One of the old Firestone HF circuits to EL used stacked rhombics to kill the
second lobe. The high angle lobe was hurting RTTY reception because of the
delay associated with receiving via two propagation modes.
Today's modulation methods and computation power would not be hurt by
such multipath propagation.
I have thought of using such a scheme with LPDAs on receiving so as not
to receive US stations so strongly. Most of the hurtful QRM when trying to
work DX comes from first-hop stations. (I am speaking of on-frequency QRM.)
The benefit on transmitting is unimportant.

Lots of fun to use a pair of the 5 element yagis included with EZNEC to
see the effect of vertical (or horizontal) stacking (broadside array).
73, Mac N8TT
--
J. Mc Laughlin; Michigan U.S.A.
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