From the Lab ...

... Hacking and Slashing since 2002

Title: Log Periodic Dipole Array
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We decided to start the construction of an EMC measurement antenna. So the choice was a Log Periodic antenna - it's basic characteristics are: 
 
- Frequency range: 200Mhz to 3Ghz 
- 23 Elements 
- Tau = 0.86 
- Sigma = 0.065 
- Psi (separation angle) ~ 4 degrees 
- Gain ~ 6.5dB 
 
Construction materials are copper-plated brass rectangle box for the feeders, and brass round stock (tube and solid) for the dipole elements. We'll be going down to MS&T - Missouri University of Science and Technology - (formerly UMR) for testing to determine the Antenna Factor curve. 
 
Pics (Corresponding images are below titles) ... 
 
Milling the holes for the dipole elements - 
scaled.IMG_0755.JPG
 
Finished holes for the dipole elements - 
scaled.IMG_0760.JPG
 
Final raw materials ready for final assembly - 
scaled.IMG_0764.JPG
 
Assembly starting at the high frequency end - 
scaled.IMG_0768.jpg
 
Finished antenna - 
scaled.IMG_0774.JPG 
 
Still need to add mounting sections and the coax/N-connector. 
 
Here's a modified Excel spreadsheet we used for developing some of the basic parameters: LOGPERIO_1.xls.zip 


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