BTW, the general shape of your real part of Z looks extremely similar to my
overall curve. You obtained about 2k more CM resistance, but the shapes
are nearly identical.
Dave - W?LEV
On Sun, Jan 17, 2021 at 5:35 PM David Eckhardt <davearea51a@...>
wrote:
1. Does your data represent |Z|, or is it the resistance of the CMC
impedance? (Note that I'm plotting the resistance, because, to me, this is
the more important parameter of a CMC).
I am plotting CM resistance. As you wrote, this is what the choke is
placed in the transmission line to accomplish. The initial job of any CMC,
current choke, or single layer air wound solenoid is to prevent CM current
from flowing on the feedline (outer surface of the braid with coax). A
true CMC choke also through the interaction of currents in the two
conductors and the induced magnetic currents in the core assure equal
amplitude with opposite phase on the output of the choke. The current
choke or single layer air wound solenoid can not accomplish this second
operation. This is especially important for those who use open wire,
parallel conductor, and/or window line as feeders, which I do.
2. How did you wind your CMC? (I used wha
t I call a "crossover" technique that was described in Ham Radio Magazine:
"Simple and Efficient Broadband Balun", by Joe Reisert, W1JR, in the
September, 1978 issue). See the attached drawing...
I do not cross or twist my windings. They are flat bifilar windings of
the noted conductors. I'll attach a picture of the last choke I would
yesterday and documented last evening to this group.
Dave - W?LEV
On Sun, Jan 17, 2021 at 2:56 PM Jeff Anderson <jca1955@...>
wrote:
Hi Dave,
Looking at your data, I see that it differs from my plot of 12 turns of
#14 twisted pair on the same type of core (see attached plot). I would
like to detemine why, so a couple of questions...
1. Does your data represent |Z|, or is it the resistance of the CMC
impedance? (Note that I'm plotting the resistance, because, to me, this is
the more important parameter of a CMC).
2. How did you wind your CMC? (I used what I call a "crossover"
technique that was described in Ham Radio Magazine: "Simple and Efficient
Broadband Balun", by Joe Reisert, W1JR, in the September, 1978 issue). See
the attached drawing...
Thanks!
- Jeff, k6jca
--
*Dave - W?LEV*
*Just Let Darwin Work*
--
*Dave - W?LEV*
*Just Let Darwin Work*
