[TowerTalk] current balun question

[Jim Brown]

On Mon,3/20/2017 5:57 AM, Máximo EA1DDO_HK1H wrote:
> Is the choke balancing I1 and I2 ?

Like Jim Lux said, the choke FORCES balance AT THE POINT WHERE IT IS 
APPLIED by removing the only other path for current, common mode current 
on the transmission line. So a choke applied AT THE FEEDPOINT forces I1 
to be equal to I2.

> And the currents from antenna to ground? Does them count?

You need to study how antennas and transmission lines work. That's 
beyond the scope of an email reflector. :)

Current and voltage both vary along the length of both antennas and 
transmission lines. The ends of an antenna are an open circuit, but with 
capacitances as shown in that drawing. If there were zero capacitance, 
the current would be zero at the ends and the voltage would be infinite, 
but thanks to the capacitance, current is very small and voltage is very 
high.

The method shown in the drawing for feeding a vertical dipole is not the 
only one. See this one

http://k9yc.com/VerticalDipole.pdf

and this implementation for Field Day.

http://k9yc.com/80M-FDVertical.pdf

On Mon,3/20/2017 3:51 AM, Guy Olinger wrote:
> Go buy something MADE FOR the application and frequency. Then string 
> it up and go have fun. 

You otta be ashamed, Guy. :)  Go BUILD something designed for the 
application and the frequency using my Choke Cookbook. k9yc.com/RFI-Ham.pdf

73, Jim K9YC