On Mon, 22 Oct 2007 19:06:40 -0400 (EDT), firstname.lastname@example.org wrote:
>Faced with this question several years ago, I made a 15 meter dipole
>out of #14 solid copper 600V THHN wire. I strung it up between a
>tree and a wooden pole, about 20 feet off the ground. I checked
>the resonant frequency. I then lowered the antenna, stripped the
>insulation off the wire, and repeated the exercise. The difference
>in resonant frequency was almost exactly 3 percent. Since then,
>I've observed that THHN wire always makes a difference of between
>2-3 percent from formula, depending on wire size,manufacturer, and
>whether solid or stranded.
>Not the most scientific approach,
I'd call that VERY scientific -- you set up a controlled experiment and
carefully measured it! The only way to improve your science would be to
measure a lot of antennas and a lot of wire types and wire sizes. But
what you've done was right on, and quite helpful! Thanks.
TowerTalk mailing list