Each band has its own resonant dipole wire pare.
To feed the balanced dipole from 50Ω coax a Balun is needed. I use a D-Original BU-55 balun for this. Frequency range 3 to 75 MHz. Impedance 50 Ω. Ratio: 1:1. Maximum power 500 Watt PEP.
I build this antenna to have a reference antenna for 20 and 40m.
Placed as a inverted-V every added wire makes a sharer angle at the feed point.
Most Fan (parallel) antennas are made with the longest wire (lowest band) at the top. Highest band at the bottom.
For wind stability I changed the order and placed the 6m band dipole in the middle. Not sure what this does for radiation angle.
As I use flexible spacers the bottom wire needs a little tension. This is accomplished by en extra non metal wire from the end of the bottom wire to the top wire.. This also increases wind stability.
I think non-flexible spacers my be a better solution...
As the antenna is hoisted, a ground connection near the feed point with the mast can't be made.
To reduce feed-line radiation a choke balun or ferrite core can be placed near the feed point. For me three ferrite chokes did the job.
As long as the band is in the range of the balun, any band (dipole) can be added.
Tuning a band may effect other bands. So be careful and cut with care. Measure all bands after every adjustment.
Measuraments SWR & impedance
File names:Fan dipole 99m [SWR|Z|Smith]
LCD2clip to make screenshot (F+6)
Alt+PrtSc and copy to Gimp
FileZilla to ../files/inline-images/