At my summer QTH I mounted a simple wire delta loop, that I feed with a standard 300-home TV ribbon (I prefer symmetrical antennas, as having a good ground is not always that simple).

In the station I have an asymmetrical tuner, so, not to get RF on my radio, I must use a balun in between the tuner and the 300-ohm ribbon coming from the antenna.

I am not so enthusiast about using a common 1:1 or 4:1 toroidal transformer, as I am not sure on how those transformers behave across the very wide impedance range that they see at the ribbon end when operating 7 through 28 MHz.

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.

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?

Thanks and 73

Tony I0JX - Rome, Italy