Hi, Fred. You said: "Guy K2AV I'm guessing you don't like rg58 because of the center conductor moving outwards??"
Nope. :>)) RG58 is not RG400. That's why I don't like RG58. RG400 is what should be used for winding coax on toroids. RG400 is a currently manufactured item. It is INTENDED to handle sharp bends as found in aircraft wiring harnesses (and therefore also handle being wound on toroids). The center conductor is silvered stranded copper, the dielectric is PTFE (Teflon), the shield is TWO dense woven layers of silvered copper braid, and the jacket is PTFE. RG400 is rated to 7 kW. RG400 is Mil Spec. MIL-C-17 27478. Which means that if your house blows up from a gas explosion, the RG400 will still be there working when the fire is put out. Essentially it never ever goes bad or weird unless catastrophically treated, like crushed with a hammer, nailed through, ends submerged in battery acid, or used as a tow rope for something heavy. I have one piece of RG400 that was inappropriately used to arrest the fall of and suspend a linear amp in mid-air. The coax still works, but it looks funny, and it wasn't 50 ohms any more. A Chinese finger trap on the dielectric. The silvered copper conductors in the double shields and stranded copper center conductor will not deteriorate from occasional moist air in the coax and convert it to many small conductors with performance changes, because silver oxide is conductive. The dense silvered copper shield weave, with two layers of shield weave in RG400, makes for extremely good shielding. A lot of RG58 is cr*p shielding, sparse enough to see through, sparse to maximize profit. The PTFE in the jacket and dielectric is a low loss material, will not deteriorate from ultraviolet. PTFE will not gradually shrink or crack by leaching its chemical components. The jacket and dielectric will not melt and ruin a connector when you solder it, or when you forget it's there and put 1500 watts on it. PTFE is a highly robust and predictable material. The PVC jacket formulation on RG58 could be just about anything. People have discovered that jumpers and leftover pieces of RG400 can be sold on eBay. So you can pick up a ten foot piece of RG400 for less than retail. I like the pieces with a male BNC on one end. I hate doing BNC connectors. Brand-new coils of 100' plus can occasionally be had for as little as 1.80 USD per foot, and regularly for 2.30 USD per foot, on eBay. For all intents and purposes, a toroid wound with RG400 is a permanent device, lifetime depending on the toroid instead of the coax. You should buy enough RG400 so RG400 is the small coax that's "laying around" and still good as new to do a project with, even if you bought it 20 years ago. You can put your lifetime stash of RG400 in your will, and leave it to a younger local ham, who will appreciate it. :>)) RG400 is also K9YC's choice in his new http://audiosystemsgroup.com/2018Cookbook.pdf. Check out the monster common mode blocking choke wound with 23 turns of RG400 over a 4" OD, 3" ID, inch thick #31 ferrite toroid. THAT'S a choke. 17K ohms resistive on 160. 73, Guy K2AV On Sun, Jan 20, 2019 at 12:36 PM <[email protected]> wrote: > Hello everyone. > > I also trying to improve things here on 160 and other bands. > Going to make a few chokes. > I have wound 8 turns thru 2.4 x2 31 mix but haven't seen any real > improvement. > Trying to get rid of some birdies. > > Guy K2AV I'm guessing you don't like rg58 because of the center conductor > moving outwards?? > > 73 Fred KB4QZH > > > _________________ > Searchable Archives: http://www.contesting.com/_topband - Topband > Reflector > _________________ Searchable Archives: http://www.contesting.com/_topband - Topband Reflector
