Topband: Parallel vertical antennas and 160M amps

[Jon Zaimes AA1K]

AA4NN:
>On these parallel vertical systems under discussion, are we talking about
>phased vertical arrays or parasitic arrays?  I am confused also about
>having 3 elements switchable in any of 4 directions.  

All three of mine (160, 80 and 40m) will be parasitic arrays. K3LR is using
one of these on 160 meters, and such an antenna was described in ON4UN's
book for 160. That one uses a full-size 1/4 wave driven element, with the
parasitic directors hung off rope catenaries that go from the top of the
tower to distant points on the ground. The parasitic elements are cut as
directors, with a sloping T top section for top loading. There are four of
these spaced around the tower, each out 66 feet from the tower. Only two at
a time are used --- such that two of the parasitic elements are in a line
with the driven element. One of these is grounded and thus functions as a
director. The other is grounded through an inductance that makes that
element function as a reflector. Thus we have a reflector, driven element
and director in line. The two remaining elements are left floating and thus
electrically invisible. With relays, the array can be switched in any of
four directions. Mine uses a slightly "squashed" driven element -- only 100
feet tall.

K0HA also uses parasitic arrays quite effectively.

73/Jon AA1K




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