Wow! It is really great when something simple works. Yes, 6 bifilar windings
work really great. Even better the impedance measurements worked as expected.

Now I need to design 2:1 and 4:1 impedance matching transformers for 500 watts.
Those are in anticipation of successfully resolving the ground of the antenna
system.

Thanks - Dan

Frank wrote:
Dan, I think #43 is powdered iron, which is fine for high Q inductors, but
not very good for broadband transformers. As has been mentioned by others;
a ferrite core with bifilar windings should do it. Check out:
http://www.oselectronics.com/downloa...ansformers.pdf for more
info.

Frank


"dansawyeror" wrote in message
. ..

All,

I am trying to measure impedance through a balun, or more accurately a 1:1
in line "transformer". For test purposes the transformer is two windings
of 10 turns each on a toroid. The winding are tightly wound on opposite
sides. The material is #43, the toroid is 3/4 inch OD.

If I drive one side of the transformer with one milliwatt at 4 MHz and
terminate the other side into 50 Ohms, and then measure the input voltage
and the output voltage. The output voltage significantly less then the
input voltage, about 1/3.

The second measurement that does not support my understanding is: If I
connect the transformer up to an 8450A through appropriate couplers, and
then short the output the 8405A does not show a 180 degree phase shift
between 'open' and 'shorted'. If this measurement is made without the
transformer then the results are as expected.

This is obviously something with the transformer. I would like to
construct a simple 1:1 in line transformer good from 3 to 30 MHz and 100
watts. What core size, material, and windings are a good starting point
for this?

Thanks - Dan - kb0qil