"Wayne" wrote in
:

"Owen Duffy" wrote in message
...

....

Mentioning current baluns, you describe a balun that could not be
categorised as an effective current balun, as if you were to ground
the side of the load direct connected to the ATU, the whole thing
fails.

-
Could you state this a different way, as I don't follow the grounded
output reference.

I have written some notes about baluns in antenna systems at
http://www.vk1od.net/balun/concept/cm/index.htm . The notes explain why
a current balun is most suited to 'general purpose' antenna application.

In an ideal current balun, the current in each output wire should be
independent of whether one terminal or the other is grounded.

In the case of the balun describe, grounding one or other output
terminal has a large effect on output current in each of the wires.

Proponents of some balun designs insist that they work perfectly into an
isolated load. Of course, it the load is truly isolated, ie there is not
current path to ground from the load, then they are correct, but you
don't need a balun in that case because since the load is properly
represented by a two terminal network, the current into one terminal
MUST equal the current out of the other terminal. Problem is that real
antennas aren't necessarily will represented by a two terminal network
(though we often talk as if they are).

Owen