Or, you could simply use copperweld and forget about stretching. RF Connection sells a fairly flexible stranded and insulated (black poly-ethelyne) wire that, if I remember correctly is 13 gauge.
I built a four band dipole * a few years ago using those aluminum swaged wire clamps. It's still up and to my knowledge, has not stretched or de-tuned. 73, Charlie k3ICH * Two wires from each center balun connector. The upper wires have 75 M traps for 75/160M and the lower wires have 40 M traps for 40/60 M bands. -----Original Message----- From: Elecraft [mailto:[email protected]] On Behalf Of Jim Hoge Sent: Thursday, February 11, 2016 5:58 PM To: Elecraft Reflector <[email protected]> Subject: [Elecraft] how much to stretch copper wire I drew the wire for my first antenna about 40 years ago. That was for a quad utilizing solid copper. Since then,I have made numerous dipoles, all using stranded THHN or THWN 12g wire. My method has always been to anchor one end to a tree or a bumper hitch and hold the free end with a pair of Vise grip pliers. The advantage of the armstrong method is you can feel the draw and sense when it nears its limit. The force require to continue drawing the wire escalates and then failure occurs. In practice, I lay out a tape measure on the ground beneath the wire to be drawn. Once I have my rough length of wire, I will draw it about 10% more in length. (Example: 1/4wave for 7.010 mHz is 33.3' so I will draw to about 36.7'.)This has been enough to prevent additional stretching once the antenna is up in the air. The thermoplastic insulation degrades well before the wire fails and my oldest antenna up at the moment is my 40m dipole, it's about 12 years old. 73,Jim W5QM ______________________________________________________________ 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]
