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

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Presentation on theme: "Basic ½ Wave Dipole Antenna Presentation By: Rodney Davis W3LDR and Chris Mabry KF5QIS Lubbock Amateur Radio Club."— Presentation transcript:

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

2 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

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 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 / 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 ga. Insulated Stranded

8 Suggested Build 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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