On 12/31/2011 9:14 PM, Phil Hystad wrote: > Or, maybe a 1:1 balun right at the antenna feed point with coax the remaining > distance to the shack?
No question -- 50 ohm coax wound around one or more #31 or #43 ferrite cores to form a common mode choke. See http://audiosystemsgroup.com/RFI-Ham.pdf The choke will completely kill any radiation or pickup from the feedline. If the antenna were a lot higher, I'd use 75 ohm coax. And yes, tweak the length for 7.1 MHz. Also see two applications notes about "antennas for limited space" on my website. A single 2-wire fan dipole cut for 80M and 40M and fed with 50 ohm coax will also work great on 30M, 17M, 15M, and 12M, and using the same choke to kill feedline current. To minimize feedline loss on 30, 17, 15, and 12, use RG8 rather than RG8X or RG58. This antenna will work as well as the single-band 40M dipole on 40M. You WILL need an antenna tuner, like the KAT3. http://audiosystemsgroup.com/publish.htm 73, Jim K9YC ______________________________________________________________ Elecraft mailing list Home: http://mailman.qth.net/mailman/listinfo/elecraft Help: http://mailman.qth.net/mmfaq.htm Post: mailto:[email protected] This list hosted by: http://www.qsl.net Please help support this email list: http://www.qsl.net/donate.html
