HF Antenna Basics

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HF Antenna Basics
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HF Antennas

• 3 Main Components
• Feed Line Usually Coax
• Carries RF Energy from Radio to Antenna
• Tuner/Coupler
• Couples Feed Line to Antenna -or-
• Couples the Transmitter to the Feed Line
• Antenna
• Radiates RF into the Air
• Setting up a Good HF Antenna is the Key to
  Success!

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Feed Line

• Coax (50 Ohm Typical)
• RG58, RG8X, RG8/213, LMR400, Etc.
• Easy to install
• Typical output for modern radios

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Feed Line

• Twinlead/Ladderline
• TV twin lead, 450 Ohm Ladderline, etc.
• Lower loss than coax
• More challenging to install
• Transition can be made from coax to ladderline

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Antenna Tuners

• Two Basic Types
• Transmatch Matches the Transmitter to the
  Feed Line.
• Most Common, But Generally Least Efficient
• Feed Point Coupler Matches the Feed Line to the
  Antenna
• More Difficult to Set Up, But Generally Most
  Efficient
• Note A Resonant Antenna Requires no Tuner and
  Results in a Very Efficient Configuration

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Antenna Tuners
Antenna

• Transmatch Tuners

Transmitter
Tuner
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Antenna Tuners
Antenna
Coupler

• Feed Point Couplers

Transmitter
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Basic Antennas

• There are Hundreds of HF Antenna Designs That
  Work, But We Will Cover a Few Basic
  Configurations
• Dipole
• Long Wire
• Vertical

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Dipole Antenna
½ Wavelength or 468/f (MHz)
Dipoles May Operate on a Second Band (Antenna
Tuner Suggested) For Instance 40M Dipole on
15M 80M Dipole on 17M
A Resonant Dipole Requires No Tuner for Single
Band Operation
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Dipole Antenna
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Inverted V Dipole
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Multi-Band Dipole (Fan Dipole)
Multiple Bands, One Coax, One Balun
Note Come to Field Day and See the MMARC Field
Day Dipole
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Dipole Variations

• Ladder Line Fed Dipole (Multi-Band Dipole)
• Off Center Fed Dipole (i.e. Carolina Windom)
• Rotatable Dipole
• The G5RV Antenna
• Extended Double Zep

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Long Wire Antenna
or Use 41 Balun Here and Use a Transmatch Tuner
in the Shack (But Keep Your Coax as Short as
Possible)
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Basic Vertical Antenna
¼ Wavelength Or 234/f (MHz)
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Basic Ground Plane Antenna
¼ Wavelength or 234/f (MHz)

• For Instance
• 20 Meters (14.1 MHz)
• 234/f 16.6 Wires
• Top Insulator At Least 35 High

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Baluns

• Many Types, But Two Most Common
• 11 Current Balun
• Typically Used at Feedpoint of Dipole or Ground
  Plane Antennas
• May Also be Called a Choke or a Line
  Isolator.
• 41 Balun
• Transition From Coax to Ladder Line
• Unbalanced or Long Wire Feed Points

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Antenna Supports

• Trees
• Wood Pole
• Steel or Aluminum Pipe
• Fiberglass Pole (i.e. Flagpoles)
• PVC Pipe
• Roof Tripod
• Chimney
• Various Commercial Mounts
• Tower

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General Tips

• Always Be Safe on Ladders, Roofs, in Trees, etc.
• Stay Away From Power Lines!
• Do More Reading and Research
• Be Aware of Covenants/Restrictions and Ordinances
• Ask For Help from MMARC Members
• Dont Spend a Lot of Money on Antenna Wire
• 14 or 12 Building Wire (THHN) Works Well
• There is Nothing Magic About Antenna Wire
• Do Buy UV Resistant Dacron Rope
• Cut Wire Antennas About 6 Longer Than Needed and
  Trim Them to Resonance