In article ,
Owen Duffy wrote:

Fred, I think the term "OCF Dipole" is usually used today to mean a
dipole fed with coax and balun (often 4:1, usually not 1:1) fed offset
from the centre and often operated at half wave resonance or harmonic
multiples.

...
Using the modeling software, is there a feed-point where impedance is
close to an available balanced feed-line on multiple bands? As close,
I
would accept a 2:1 SWR.

If you are going to use an ATU and open wire line (as distinct from
balanced line) why are you restricting the max VSWR to 2. Practical open
wire lines can operate at much higher VSWR with acceptable losses.

Once you have addressed that question, then ask yourself why you wouldn't
just feed such a dipole in the centre and reduce the common mode current
problem caused by the asymmetric feed.

Owen-

My friends with money used a 4-to-1 BalUn coil with their Windoms and
drove them with rigs such as the DX-100 and Viking II. I think their
Pi-network output stages matched a wider range of impedances than the
modern solid state rigs can match, but I didn't know about that at the
time. I thought the 300 Ohm TV feed-line was a close match to the
antenna, and the BalUn transformed it to a nearly perfect 75 Ohms.

My current interest is two-fold. First, I was curious to know just how
good the match might have been on the old antenna. Second, it would be
handy to have a multi-band antenna that could be fed off-center so the
feed-line didn't have to run parallel to the antenna wire before
entering the shack.

I can afford a BalUn now. A little vertical radiation from the
feed-line would be OK unless there was a problem with RF burns!

Fred
K4DII