In rec.radio.amateur.antenna you write:
Wasn't mine..It was one they were using at a field day. As far as I could
....[snip]....
But usually my preferred multi band antenna will be paralled dipoles,
with the legs spread apart as far as possible.. Fed with a single coax
feed. Thats what I use here at home. No loss in system efficiency
compared to many other multi band designs.

Maybe you can suggest why our formula-cut paralleled-dipole didn't
work all that well at our last "Kids Day at the Mall" effort:

Using some 4-foot-high decorative pillars about 15 feet outside the
mall doors as base mounts, we were able to erect and guy two 25-foot-high
metal masts about 40 feet apart. We then pulleyed-up a 10/15/20 meter
coax-fed parallel-dipole (20m on top, 15m on bottom, 15m between) with
the ropes to each dipole spread about 2 feet at the masts.

VSWR was something like 6:1, although a "tuner" brought it down to
where the radio worked OK. We made lots of contacts, but still
haven't determined why the "raw" VSWR was so high. Any ideas?

Sure. Coupling between the elements being they are so close
together, and inline with each other.
Thats why I spread mine apart as far as possible. The wider apart,
the less coupling in general.
If two dipoles are at right angles, they is almost zero coupling.
In such a case, I've had a leg of one of the dipoles fall down,
with little change in SWR for the other band being used.
Also the wider apart, the less skewing of the pattern from a
normal dipole pattern.
You can use the type antenna you describe, but tuning is tricky.
You have to start with the lowest band, get it tuned, and then
add the next higher band, get it tuned, and so on. Thats about
the only way you will get one tuned for each band.
And I've seen weird things happen with close coupling. I've
had cases where I would have to increase the length of the
legs on a higher band to go *up* the band. Pretty weird..
With them spaced as far apart as possible, you don't have
to go through all that tuning torture, and the antenna will
act more like a normal dipole for each band used.
I've used that system here at home for years. I change it
up quite a bit depending on season, etc..
Right now, it's a turnstile on 80m, and a dipole on 40.
At times, I'll have it 160,80,40 , and others 80/40/20..
Just depends what I'm doing at the time.
MK