On Mon, 25 Oct 2010 18:31:16 -0400, John Ferrell
wrote:

About 50 feet north of that tower is my field of 36 radials where I
currently have a 40 meter self supporting vertical. I would really
like to not compromise the radials or the operation of whatever
vertical I choose.

I am thinking of putting the "new" tower about 20 feet West of the
vertical & radial field. The plan calls for 4 sticks of Rohn 25 on a
tilt plate with a utility pole doing the stabilizing. Winches as
required.

Hi John,

Consider the spacing of elements in an array (any, even vertical
arrays that are installed for directional AM stations). The
dimensions there are in the tenths (or less) of wavelengths and
couplings are very strong. You propose a second structure that is
still quite near (about .15 wave) on the basis of this simple metric
alone.

What it does is another matter. It will certainly disturb the
radiator's loading. It will certainly absorb signal. It will
certainly re-radiate that same signal. It will certainly introduce a
phase shift that combines with the original signal. The combination
can either produce a lobe or a null OR it may be unproductive in the
practical sense (all certainties go by the wayside).

One might pause and reflect that the new tower could easily (this is a
hail mary pass) serve as your 40M radiator. Why have two vertical
structures (ignoring that we will actually be talking about the
installation of a THIRD vertical structure if we include the south
tower)?

73's
Richard Clark, KB7QHC