don't forget the velocity factor too! My first thought was to try to find out where the static is coming from in the firstplace and fix that. Why put a band-aid on a cut when you prevent the cut in the first place? Joe WB9SBD
i8cvs wrote: >Hi Lars, OZ1BXM > >The shorted quarter-wave coax line suggested in the ARRL Handbook 2008 and >2009 pages 23.20-21 will work great because it is a short circuit for the >static electricity and a theoretically infinite impedance at the resonant >frequency so that for the RF input signal it is completely ignored by the >input stage of a converter or preamplifier. > >Remember that a quarter-wave transmission line when shorted at one end >shows an infinite impedance in theory at the open end as you can see using >the Smith Chart. > >If you enlarge a shorted quarter-wave by any even or odd number of 1/2 >wavelenght of coax line thing do not changes because a 1/2 wavelenght of >transmission line represents a full turn of the Smith Chart. > >Do it as suggested by the Handbook ! > >73" de > >i8CVS Domenico > >----- Original Message ----- >From: "Lars Petersen" <[email protected]> >To: <[email protected]> >Sent: Tuesday, August 04, 2009 6:01 PM >Subject: [amsat-bb] Avoiding statics on helix antennas > > > > >>Hello AMSAT list, >> >>I have a problem caused by static electricity building up on my two helix >>antennas (23 cm and 13 cm). Two converters have already been zapped, so I >>have to do something about it. >> >>What measure would you recommend to avaoid statics building up on helix >>antennas? >> >>Does anyone have experience using the shorted quarter-wave-stub mentioned >> >> >in > > >>"The ARRL Handbook 2008" pages 23.20-21? >> >>Vy 73, Lars Petersen, OZ1BXM, >>AMSAT-Member 36222, >>[email protected] >>www.oz1bxm.dk >> >>_______________________________________________ >>Sent via [email protected]. Opinions expressed are those of the author. >>Not an AMSAT-NA member? Join now to support the amateur satellite program! >>Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb >> >> > > > > > > >_______________________________________________ >Sent via [email protected]. Opinions expressed are those of the author. >Not an AMSAT-NA member? Join now to support the amateur satellite program! >Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb > > >------------------------------------------------------------------------ > > >No virus found in this incoming message. >Checked by AVG - www.avg.com >Version: 8.5.406 / Virus Database: 270.13.44/2283 - Release Date: 08/05/09 >05:57:00 > > > _______________________________________________ Sent via [email protected]. Opinions expressed are those of the author. Not an AMSAT-NA member? Join now to support the amateur satellite program! Subscription settings: http://amsat.org/mailman/listinfo/amsat-bb
