On Mon, 12 Apr 2004 18:30:18 -0000, (Dave Platt)
wrote:
Of course the driven element would be on the same side of each (but by
using opposite sides, the second antenna could be pointed near
directions we wanted to null out?)

No, I don't think that would work well. That would result in the
second antenna having maximum signal pickup for the signals arriving
from the "null" direction. The antenna pointed towards the desired
source would have a much lower signal pickup from the "null"
direction, and even if the signals from the two antennas are out of
phase you'd find that their amplitudes don't match, and they would not
cancel out well.

A better approach is to aim both antennas at (or nearly at) the
desired transmitter. Put them in positions as indicated above, so
that the signals from the desired transmitter are in-phase.

Hi Guys,

If the goal is to reduce interference, aim the best null(s) at the
offending station and accept the combined mediocre peaks for the
favored station. The signal to interference ratio may be more
important than actual desired signal strength. Two antennas NOT
pointing directly at the favored station may combine enough signal to
allow optimizing the null. This probably has more combinations than
simple boresight aiming, and may yield non intuitive yet useful
results.

73's
Richard Clark, KB7QHC