"rhymer" wrote in message
...
What is the best way to use one feed line for more than one dipole?
Or, is it better to use a coax switch in the shack?

Thanks, Ron

Ron,

Connecting two *dipoles* to the same feedline works just fine. Just tie them
directly to the same balun. There will be two kinds of interaction: first,
the two are electrically in parallel, and second, the wires themselves could
have mutual coupling. The first seems to not really be a problem, and the
second is minimized if there is separation between the two dipoles. For best
results, put them at right angles to each other; if that is not possible,
have at least 15 - 30 degrees separation, either vertical or horizontal. For
instance, you could have a dipole supported at the ends, with an inverted V
hanging below it.

The most interesting case is for antennas at 75 and 80 meters. You get 2:1
SWR from 3.5 to 4 MHz in a virtually non directional antenna (if the two
dipoles are at 90 degrees).

I presently have a 40 m inverted V hanging below an 17 m dipole. (The trees
are too close to do it the other way). The 40 meter is also out of plane to
miss the trees. Works great.

Since you have to trim the lengths slightly (lowest frequency first), it is
simplest to run EZNEC or some other simulation first.

Tam/WB2TT