[Antennas] Multiple dipole spacing

Mon, 12 Aug 2002 19:46:50 -0500

Amen to Dave's advice !   (W9LYA)
A lot of grief and labor can be saved by feeding an 80m dipole with ladder
line, tuner &
balun for excellent all band results.   I personally  prefer a link coupled
tuner such as
a Johnson matchbox which eliminates the need for a balun.
"Try it... you'll like it"   hi
73,  Les,   W�OJH

David W Sher wrote:

> I have made several parallel dipoles, most recently a 40/80 using
> ladder-line for the elements and a 20/40/80 with PVC tubing for spacing.
> It has been my experience that the latter arrangement suffers from
> flipping over on itself in a wind, potentially shorting out elements if
> you are using bare wire, unless you restrain the lower elements with
> additional guys.  The ladder line parallel works fine.
>
> Howevwer, why don't you save yourself grief by putting up a single dipole
> fed with open-wire or ladder-line, with a tuner at the transmitter end.
> I found this a better deal all around.
>
> Dave          W9LYA
> What wrought doG hath?
>
> On Mon, 12 Aug 2002 06:10:14 -0700 "R Goodspeed (W7DGX)"
> <[email protected]> writes:
> > Gentlemen,
> >
> > I want to build a multiple dipole arrangement with one single feed
> > point, and the higher frequency dipoles hanging below the lowest
> > frequency dipole. The desired bands are 20 meters, 17 meters, 12
> > meters,
> > and 10 meters.
> >
> > What separation spacing is required to assure no flashover or
> > melting
> > will occur using legal limit power. Is PVC pipe good enough to be
> > the
> > spreaders to maintain the dipole separation spacing. Ten foot
> > lengths of
> > schedule 40 pipe is $1.44. Are one or two feet separations
> > sufficient??
> >
> > From my reading, the spacing must be greatest at the ends of the
> > dipoles, because it is the highest voltage point. Is that true with
> > the
> > other dipoles being connected at the same time???
> >
> > How much interaction should I expect? How would that affect the
> > �normal�
> > length of a dipole?
> >
> > Present plans involve hanging the dipole ends from trees with a rope
> > and
> > pulley arrangement that will allow lower the antennae for
> > adjustments
> > (and repairs if needed).
> >
> > Thanks for reading this.
> >
> > Thanks for any information you folks may provide.
> >
> >            Rolly W7DGX
> >
> >
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