[TowerTalk] Baluns/tutorial/notes applied to the AV640

[Jim Brown]

On Sat, 22 May 2010 18:49:02 -0400, Roger (K8RI) wrote:

>So if I take to "individual" current baluns wound on #31 mix and connect 
>the inputs in parallel with the outputs in series, I have two 
>independent chokes with no common magnetic field serving as a 4:1 
>balun.  Even though the chokes may be in very close proximity and even 
>on the same axis with say a half inch to inch spacing between them they 
>are still independent as the flux is contained almost entirely within 
>each individual core. 

Yes. 

>If I understand that correctly that is the 
>difference between the Guanella balun and the experiments run by W8JI?

That series/parallel configuration is a well established design by 
Guanella (from the 60s, I think). An important part of that balun is the 
design of the common mode chokes that make up each leg. What I've been 
talking about here with Steve is using chokes in that circuit that are 
each 5K ohms resistive over the operating range. This provides excellent 
choking action and rather low dissipation. 

73,

Jim K9YC