[Antennas] Balanced line optimum conductor spacing?

2002年1月06日 07:53:52 -0500

At 01:59 PM 1/5/2002 -0800, Dan Richardson wrote:
>The correct formula is Z0 = 120*arccosh(D/d) where D is the center-center 
>spacing, d
>the diameter, and arccosh the inverse hyperbolic cosine function. With
>this formula you can see that the impedance approaches zero as the wires
>get extremely close together.
>>Danny,

True Danny, but the formula uses center-center spacing, and the wires will 
never get closer than the diameter of a wire. The impedance of two #26 
enameled wires close spaced is about 100 ohms, for example. Don't laugh, a 
very effective low loss balanced transmission line is a pair of #26 teflon 
insulated silver plated stranded wire twisted once every six inches or 
so. Great for field operations. If you use a 1:1 balun or a 4:1 into an 
antenna tuner like the K2AT in the K2, or a Z11, it's a great 
combination. I used it last summer with a 4:1 home made balun with my K2 
for field trips. You can make the wire a little larger and use high power 
with it for the fixed station.
73, Chas, W1CG