Vytenis:
In my earlier years as a Ham (late 1960s) I had a 3-band dipole for
80/40/20M in my parents' small back yard. The wires for each band were
separated by about 2 feet at the end insulators. Height above ground for the
80M wires was about 8 meters. I was able to use it for very close in QSOs on
80M AM phone and CW, but I worked some amounts of European DX on 40M and 20M.
Years later, after I married, I had a similar two-wire antenna in my apartment
attic for 40M and 20M. The wire ends were separated by only a few feet in that
design, too. Height above ground was about 10 meters. I also worked a good
share of DX with this antenna.
For the first antenna at my parents' home, I used a homebrew tuner. I was
able to match the second antenna's impedance just fine on its 2 bands with the
tune and load controls on my tube-model xcvr (Drake TR4CW.) Both antennas had
the wire connected to the center conductor going in the same direction. I did
not cross them as you were suggesting.
My suggestion would be for you to install the three wires on the center
insulator at the same time, but optimize the shortest (highest freq) antenna
first for minimum SWR. Then optimize the longer antennas in turn. You also
can install the wires in the same plane, spreading them out like a bicycle
wheel's spokes. But keep the wires for one band at 180 degrees from each other
so you don't disturb the dipole operation.
Good luck.
73 de
Gene Smar AD3F
On 03/26/15, LY2KZ wrote:
Hello gentlemen,
I'm considering one antenna for domestic - continental contacts. I'm
curious about all pros and cons of this construction and possible
pitfalls. That is a fan dipole having three wires. Something like here
http://www.hamuniverse.com/multidipole.html One wire is for 7100kHz,
another for about 3800kHz and third for 3550kHz. My idea is to have two
bands covered in full. Is there anyone who has had experience with fan
dipoles? What should I keep in mind before starting to build? Yes,
tuning perhaps will not be very simple, but hopefully I will manage.
How far apart wires should be? 10in OK?
Should all center conductor legs go to the same side or vary left -
right - left
This will be low hanging antenna 10-15m. For DX contacts there will be
another antenna.
Thank you
Vytenis LY5T
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