wrote:
I sort of thought that this OCF antenna was typically used for a
multiband antenna, that's typically the 'idea' behind using them.
Keeping that 'thought' in mind, how can you 'optimize' this multiband
antenna for one particular band without 'de-optimizing' it for
others?

Given the SWRs that EZNEC predicts, feeding the OCF
at a current maximum point causes the XMTR (or tuner)
to see the following resistances looking into the
ladder-line.

3.8 MHz, 129 ohms; 7.2 MHz, 120 ohms; 10.125 MHz, 37.5 ohms;
14.2 MHz, 58 ohms; 18.14 MHz, 71 ohms; 21.3 MHz, 51 ohms;
24.95 MHz, 53 ohms; 28.4 MHz, 61 ohms

Let's say you wanted to optimize for 40m. You would
choose a 450 ohm ladder-line length of 67.5 feet and
expect 120 ohms looking into the ladder-line. Use a
tuner or transformer for a perfect match.

Oh, I know that assumes that you can have more than one
antenna, which isn't always the case. So having an 'un-optimized'
antenna is what you'll end up with in most (if not all) bands except
for one. Which is the 'fault' for almost all multiband antennas.
Isn't it?

Not for this one: http://www.w5dxp.com/notuner.htm
That antenna system is efficient on all HF bands.
It is fed with 1/2WL of ladder-line on 80m and 3/4WL
of ladder-line on 40m. Also appropriate lengths of
ladder-line on all other HF bands. The ladder-line
length averages around 100 feet.
--
73, Cecil http://www.w5dxp.com
"According to the general theory of relativity,
space without ether is unthinkable." Albert Einstein