Greeting Antenna Gurus,
Put the finishing touches on a 100% homebrew K1WA/(K8UR) K3LR type 5-dipole
sloping dipole (all parasitic) array for 15m only hours before the contest
this weekend and came away quite disappointed.
NE/NW/SE/SW dples are all spaced at 90* from one another but the 5th dipole
(south) is squeezed in between the normal SE and SW directions. Maybe it's
too close. Carib stns were louder when beaming AFRICA than they were when
beaming south. This was all weekend, so I don't think it was an anomaly. I
haven't done field strength pattern testing yet (no time) but I know it
won't be pretty. My little A3S at 24' was usually louder on 15m than the
array. (not 100% of the time, but most of the time.)
This is built almost EXACTLY like Tim's 4-element 160m array at K3LR (or
like his array was in the 1990's anyways - not sure if he still uses it.)
except I used the 5th dipole due south for Caribbean/SA and my 5 radials are
on the ground, and not raised. Phasing lines, tops with ropes, etc. all the
same. Most of the mast is PVC (except the bottom 12'_) and the bottoms of
the dipoles are off the ground maybe 6' (not overlapped at the tower bottom
like Tims). Box and coax grounded, radials attached. All per his article.
What I would like to know from anyone that has either built one for 10-15 or
20m (or any band, and I'll do the math) is what is the actual spacing used
dipole center to dipole center?
Or anyone that knows antenna modeling programs, can you see if this has any
useful gain or F/B with only 6.66' spacing at the centers at 21.1MHz. (which
is roughly 0.142WL I believe)
I went this close because all the hardware was taken from an old 6m array
that I used many moons ago.
I am thinking I should rebuild it with a much larger spacing, maybe around
.25WL(11.6') and ditch the south and extra, 5th dipole.
Tnx
Mike VE9AA
Mike, Coreen & Corey
Keswick Ridge, NB
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