Antenna Theory and Line Transformation from DX Engineering

This probably goes to show how much of a nerd I am with Ham radio, but I just read through the 22 pages of Tom W8JI of DX Engineering's PDF "Baluns: Choosing the Correct Balun" and found it a very worth while read. Anyone that operates HF should read through this. There are too many people out there that don't fully understand their antenna systems and line transformation. Admittedly, I only know so much when it comes to the subject but I know I think about antennas, tuners, and efficiencies more than a lot of Hams that toss a dipole in the air, feed it with coax, and slap a tuner and amp on it.

I will hold on to this PDF for sure and use it as a reference. There is too much in this article for me to soak up all at once but I just realized how much I don't understand with the subject. Maybe I am just to the point that I know enough to understand the ideas presented in the article, but getting it to be forefront in my mind will take some application of the ideas to see it first hand.

I checked the manual of my Palstar AT1500CV (now discontinued, replaced by the AT2K) to see what kind of balun it uses - it is a 4:1 Ruthroff Voltage type. From the article Voltage type baluns are not good because they don't handle current well, especially in mis-matched systems. Current baluns are ideal. Another issue with 4:1 baluns, regardless of whether it is a Current or Voltage design, is that the impedance transformation is from high to low. The impedance after the balun is 1/4 of the impedance before it. Tuners do a better job with transforming moderate to high impedances. When you take a moderate impedance and divide it by 4 you now have a low impedance - which is harder, and less efficient, for a tuner to match.

So much to learn and it will only be absorbed in my head so fast. This is the great thing about ham radio - you can think about the subject for an eternity and never learn everything there is.