wrote in message
...
Jeff Liebermann wrote:

snip


FYI I spent an afternoon with EZNEC exploring fan dipoles.

What I found was the farther apart the wires, the less the interaction,
which is what one would expect from common sense.

From my limited runs it appears that somewhere around 20 degrees is about
where the minimum separation needs to be for practical length adjustments.

At angles less than that be prepared to spend a lot of time pruning.

It doesn't matter if the wires are separated vertically or horizontally
other than horizontal separatation means you need lots of support points.

If the bands are too close together, i.e. 20-17, 17-15, 12-10, you can

I had a 10-20 fan dipole laying on a roof for a while. Matched OK after a
bit of pruning but I abandoned it when I found both bands were better with
antennas that were clear of the roof.

I wonder something (and I suppose I'll have to try it, now) : Say I had a
20m horizontal dipole up at 30 feet, could I feed it through a coax that had
a Tee-connector located 22 feet up and simultaneously feed a 15m antenna
from that Tee-connector?

Just as they would be in parallel as a true fan dipole with a common feed
point, so also would they be in parallel -- just not sharing a common feed
point.

Normally I avoid Tee-connectors because they introduce the Evil Mismatch but
this time ...

I can see one problem already; some of the 15m energy that divides at the
Tee-connector would go up to the 20m antenna and be partially radiated and
partially reflected. Standing waves. The coax length would alter the
effect.

"Sal"