You need to be very careful about the balun used in the C-pole. I strongly recommend that you read my original article (QST, April 2004). There are many more details in my book "ARRL Antenna Designer's Notebook". The following is also a very useful link: http://www.qsl.net/hb9mtn/hb9mtn-c-pole.html Good Luck! 73 Brian KF2YN ----- Original Message ----- From: "Rick Karlquist" <richard at karlquist.com> To: "Niel - W0VLZ" <w0vlz at aggienetwork.com> Cc: <antennas at mailman.qth.net> Sent: Wednesday, June 30, 2010 7:47 PM Subject: [Bulk] Re: [Antennas] RG178 B/U / Choke/Balun? > Niel - W0VLZ wrote: >> I have some RG178 B/U I'd like to try as a choke/balun for a light >> weight QRP C-pole (see >> http://w0vlz.blogspot.com/2010/05/c-pole-antenna-for-qrpxpeditions.html >> for my heavy weight model). >>>> I have a 2" diameter coil form. How do I calculate/test for the number >> of turns required to be an effective choke at 14MHz? Right now 15 turns >> of RG8X single layer wound on a 4" plastic coffee can works. >>>> Also, anyone know the attenuation factor of RG178 B/U at HF frequencies? >>>> 73, >> Niel >> You're probably better off putting several turns through > a ferrite toroid or sleeve made of 43 or 61 material. >> The loss of 178 on 20 meters will be something like 6 dB / 100 ft. > Can you at least move up to RG174? >> Rick N6RK >> ______________________________________________________________ > Antennas mailing list > Home: http://mailman.qth.net/mailman/listinfo/antennas > Help: http://mailman.qth.net/mmfaq.htm > Post: mailto:Antennas at mailman.qth.net >> This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html >> __________ Information from ESET NOD32 Antivirus, version of virus > signature database 5241 (20100630) __________ >> The message was checked by ESET NOD32 Antivirus. >> http://www.eset.com >>>