On Thu, 27 Jul 2006 23:29:58 +0200, "Antonio Vernucci"
wrote:

So, I decided to instead use an RF choke that quenches the common mode RF. I firstly built a thick ferrite core by taping together five 3/8"OD ferrite rods, 6-inch long. I then made 10 turns of a very thick insulated red-black twin lead on it. The turns are widely spaced, so as to have low capacitance between adjacent turns.

The system works fine and gives me no problems, but I would like to hear some opinions on that approach, as I do not often see it proposed as a solution for feeding balanced lines.

Hi Tony,

Sounds good. The only unknown is the ferrite properties for the range
of RF.

Should I instead wish to try a common toroidal transformer, would you better use the 1:1 or the 4:1 version? My reasoning is as follows: unless my delta loop resonates on one of the ham bands, its impedance will generally be rather high. So, using a 4:1 balun would facilitate the tuner task. Any comment on that too?

You can also try putting a 1:1 current BalUn (or choke) on the coax
going from your rig to the tuner.

However, you do not say you had any problems to begin with. If you
are trying to achieve symmetry, you need to be able to measure how
close, or how far away you are. If you cannot do this, then you don't
know how much improvement you are making.

73's
Richard Clark, KB7QHC