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 <r...@cobi.biz> 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:Elecraft@mailman.qth.net <javascript:;> > > This list hosted by: http://www.qsl.net > Please help support this email list: http://www.qsl.net/donate.html > Message delivered to k2av....@gmail.com <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: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
