I modeled my 80/40/20 fans with the referenced zero length transmission
line (Cebik/AC6LA) with the centers about 4" apart on an acrylic 5 x 9 x
1/4" sheet and the tips 24" apart spread with pvc rods as the only
spacer. Another modeling requirement is to align the segments as best
as possible for closely spaced wires. i.e. make them the same length on
each dipole. So the number of segments per leg is chosen to make that
happen. Also, if the wire is insulated, model with it at the planned
height.
There wasn't any wire cut and try to hit the targeted resonances.
However, there gets to be some handling complexity with the strings to
tension the higher band wires. I used parachute cord from each higher
band dipole to the 80m insulator. That took some cut and try to get the
right tensions. The choke and rg213 weight on the acrylic center plate
helped keep the 80m the top dipole.
I don't know of any reason modeling would not work for an inverted V
geometry as Jim noted.
Grant KZ1W
On 7/11/2018 16:45 PM, Jim Brown wrote:
On 7/11/2018 4:34 PM, terry burge wrote:
But my advice for trying to get 80 and 40 meters to play together in
a fan dipole, inverted V, etc. is don't.
First, my primary antennas for 80 and 40 have been a pair of 80/40
fans at right angles to each other. They are approximately horizontal,
the approximate part being sag in the middle. The two wires are spaced
about 14 inches, using short pieces of 1/2-in PVC conduit with holes
drilled in them for the wires to pass through.
60M may not play well in an 80/40 fan.
I've never tried a fan hung as an inverted vee -- I have plenty of
organic supports, and a flat dipole is superior to the inv vee config.
I don't see any reason why an 80/40 fan wouldn't work as an inverted vee.
73, Jim K9YC
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