speaking of diodes, back in the good ol daze, vacuum tubes could take a lot of abuse and heal up. But solid state devices don't heal up; they suffer from tunneling, which is permanent. The best advice is to disconnect both the antenna and power if you live in an area where lightening is prevalent. Fortunately for me, I moved to S. California to be near the grandkids. Lightening storms out here are so rare that if you hear a clap of thunder, you are sure to read about it in paper the next day. 73, Fred, K3 2241 __ 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
Re: [Elecraft] [OT]Grounding Antenna when not in use
Back in the 60's when I was in Wash DC VA suburbs, and pretty green about things electrical, I had a 40m vertical that used the boom/parasitic elements of my tribander as a counterpoise. The shield was at DC ground from the tower. The center conductor was straight from the vertical. I kept it disconnected unless in use. When a thunderstorm approached it would periodically kzap across the PL259, with the frequency increasing as the storm approached, sometimes getting to 5 or 10 kzaps per second. I put it on a panel style DC meter once and got half scale-ish current that varied wildly and increased as storm near, going to peg. I don't recall the sensitivity of the meter. The top of the vertical was at about 105 feet. It was never struck that I know of. The one close strike was to blow a 15 foot mimosa tree into toothpicks. The tree was twenty feet from either house and about 100 feet away from the tower. The tower extended about a foot and a half into dirt below 5' of concrete for the base, so it was grounded. Along with many other risky episodes in my teens and early twenties, I wonder how I survived being electrocuted, smoked, crushed, burned 73, Guy. On Sat, Mar 20, 2010 at 11:59 AM, Fred Atchley hamkt...@att.net wrote: Dale, WC7S wrote: I disconnect... all the radios. and I have still heard the coax zapping, during a storm. I'm thinking that is enough to cook a junction. End snip I've heard that eerie ticking coming from my lightening bug arrester. This ticking increases to a buzz as the storm gets closer. I've often wondered why more hams haven't become SK. First, they construct this big lightening catcher in their yard, and then they run a very good conductor into the house! Diodes are the least of my worries. Speaking of diodes, back in the good ol daze, vacuum tubes could take a lot of abuse and heal up. But solid state devices don't heal up; they suffer from tunneling, which is permanent. The best advice is to disconnect both the antenna and power if you live in an area where lightening is prevalent. Fortunately for me, I moved to S. California to be near the grandkids. Lightening storms out here are so rare that if you hear a clap of thunder, you are sure to read about it in paper the next day. 73, Fred, K3 2241 __ 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 __ 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
Re: [Elecraft] [OT] Grounding Antenna when not in use
Maybe I can throw this in here quickly while we're on the subject of lightning. For a long time I have wanted to have a list of lightning strikes by county, but have never been able to find such a statistic on the web. Has anyone ever run across this information? Please respond privately to reduce reflector traffic. Al W6LX __ 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
Re: [Elecraft] [OT]Grounding Antenna when not in use
Guy's story reminds me of an experience in my teenage days when I had a tri-band, 2 element cubical quad on a 40 foot tower. I had made a crude grounding rack for the separate feedlines using nails appropriately spaced in a scrap 2x4 to hang the PL-259s, and the nails were grounded to the mains ground with some wire braid stripped from old coax. I returned home from a family vacation one summer to find the PL-259s welded to the nails. There was no sign of other damage, so there must have been a relatively gentle surge induced by lightning. I don't recommend my grounding technique (I was 14 or 15 and pretty naive about lightning-induced currents), but I still disconnect feedlines (and ground them!) religiously. Mike, K8CN -- View this message in context: http://n2.nabble.com/Re-OT-Grounding-Antenna-when-not-in-use-tp4768946p4770901.html Sent from the Elecraft mailing list archive at Nabble.com. __ 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
Re: [Elecraft] [OT] Grounding Antenna when not in use
A ground bus from The Wireman greatly simplifies the process. 73, Steve Kercel AA4AK Charles Teeter wrote: Hello: After I get my kit built, I¹ll be operating with a windom antenna on 40 10. It¹s been suggested that when I¹m not operating, I should disconnect the rig from the antenna and run the antenna to ground. I¹ve never done that in the past when I operated with wire antennas or my vertical, but it does make sense as a safety precaution. I¹m wondering if anyone has any suggestions about the best way(s) to do that? Are there any pieces of equipment that you would recommend to simplify the process? Any help would be greatly appreciated. Thanks. 73, Chuck KE9CE __ 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 __ 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
Re: [Elecraft] [OT] Grounding Antenna when not in use
I might make a suggestion. It is terribly easy to forget to throw the switch. What I do when I need such a precaution, I put a 20 A SPST 12VDC coil relay connected to the switched 12 VDC output. When the K3 is is the energized mode the antenna is passed to the K3, when the K3 is off, the antenna is grounded. Mel, K6KBE --- On Fri, 3/19/10, Stephen W. Kercel kerc...@suscom-maine.net wrote: From: Stephen W. Kercel kerc...@suscom-maine.net Subject: Re: [Elecraft] [OT] Grounding Antenna when not in use To: Charles Teeter c.tee...@att.net Cc: Elecraft@mailman.qth.net Date: Friday, March 19, 2010, 3:19 PM A ground bus from The Wireman greatly simplifies the process. 73, Steve Kercel AA4AK Charles Teeter wrote: Hello: After I get my kit built, I¹ll be operating with a windom antenna on 40 10. It¹s been suggested that when I¹m not operating, I should disconnect the rig from the antenna and run the antenna to ground. I¹ve never done that in the past when I operated with wire antennas or my vertical, but it does make sense as a safety precaution. I¹m wondering if anyone has any suggestions about the best way(s) to do that? Are there any pieces of equipment that you would recommend to simplify the process? Any help would be greatly appreciated. Thanks. 73, Chuck KE9CE __ 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 __ 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 __ 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
Re: [Elecraft] [OT] Grounding Antenna when not in use
I use a MFJ-4726/4726RC powered 6x6 port antenna switch. All non-selected inputs are always grounded, and the unit automatically grounds everything when you shut off power, or when you turn off your transceiver. Phil - AD5X __ 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
Re: [Elecraft] [OT] Grounding Antenna when not in use
After I get my kit built, I¹ll be operating with a windom antenna on 40 10. It¹s been suggested that when I¹m not operating, I should disconnect the rig from the antenna and run the antenna to ground. I¹ve never done that in the past when I operated with wire antennas or my vertical, but it does make sense as a safety precaution. I¹m wondering if anyone has any suggestions about the best way(s) to do that? Are there any pieces of equipment that you would recommend to simplify the process? Any help would be greatly appreciated. Thanks. Chuck, Nearly all the time when there is serious damage, it comes from a loop from power lines to your antenna and station ground. http://www.w8ji.com/ground_systems.htm You either MUST have a proper station ground bonded to the power mains ground and a bulkhead entrance, or you really would have to take the rig totally out of line. No power supply connections, computer connections, antenna, or anything. Although it is popular, grounding the antenna when off really means next to nothing. It can help if a hit is a mile away, or from p-static charging, but it won't do a thing if lightning hits the mains (very common) or the antenna (very rare unless you have a tall tower). For automatic antenna disconnect and static shielding you really need a double-make double-break relay, in a proper box with proper layout, to totally isolate the center conductor. It has to be a properly configured double-make double-break that grounds the transfer bar when the relay is off. Any other type of relay or switch is not secure at all. Tom __ 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
Re: [Elecraft] [OT] Grounding Antenna when not in use
Well, I guess I've had some very rare hits since my TA33 at 25' on my parent's home years ago got hit by lightning and my Cushcraft R7000 vertical mounted at 10' above the ground got hit just 5 years ago here in Texas. My radios were disconnected from the feedline, but still connected to everything else. No damage in the shack in either case except during the recent hit, my DSL modem was taken out. My neighbor's wife happened to be looking out her kitchen window and saw the lightning hit the vertical. The coax feedline to the antenna went down to ground level, next to my pool filter motor and then into the house. The lightning grounded through the pool filter pump motor - blowing a hole in the side of the coax http://nj-bob.smugmug.com/Radio-Stuff/Lightning-Strike-052505/556399_qL6ML#2 3130433_v6ezB-A-LB It toasted the filter pump motor, the freeze protector and also the pool heater. All of it had to be replaced. The antenna's matching network exploded and sent shards of plastic flying all over the yard and in the pool. More photos here: http://nj-bob.smugmug.com/Radio-Stuff/Lightning-Strike-052505/556399_qL6ML#2 3130442_qkYFL I wonder if I had the antenna grounded through some sort of protective device that I might have avoided the resulting damage? 73, Bob W5OV -Original Message- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Tom W8JI Sent: Friday, March 19, 2010 6:36 PM To: Charles Teeter; Elecraft@mailman.qth.net Subject: Re: [Elecraft] [OT] Grounding Antenna when not in use After I get my kit built, I¹ll be operating with a windom antenna on 40 10. It¹s been suggested that when I¹m not operating, I should disconnect the rig from the antenna and run the antenna to ground. I¹ve never done that in the past when I operated with wire antennas or my vertical, but it does make sense as a safety precaution. I¹m wondering if anyone has any suggestions about the best way(s) to do that? Are there any pieces of equipment that you would recommend to simplify the process? Any help would be greatly appreciated. Thanks. Chuck, Nearly all the time when there is serious damage, it comes from a loop from power lines to your antenna and station ground. http://www.w8ji.com/ground_systems.htm You either MUST have a proper station ground bonded to the power mains ground and a bulkhead entrance, or you really would have to take the rig totally out of line. No power supply connections, computer connections, antenna, or anything. Although it is popular, grounding the antenna when off really means next to nothing. It can help if a hit is a mile away, or from p-static charging, but it won't do a thing if lightning hits the mains (very common) or the antenna (very rare unless you have a tall tower). For automatic antenna disconnect and static shielding you really need a double-make double-break relay, in a proper box with proper layout, to totally isolate the center conductor. It has to be a properly configured double-make double-break that grounds the transfer bar when the relay is off. Any other type of relay or switch is not secure at all. Tom __ 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 __ 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
Re: [Elecraft] [OT] Grounding Antenna when not in use
Chuck . Like you, I have never had to disconnect any radios in the past from the antenna - except during severe thunder storms. About a year ago when the SWR SMT diodes went bad in my K3, I admitted to K3 support that I did not remove the coax from the back of the K3 but I grounded the Six Pak switch connections out in the garage. They were adamant that the diodes went bad because of something like residual static build-up and they would supply the replacement diodes, but not replace them under warranty. I struggled with the replacement (I hate SMT, but that's my problem). I now remove the K3's coax where it comes in the house before I leave the shack even though the rating of the original diodes was increased to (I think) 70VDC. It's better to be safe than sorry! 73HankK8DD -- View this message in context: http://n2.nabble.com/OT-Grounding-Antenna-when-not-in-use-tp4765766p4766679.html Sent from the Elecraft mailing list archive at Nabble.com. __ 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
Re: [Elecraft] [OT] Grounding Antenna when not in use
Chuck, Grounding the antenna is not as important as disconnecting the transceiver from the feedline when no in use. I have a relay switching arrangement for my shack which connects the transceiver to a dummy load when no antenna is connected, and my remote antenna relays connect unused antennas to ground (at that remote location). I also have spark-gap surge protectors in the shack across each feedline. As Tom W8JI pointed out, this may not be adequate protection, but I figure it helps, even if just a little bit. I think Tom is referring to lightning damage to an installation, but I believe my precautions help protect the receiver front end from nearby lightning induced surges. I fully realize these measures are woefully ineffective for a direct strike - I do have additional protection against strong surges - all power, control circuits, telco and LAN cabling in the hamshack come through a grounding window and I have installed PolyPhaser protective devices at the place where all lines enter the building, and I have an extensive grounding system. I still do not trust it - when lightning is near, I stay away from the hamshack area. Do some study on the subject and take whatever measures toward the ideal solution that are practical for you. I might add again here that *all* ground rods must be tied to the utility ground rod with heavy wire. That is protection for you and your equipment under elecrtical fault conditions. 73, Don W3FPR Charles Teeter wrote: Hello: After I get my kit built, I¹ll be operating with a windom antenna on 40 10. It¹s been suggested that when I¹m not operating, I should disconnect the rig from the antenna and run the antenna to ground. I¹ve never done that in the past when I operated with wire antennas or my vertical, but it does make sense as a safety precaution. I¹m wondering if anyone has any suggestions about the best way(s) to do that? Are there any pieces of equipment that you would recommend to simplify the process? Any help would be greatly appreciated. Thanks. __ 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
