> On Sep 18, 2017, at 5:31 PM, Don Wilhelm <donw...@embarqmail.com> wrote: > > Wayne, > > Actually, parallel coax runs make a good choice for shielded parallel > feedline. The paralleled LMR-400 lines should produce a feedline > characteristic impedance of 100 ohms. It is normal to connect the shields > together at both ends. At the antenna, the connected shields are left > floating, but at the rig end, are connected to chassis common (your BL2 > ground lug) - perhaps "floating" is what you meant by "unterminated". Are > the shields connected at the antenna end?
Yes. > > As I recall, the matched impedance loss would be twice the loss of a single > run of the coax, but at reasonable distances and the low loss of LMR-400, it > should not be a problem at HF. Agreed. > > The advantages of using parallel coax for a balanced feedline is the same as > using coax over open-wire or ladderline. It can be run on or in the ground, > run next to or thorough conducting metallic surfaces, or coiled up with no > ill effects. That’s what I was dealing with. The house was built in 1929, so in the crawl space there’s legacy plumbing, knob-and-tube wiring, heating ducts, and spider webs that at least look conductive. Wayne N6KR ______________________________________________________________ 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 Message delivered to arch...@mail-archive.com
