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Basic ½ Wave Dipole Antenna

Basic ½ Wave Dipole Antenna. Presentation By: Rodney Davis W3LDR and Chris Mabry KF5QIS Lubbock Amateur Radio Club. The ½ Wave Dipole Antenna. Benefits: Easy to build 2.1 dBi Gain Typical Direct Coax Feed Portable or Fixed Location Use Great for State Side and DX Contacts.

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Basic ½ Wave Dipole Antenna

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  1. Basic ½ Wave Dipole Antenna Presentation By: Rodney Davis W3LDR and Chris Mabry KF5QIS Lubbock Amateur Radio Club

  2. The ½ WaveDipole Antenna • Benefits: • Easy to build • 2.1 dBi Gain Typical • Direct Coax Feed • Portable or Fixed Location Use • Great for State Side and DX Contacts

  3. Dipole Fundamentals • A dipole is an Antenna composed of a single radiating element split into 2 sections. Not necessarily equal lengths. (However for Our Build it WILL Be) • The RF power is feed into the split • Radiators DO NOT Have to be Straight

  4. The ½ Wave Dipole • The length is approximately ½ wave • Self impedance is 40-70 ohms (Considered a good match to coax) • Directivity 2.1 dBi • SWR Bandwidth is approx 5% of tuned Frequency

  5. ½ Wave Dipole Typical OAL Length per Band

  6. How to Calculate Length of Antenna Simply Divide 468/Frequency = Total Wire Length Total Wire Length / 2 = Each Dipole Leg Length 468 / 7.190mHz = 65.09ft 65.09 / 2= 32.55ft Add 1ft Extra wire to Each Leg for Tuning approx 331/2 ft

  7. Wire Considerations • Solid vs. Stranded • Solid Can and Usually will BREAK due to winds and movement. Subject to Corrosion. • Stranded More Forgiving and Last MUCH Longer • Most Popular wire size is 12-14 ga. Insulated Stranded

  8. SuggestedBuild Materials • 14ga Insulated Stranded Wire • 2 – Insulators (PVC, Plastic, Ceramic or Glass) • Dacron or Quality UV Resistant Rope

  9. Suggested Build Materials for Center • SO 239 Bulkhead Connector and Small Piece of Coax • 2” PVC 4-6” Long (Longer if Building Choke Balun) • 2” PVC Cap • 2” PVC Plug • 2” PVC Coupler • ¼” Stainless Eye Bolt x 3 • #8 Stainless Machine Screws x2 1 ½” Long, 2 - #8 Nuts, 4 - #8 Washers and 2 - #8 wing nuts (All Stainless)

  10. Dipole Installation • A Dipole may be erected between 2 supports or with 1 support • A Dipole using one support is known as an Inverted-V • The legs of the Dipole may also be bent to form a Inverted U. The bend should be at least half way to the end of the wire.

  11. NOW WITH THE BUILD

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