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Total 22 documents matching your query.

1. Topband: Spark gaps (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Fri, 27 Jul 2012 10:09:16 -0400; Has anyone looked at, or looked for, cheap electric fence gaps?? My system copper pipes near tower legs work great for me on rigid towers, I can bend them so they spring away from the tower and then; /archives//html/Topband/2012-07/msg00359.html (8,874 bytes)
2. Re: Topband: Spark gaps (score: 1): Author: DAVID CUTHBERT <telegrapher9@gmail.com>; Date: Fri, 27 Jul 2012 08:35:13 -0600; Yes a direct hit should vaporize a spark plug. For a 100 kA hit two 1" diameter rounded steel balls may survive. Note that Ross Engineering uses carbon balls on their spark gaps. At 50 kA/us every in; /archives//html/Topband/2012-07/msg00361.html (9,187 bytes)
3. Re: Topband: Spark gaps (score: 1): Author: <donovanf@starpower.net>; Date: Fri, 27 Jul 2012 10:57:38 -0400 (EDT); An air gap using one to two inch diameter balls with only a one or two millimeter gap provides a nearly uniform field resulting in the fastest breakdown at repeatable and fairly breakdown voltages bu; /archives//html/Topband/2012-07/msg00362.html (10,362 bytes)
4. Re: Topband: Spark gaps (score: 1): Author: "Bill Wichers" <billw@waveform.net>; Date: Fri, 27 Jul 2012 11:06:12 -0400; You can get chrome steel balls too and they are *very* hard (usually used for ball bearings). You have to drill them with solid carbide drills. I don't think it would be possible to thread the holes; /archives//html/Topband/2012-07/msg00364.html (8,784 bytes)
5. Re: Topband: Spark gaps (score: 1): Author: Mike Waters <mikewate@gmail.com>; Date: Fri, 27 Jul 2012 10:33:22 -0500; I don't think carbon balls are suitable for lightning protection. Think of the voltage drop that would appear across each ball during a direct hit. I think they would vaporize. At http://www.rossengi; /archives//html/Topband/2012-07/msg00365.html (9,473 bytes)
6. Re: Topband: Spark gaps (score: 1): Author: DAVID CUTHBERT <telegrapher9@gmail.com>; Date: Fri, 27 Jul 2012 09:39:43 -0600; Google "carbon ball gap lightning." _______________________________________________ UR RST IS ... ... ..9 QSB QSB - hw? BK; /archives//html/Topband/2012-07/msg00367.html (9,892 bytes)
7. Re: Topband: Spark gaps (score: 1): Author: DAVID CUTHBERT <telegrapher9@gmail.com>; Date: Fri, 27 Jul 2012 09:43:30 -0600; www.rossengineeringcorp.com/toroids_spheres_coronary_nuts.htm Ross recommends carbon for lightning. _______________________________________________ UR RST IS ... ... ..9 QSB QSB - hw? BK; /archives//html/Topband/2012-07/msg00368.html (9,812 bytes)
8. Re: Topband: Spark gaps (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Fri, 27 Jul 2012 11:52:06 -0400; I agree. The last thing we want is high surface resistivity, unless we want something to heat and vaporize. With high core resistivity, we could make it explode. :-) _________________________________; /archives//html/Topband/2012-07/msg00369.html (9,049 bytes)
9. Re: Topband: Spark gaps (score: 1): Author: DAVID CUTHBERT <telegrapher9@gmail.com>; Date: Fri, 27 Jul 2012 13:42:42 -0600; _______________________________________________ UR RST IS ... ... ..9 QSB QSB - hw? BK; /archives//html/Topband/2012-07/msg00371.html (10,028 bytes)
10. Re: Topband: Spark gaps (score: 1): Author: Mike Waters <mikewate@gmail.com>; Date: Fri, 27 Jul 2012 15:18:28 -0500; Man, I don't know, Dave. How long have they been selling those carbon balls for that purpose? I don't have the figures in front of me, but carbon has a significant amount of resistance. (Maybe that's; /archives//html/Topband/2012-07/msg00372.html (10,671 bytes)
11. Re: Topband: Spark gaps (score: 1): Author: "Tom W8JI" <w8ji@w8ji.com>; Date: Fri, 27 Jul 2012 16:29:15 -0400; I've never seen a carbon ball in a lightning gap application. I'd have to see a few after being in action a long time before trusting them. Broadcast stations use hard metallic balls, as do electric; /archives//html/Topband/2012-07/msg00373.html (9,778 bytes)
12. Re: Topband: Spark gaps (score: 1): Author: DAVID CUTHBERT <telegrapher9@gmail.com>; Date: Fri, 27 Jul 2012 14:42:06 -0600; Mike, here it is. The resistivity of amorphous carbon is 35 u ohm meters (That's a 1 meter cube) A 1" cube has a resistivity of 1.4 m ohms, a one inch sphere about 3 m ohms. 100 kA for 20 us dumps 60; /archives//html/Topband/2012-07/msg00374.html (11,454 bytes)
13. Re: Topband: Spark gaps (score: 1): Author: <donovanf@starpower.net>; Date: Fri, 27 Jul 2012 17:26:08 -0400 (EDT); This link shows the base of a typical AM broadcast tower, with two hard steel balls used as lightning protection. At kilowatt power levels its not unusual to use a credit card to set the gap. http://; /archives//html/Topband/2012-07/msg00376.html (10,644 bytes)
14. Re: Topband: Spark gaps (score: 1): Author: Mike Waters <mikewate@gmail.com>; Date: Fri, 27 Jul 2012 16:26:50 -0500; Thanks, Dave. That's amazing, and I won't argue anymore, even though I didn't (and probably won't) check your figures. I would have thought that the carbon sphere would have a MUCH greater resistance; /archives//html/Topband/2012-07/msg00377.html (9,401 bytes)
15. Re: Topband: Spark gaps (score: 1): Author: "kd9sv" <kd9sv@comcast.net>; Date: Fri, 27 Jul 2012 17:31:21 -0400; Silly me, and to think they were probably referring to "Carbon Steel Balls" not Carbon balls...de gary This link shows the base of a typical AM broadcast tower, with two hard steel balls used as ligh; /archives//html/Topband/2012-07/msg00378.html (10,160 bytes)
16. Re: Topband: Spark gaps (score: 1): Author: DAVID CUTHBERT <telegrapher9@gmail.com>; Date: Fri, 27 Jul 2012 16:04:05 -0600; I do make (all too frequent) mistakes so check away. Carbon is 2000 times more resistive than copper. Being more resistive the carbon skin depth at lightning frequencies is much deeper than copper or; /archives//html/Topband/2012-07/msg00379.html (9,719 bytes)
17. Re: Topband: Spark gaps (score: 1): Author: "N2TK, Tony" <tony.kaz@verizon.net>; Date: Fri, 27 Jul 2012 19:48:03 -0400; As a side note, last night when the storm came barreling in with very strong winds I was watching the tower as the elements whipped around. Bang! First time I saw a direct hit on the tower. Had spots; /archives//html/Topband/2012-07/msg00380.html (11,166 bytes)
18. Re: Topband: Spark gaps (score: 1): Author: Guy Olinger K2AV <olinger@bellsouth.net>; Date: Sat, 28 Jul 2012 01:05:56 -0400; What is the condition of your 160m radials after the lightning strike? 73, Guy. _______________________________________________ UR RST IS ... ... ..9 QSB QSB - hw? BK; /archives//html/Topband/2012-07/msg00382.html (12,446 bytes)
19. Re: Topband: Spark gaps (score: 1): Author: Jim WA9YSD <wa9ysd@yahoo.com>; Date: Fri, 27 Jul 2012 22:47:59 -0700 (PDT); Take 2 rods and grind a point on each rod. Point the points toward each other. There is your spark gap. You can do the dame thing with copper flat stock used on building grounds in electrical valts.; /archives//html/Topband/2012-07/msg00383.html (6,501 bytes)
20. Re: Topband: Spark gaps (score: 1): Author: "Gregg W6IZT" <w6izt1@bellsouth.net>; Date: Sat, 28 Jul 2012 07:16:12 -0400; I took a lightning strike to my shunt fed tower crank up earlier this year. It vaporized the #8 wire that ran from the top to the bottom of the tower. Some of the radials turned into fuses. Interesti; /archives//html/Topband/2012-07/msg00384.html (13,011 bytes)

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