Topband: two wires Beverage

Jim Brown jim at audiosystemsgroup.com
Tue Jul 27 10:49:12 EDT 2004


On Tue, 27 Jul 2004 07:33:53 +0200, Ryszard Tymkiewicz wrote:

>The similar line used in French Army has Jacques F6BKI and in
> both cases the impedance was about 150 ohm.

When you're thinking about the impedance, remember that this is the 
impedance of that line when used as a twisted pair transmission line. That 
will NOT be the impedance of a Beverage antenna that you build using 
that wire -- in fact, the impedance of the Beverage will likely be pretty close 
to what it would have been if you had used a single conductor of the same 
electrical size (that is, something on the order of 400-600 ohms, 
depending on how you rig it with respect to earth). The beauty of using the 
wire you suggest is that it has robust construction. 

One other point, and maybe others can comment. If the cable is a twisted 
pair, the twisting may cause the electrical length to differ from that of an un-
twisted wire. 

Jim Brown  K9YC




More information about the Topband mailing list