Topband: power rating of un-un

[Roy Koeppe]

About:

"I a message of another subject I posted the question below. Since I did
not
get any replies, here I go again;

I made an unun using a T-200-2 with a 19 turn bi-filiar winding using 1
mm
enamelled CU wire. How much power should I expect this transformer to
handle?

Are there any good online resources dealing with construction of TX
ununs
and baluns?"


73 de Björn /SM0MDG


Hi Bjorn,

My answer is in general. First, powdered iron is not the choice for a
broad banded un-un. You should be using ferrite, such as a 2.25-inch
ferrite, maybe stacked. Is the transformer used as a step up, or step
down, or 1 to 1? If as a step-up, the requirements are more demanding
because of the higher Z. A 2.25-inch ferrite toroid core with about 16
bi-filar turns, used as 1 to 1 or step-down will handle about 1 kw ssb.
I'd use two stacked 2.25-inch cores with 12 gauge wire for low-Z such as
feeding an INV-L, etc.

73,   Roy    K6XK