Thanks for your comments, Dave.
Paul, I have been running some tests with twin coax feed as a balanced line
and when I compare it with a dipole fed with 450 ohm line no one can tell
the difference. have you been able to determine the what losses may occur
with it? I am using it to feed a 160 m dipole as a multiband center fed,
and it is tuned with the balanced tunner from QST a few years back. I
would appreciate any feed back you have.
Dave, I have not dtermined the losses which may occur using this system. I
would guess that the losses are higher than that of open balanced line, but
lower than that of a single unblanced coax feedline......I know from my
experience, just as you have, that there was no real difference when
compared to open 450 ohm line. The balnced coax feedline was more
convenient because I didn't have to be too concerned about where exactly I
ran the feedline when in the house (near copper heating pipes, wires,
When I was using the system (I am using a Carolina Windom antenna, now, fed
with coax) a year ago, I wanted to keep my system as balanced as possible.
So, what I decided to abandon the voltage 4:1 balun on my MFJ tuner, and I
did not have a balanced tuner. So, what I did was isolate my tuner from
ground, used the chassis of the tuner as on end of the balanced line, and
used the long wire connection as the other end of the balanced line...then,
to preserve the balanced system, I installed an RF ***(Isolator from
RADIO WORKS) between the tuner and the radio...
THIS WORKED GREAT, and I had NO rf radiating in my house off the feedline,
no RF on the chassis of the radio, NOTHING. I had a truely balanced
system! Comparing this to using just the 4:1 (voltage) balun built into
the tuner, there was no contest!!! This was the first time during my ham
career that I had no TVI problem.
Thanks for your reply, Dave....