Re: Topband: Fw: Choke Construction Info Needed
If you use an automotive spark plug make sure its not the resistor type. Carl KM1H - Original Message - From: "DAVID CUTHBERT" To: "Bob Kupps" Cc: "topband" Sent: Friday, July 27, 2012 8:24 AM Subject: Re: Topband: Fw: Choke Construction Info Needed >I agree with Tom and Bob that the big, heavy choke is not needed. Even it > offers too much inductance to be an effective lightning path. > > A spark gap is the thing to use across the choke or shorted 90 degree > feedline. It should have a weather cover and be set close but not too > close. See ROSS ENGINEERING for a picture of a spark gap. I've use 1/4" > carriage bolts for spark gaps at 1 kA. I would use a larger one for > protection against a direct lightning strike. Only 1% of strikes reach 100 > kA but I think that's a good current to design to. > > http://www.rossengineeringcorp.com/hv_spark_gap.htm > > Dave WX7G > > > > On Thu, Jul 26, 2012 at 7:53 PM, Bob Kupps wrote: > >> Hi Phil >> >> I'm no expert but plan to use a quarter wave shorted stub of RG6 at the >> feed point of my verticals for static drain and harmonic reduction, along >> with a spark gap in the event of a close strike. >> >> 73 Bob >> >> - Forwarded Message - >> From: Phil Clements >> To: topband@contesting.com >> Sent: Friday, July 27, 2012 2:03 AM >> Subject: Topband: Choke Construction Info Needed >> >> I need to construct a heavy-duty choke to be installed from the feed >> point >> of my 160 meter vertical to ground, for static drain and for lightning >> protection. How large does the wire, form, and inductance need to be? >> >> >> >> Thanks in advance for your expertize! >> >> >> >> (((73))) >> >> Phil, K5PC >> >> >> >> ___ >> UR RST IS ... ... ..9 QSB QSB - hw? BK >> ___ >> UR RST IS ... ... ..9 QSB QSB - hw? BK >> > ___ > UR RST IS ... ... ..9 QSB QSB - hw? BK > > > - > No virus found in this message. > Checked by AVG - www.avg.com > Version: 10.0.1424 / Virus Database: 2437/5158 - Release Date: 07/27/12 > ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Re: Topband: Fw: Choke Construction Info Needed
I agree with Tom and Bob that the big, heavy choke is not needed. Even it offers too much inductance to be an effective lightning path. A spark gap is the thing to use across the choke or shorted 90 degree feedline. It should have a weather cover and be set close but not too close. See ROSS ENGINEERING for a picture of a spark gap. I've use 1/4" carriage bolts for spark gaps at 1 kA. I would use a larger one for protection against a direct lightning strike. Only 1% of strikes reach 100 kA but I think that's a good current to design to. http://www.rossengineeringcorp.com/hv_spark_gap.htm Dave WX7G On Thu, Jul 26, 2012 at 7:53 PM, Bob Kupps wrote: > Hi Phil > > I'm no expert but plan to use a quarter wave shorted stub of RG6 at the > feed point of my verticals for static drain and harmonic reduction, along > with a spark gap in the event of a close strike. > > 73 Bob > > - Forwarded Message - > From: Phil Clements > To: topband@contesting.com > Sent: Friday, July 27, 2012 2:03 AM > Subject: Topband: Choke Construction Info Needed > > I need to construct a heavy-duty choke to be installed from the feed point > of my 160 meter vertical to ground, for static drain and for lightning > protection. How large does the wire, form, and inductance need to be? > > > > Thanks in advance for your expertize! > > > > (((73))) > > Phil, K5PC > > > > ___ > UR RST IS ... ... ..9 QSB QSB - hw? BK > ___ > UR RST IS ... ... ..9 QSB QSB - hw? BK > ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
Topband: Fw: Choke Construction Info Needed
Hi Phil I'm no expert but plan to use a quarter wave shorted stub of RG6 at the feed point of my verticals for static drain and harmonic reduction, along with a spark gap in the event of a close strike. 73 Bob - Forwarded Message - From: Phil Clements To: topband@contesting.com Sent: Friday, July 27, 2012 2:03 AM Subject: Topband: Choke Construction Info Needed I need to construct a heavy-duty choke to be installed from the feed point of my 160 meter vertical to ground, for static drain and for lightning protection. How large does the wire, form, and inductance need to be? Thanks in advance for your expertize! (((73))) Phil, K5PC ___ UR RST IS ... ... ..9 QSB QSB - hw? BK ___ UR RST IS ... ... ..9 QSB QSB - hw? BK
