[TowerTalk] Fan dipole

[Gene Smar]

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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