I built a pair of 80/40/20 fans set at 90 deg to each other and was
quite happy with them at 65'. Good F/S. I used EZNEC for the design
and it was close, but for the modeling be sure to follow the advice of
Cebik re modeling repeated in the example by Dan at ac6la.com As built,
mine was close enough to the modeling.
For the center insulator I used a 4 x 12 x 3/8" acrylic so the centers
were separated by 5". The ends were separated by 30" with some square
3/8" pvc rod. Parachute cord was used to tie the ends of each dipoles
insulator to the 80m end insulator. This gets to be a real confusing
collection of wire and cord so they get wound up when taken down on a 8"
diameter 4' long piece of concrete form tube.
After being replaced with other antennas at my QTH, the 20m element was
removed and one tuned for cw and the other ssb and they are now club
Field Day 80/40 antennas. Rolled on the tubes, they have gone up and
down for several FD's.
Grant KZ1W
On 10/1/2017 5:50 AM, N1BUG wrote:
I would not recommend a parallel/fan dipole with 80/30 meters. I've
tried it several times and the 80 meters wire detunes 30 meters. The
antenna works as badly as if one simply used a tuner to force power
into the 80 meter wire.
Thanks Joe. That makes sense.
The better "solution" for fan dipoles would be two fans - one for
80/40 and one for 60/30 where one has a harmonic relationship between
the two bands in the antenna.
That would be attractive and reduces ropes considerably over single
band wires. I just need to find a mechanical approach that works.
73,
Paul N1BUG
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