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eHam Forums => Antennas, Towers and more => Topic started by: KJ6TSX on April 20, 2019, 01:35:19 PM



Title: VHF antenna distance from mast
Post by: KJ6TSX on April 20, 2019, 01:35:19 PM
I have a Hex beam on a 1 1/4 mast at about 35 feet above ground and wanted to hang a "DR. Fong"  J-Pole antenna off the side of the mast at about 30 feet. How far should the antenna be from the mast horizontally?

Thanks
George


Title: RE: VHF antenna distance from mast
Post by: K6AER on April 20, 2019, 10:15:48 PM
About a 1/4 wavelength and you will have a little gain in that direction. There will be a bit of a null on the opposite side. The farther the antenna is mounted from the mast the less interaction there will be.


Title: RE: VHF antenna distance from mast
Post by: N8EKT on April 21, 2019, 01:47:16 PM
1\4 wavelength will give a directional pattern
1\2 wavelength will give a bi-directional pattern
1 wavelenth or more will produce a more omni directional pattern