Mel, I have seen comparable specs on RG303 versus RG400, however, some cable manufacturers have specified a larger bending radius for both cables. Not sure why?
I wonder if anyone has actually run tests of coax showing the real impact of bending with a small radius, comparable to what one would see in a typical common mode choke? 73 Bob Nobis - N7RJN [email protected] > On Feb 7, 2016, at 15:53, Mel Farrer <[email protected]> wrote: > > SORRY, but the min static bending radius for RG-303 is 25 mm and RG-400 is 35 > mm. For torroid wrap which is better????? > > Mel, K6KBE > > > From: Chuck Catledge <[email protected]> > To: 'Guy Olinger K2AV' <[email protected]>; 'Robert Nobis' <[email protected]> > Cc: [email protected]; 'Ron D'Eau Claire' <[email protected]> > Sent: Sunday, February 7, 2016 2:31 PM > Subject: Re: [Elecraft] Balun Questions > > At hamfests around the Southeast, surplus RG400 is often found in terminated > cables (usually BNC or N) in lengths up to around 20 feet. The price I've > paid is always less than $1.00 per foot, sometimes much less. I've used it > to make dozens of RF chokes (1:1 baluns). The small size of RG400 allows the > use of a single medium to large clamp-on #31 ferrite that works effectively > from 10-160M, conditioned by the number of turns. The large snap-on ferrite > will accommodate 10-12 turns; the medium snap-on will handle 5-6 turns. Jim, > K9YC's tutorials are excellent. Consult the Fair-Rite website for additional > technical data. > > BTW, the Teflon dielectric allows easy soldering in PL-259s with RG-58 > reducers without any fear of melting the dielectric. > --- > Chuck, AE4CW > > -----Original Message----- > From: Guy Olinger K2AV [mailto:[email protected] > <mailto:[email protected]>] > Sent: Sunday, February 07, 2016 01:08 > To: Robert Nobis <[email protected] <mailto:[email protected]>> > Cc: [email protected] <mailto:[email protected]>; Ron D'Eau > Claire <[email protected] <mailto:[email protected]>>; Guy Olinger K2AV > <[email protected] <mailto:[email protected]>> > Subject: Re: [Elecraft] Balun Questions > > RG303 is not rated for the tight bends. RG400 with its fine stranded center > conductor is rated for corner bends in aircraft wiring harnesses and will not > deform the dielectric within the bends. I would not wind any solid center > conductor coax on a toroid. > > I would only buy cut lengths of RG400 after the lengths for a project are > known. Some number of such suppliers on eBay. One currently listed at 1.98 > per foot: > http://www.ebay.com/itm/RG400-Coaxial-Cable-Mil-spec-by-the-ft-US-supplier-/251260159394?hash=item3a8045c5a2:g:WpAAAOxy43FRafUe > > <http://www.ebay.com/itm/RG400-Coaxial-Cable-Mil-spec-by-the-ft-US-supplier-/251260159394?hash=item3a8045c5a2:g:WpAAAOxy43FRafUe> > > True it ain't ham cheep. The good stuff that lasts and lasts almost never is. > Back in the early days of eBay I came by a 142' length of RG400 for $25. > That's $0.178 a foot I also came by bundles of miscellaneous 6 foot to 15 > foot jumpers with various connectors on end for similar ridiculous low prices > per foot. > > The silvered copper strands stand up to migration of dampness in a way not > possible with same size copper strands minus the silvering. I have > *measured* the dry RF resistance at 1.83 MHz of a 67 foot length of corroded > #14 stranded plain copper at 62 ohms. When new this wire had resistance at RF > of less than an ohm. I have never found the silvered copper equivalent in > anything remotely approaching that degraded state. > > RG400 wound on the proper core for the job will last a lifetime. > > 73, Guy K2AV > > On Saturday, February 6, 2016, Robert Nobis <[email protected] > <mailto:[email protected]>> wrote: > > > 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] <mailto:[email protected]> > > > > > > > On Feb 6, 2016, at 17:49, Guy Olinger K2AV <[email protected] > > > <mailto:[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. > > > > > > > > > > > > ______________________________________________________________ > Elecraft mailing list > Home: http://mailman.qth.net/mailman/listinfo/elecraft > <http://mailman.qth.net/mailman/listinfo/elecraft> > Help: http://mailman.qth.net/mmfaq.htm <http://mailman.qth.net/mmfaq.htm> > Post: mailto:[email protected] <mailto:[email protected]> > > This list hosted by: http://www.qsl.net <http://www.qsl.net/> > Please help support this email list: http://www.qsl.net/donate.html > <http://www.qsl.net/donate.html> > Message delivered to [email protected] <mailto:[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]
