At 6Y4A in the 1997 ARRL CW contest we also used parasitic vertical arrays for
40 and 20m. I was a bit skeptical about parasitic vertical arrays until I used
these arrays... they were GREAT performers (the seafront QTH helped). The
array designed by N6BT of Force12 and was easy to tune with the MFJ antenna
analyzer. The arrays went up in a few minutes. The arrays were maximized for
a 50 ohm match. The trade off for F/B or max gain was not critical for our
criteria, and the extra fraction of a dB you could get was not worth it as
compared to the ease of loading the antenna.
A 2 ele parasitic vertical array will have a very wide beam width, something on
the order of 100 degrees (I forget the actual 3dB points). Much wider than a
typical 2 ele horizontal array. The 6Y4A arrays were fixed at 340 degrees, but
we were able to attract unbelievably deep EU pileups on both bands.
As a comparison, we had a 2 ele wire beam on 20m up around 40' also fixed at
around 340 degrees. The 2 ele 20m vertical array was usually a few S-Units, to
MANY S-Units better than the horizontal array, even for close-in contacts.
Your mileage may vary.
73, Kenny K2KW
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