On Mon, 12 Jun 2006 23:40:19 GMT, "Jerry Martes"
wrote:

I did measure the impedance across a loop of RG 223 with 4 tubes around
the outside. The problem I come up with is my ignorance of *whats needed*
for adequate decoupling of the balanced antenna from the outside of the
coax.

Hi Jerry,

Just think of the antenna as the "source" and consider its
characteristic Z. Now consider the common mode circuit of the
transmission line and its Z. So often this is an unknown, and if we
were always lucky, it would be a half wave multiple to present a very
high Z indeed. Thus 'twould be the end of the story.

How high is high enough? I offer three values for choking:
3 times antenna Z at a minimum;
5 times is practical;
10 times is lab grade.

So, tell us what those 4 tubes measured?

73's
Richard Clark, KB7QHC