I have used RG303/U for chokes. A bit smaller diameter than RG400 (0.170 versus 0.195 inches). RG303/U has a solid copper center conductor that is silver plated. The shield for RG303 is also silver plated copper. The jacket is Class 9 Teflon. Also the dielectric material is teflon.
73, Bob Nobis - N7RJN [email protected] > On Feb 6, 2016, at 17:49, Guy Olinger K2AV <[email protected]> wrote: > > If one wants a small 50 ohm coax that will take QRO with a very large > margin and was *designed* for bending and use in aircraft wiring harnesses > then use RG400 to wind around your core. RG400 uses a fine stranded > silvered copper center conductor that is more flexible than its Teflon > dielectric. It has a double shield made from silvered copper strands. > > That's silvered strands whose silver sulphide patina or tarnish is > conductive as opposed to the green copper sulphate that separates copper > strands that have been water soaked. > > Wind the coil form with RG59 to get the length and buy just what RG400 you > need. You can buy brand new RG400 by the foot. With the Teflon dielectric > you can solder the RG400 without worrying about melting it. > > Do it with the good stuff to start with and put it in your will. > > 73, Guy K2AV > > On Saturday, February 6, 2016, Ron D'Eau Claire <[email protected]> wrote: > >> Bob makes an excellent point. I've seen cases where even "solid" dielectric >> did that over time because, after all, it is not really solid. The >> dielectric is plastic so the coax can be bent. >> >> All coax has a minimum bending radius specification. Specific data is >> available on line but, in general, RG58 size cable usually has a minimum >> radius of 1 to 1.5 inches (2.5 to 3.8 cm) and RG8 size cable has a minimum >> radius of at least 2 inches (5 cm). Note that is radius. If you curl the >> cable into a circle the minimum diameter of that circle should be at least >> twice that or 3 to 4 inches (7.5 to 10 cm). >> >> It's not something I've found especially critical in HF applications at >> least around my shack, but tighter bends, which may not actually cause a >> short (yet), alter the impedance as the center conductor migrates toward >> one >> side so it is no longer equally spaced within the shield. This can be a >> serious issue in microwave and even UHF installations. >> >> 73, Ron AC7AC >> >> >> >> -----Original Message----- >> I would have concern that long term usage of RG-8X, being foam core >> dielectric material and bent in a tight radius, may allow the center >> conductor to migrate to the inside radius of the bend. The Minimum Bend >> Radius for RG-8X is 2.50". Thus the tight bend will allow the center >> conductor to short to the shield. A solid core dielectric coax such as >> RG-303 is much preferred. >> >> 73 >> Bob, K4TAX >> >> >> ______________________________________________________________ >> Elecraft mailing list >> Home: http://mailman.qth.net/mailman/listinfo/elecraft >> Help: http://mailman.qth.net/mmfaq.htm >> Post: mailto:[email protected] <javascript:;> >> >> This list hosted by: http://www.qsl.net >> Please help support this email list: http://www.qsl.net/donate.html >> Message delivered to [email protected] <javascript:;> >> > > > -- > Sent via Gmail Mobile on my iPhone > ______________________________________________________________ > 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 > Message delivered to [email protected] > ______________________________________________________________ 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 Message delivered to [email protected]
