Re: [Elecraft] static charges
The first thing that comes to mind is a switch that would ground the antennas when you disconnect them. Next thought is a path to ground when you are using them or not. That could be an RFC (Radio frequency choke) to ground or perhaps a resistor to bleed off the charge. Use of grounded antennas may be another possibility. That might be a loop antenna that is grounded at one end. Another could be a vertical with a matching network that provides a ground path. A description of the antennas that you have or intend to use would be useful to provide more specific suggestions! 73 - Mike WA8BXN __ 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] static charges
Hi Scott, I've drawn an arc from an 80m dipole at 30 feet on a dry sunny day, with the dry south wind blowing, that is over a half inch long... and it is repetitive. That is enough voltage and current to cook most any solid state device.. ... and will do damage if left to its own accord. What I get from my antennas now, that are 360 foot long and at 50 feet, is absolutely astounding, when observed in a dark room, from the open line feeders. What to do? Simple, and it works right easy too. Provide a straight... no.. really straight line to ground from the feedline. If you are using coax, then a gas tube discharge will work, and ground it with a very straight to ground path. No bends. And at the shack end, put a connector.. or coax T in the line, and solder a 1 meg resistor across the bottom of the T, from center to ground. That eliminates the static. Yes, you'll still need to disconnect when not using.. but it will allow you to use the antennas when the wind blows and the lightening isn't. Now for open lines.. it is even easier. when the line gets close to entry, take a gas tube discharge on each line.. and put the 1 meg resistor from each side of the feedline to the case or shell of the discharge. Keep them in a sheltered from rain case... that works well with a sealed like a Glad or Rubbermaid container.. with slits cut for the feedline to go through. Now you're safer from all the tracks of loose and unguided electrons that are of a mind for wanton distruction. good luck, and remember.. disconnect is always best.. IF it is a long ways away from anything else. --... ...-- Dale - WC7S in Wy __ 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] static charges
Provide a dc path to ground at all times. A 20K to 50K ohm resistor across your antenna feed line hot side to ground will constantly dissipate accumulating static while not interfering with the operation of the antenna (50K is 1,000 times larger than the antenna impedance if the antenna is somewhat resonant and fed with 50 ohm coax, and few antennas - even a random wire - present more than 4K or 5k impedance if not.) Your antenna does not "attract" static but makes it more obvious. A grounded structure in the air (tower, lightning rod, antenna, etc.) *reduces* the static charge in the immediate area by constantly feeding electrons from the earth into the atmosphere to neutralize the positive charge that accumulates there. That's of little value if the charge escalates faster than the ability of the system to neutralize it and you get a lightning bolt, but it points out that grounded structures actually *decrease* the likelihood of lightning, but may *increase* the chance of lightning striking them if a bolt occurs. Ron AC7AC -Original Message- From: elecraft-boun...@mailman.qth.net [mailto:elecraft-boun...@mailman.qth.net] On Behalf Of Scott McDowell Sent: Thursday, April 21, 2011 7:42 PM To: elecraft@mailman.qth.net Subject: [Elecraft] static charges Hello I live at 3600 feet altitude on the Texas high plains where it is extremely dry, and we have a lot of wind. And lots of static eletricity. I have static charges jump as much as 3/4 of an inch to my hands daily, and usually several times a day. How can I protect my transceivers from this. I keep them grounded and the antennas disconnected when not being used. but sometimes I believe this attracks the static charges. I also keep them disconnected when not being used How can I protect the rigs from static??? __ 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] static charges
Scott, If you are referring to a static spark from your hand to the grounded equipment chassis, then I suggest purchasing a lot of "Static Guard" - that is the garment spray sold to eliminate static cling in clothing. Before touching the equipment, spray your chair, the carpet in the immediate vicinity and your clothing with the Static Guard. If you can eliminate any carpeting from the operating area, that will help a lot. Those static discharges will not usually harm equipment IF the equipment enclosure is metal and it is well grounded. The static charge should ideally flow to ground on the outside of the equipment enclosure - but then ideal conditions do not always exist, and your reasons for concern are valid. 73, Don W3FPR 73, Don W3FPR On 4/21/2011 10:41 PM, Scott McDowell wrote: > Hello > I live at 3600 feet altitude on the Texas high plains where it is extremely > dry, > and > we have a lot of wind. And lots of static eletricity. I have static charges > jump > as > much as 3/4 of an inch to my hands daily, and usually several times a day. > How can I protect my transceivers from this. I keep them grounded and the > antennas disconnected when not being used. but sometimes I believe this > attracks > the static charges. I also keep them disconnected when not > being used > How can I protect the rigs from static??? > __ > 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
