[TowerTalk] Balun Question

[Jim Brown]

On Fri, 6 Aug 2010 11:12:07 -0500, Cycle-24 wrote:

>What do people use out there for 1:1 baluns on their dipole or Yagi
>antennas? 

I use exclusively coaxial chokes wound on ferrite cores. See my Choke 
Cookbook and the associated discussion in 

http://audiosystemsgroup.com/RFI-Ham.pdf

>Is there any real difference between using cores, beads, or air
>wound coaxial baluns?

Yes, there are MAJOR differences. As Steve observes, the choke should be 
RESISTIIVE, not inductive, a HIGH VALUE of resistance is needed to handle 
high power, and Fair-Rite #31 and #43 core materials are the weapon of 
choice. 

For applications up to about 500W, a parallel wire (bifilar) choke on a 
single #31 core is quite effective, but depending on feedline length and 
antenna imbalance, might overheat at max ham power levels. 

Again, study specific winding instructions in that tutorial. 

73, Jim Brown K9YC