Fresnel Zones & Diffraction

1. Conceptual Intuition (L1)

• Radio waves occupy volume (a football shape), not a thin laser line.
• Blocking this volume reduces signal even if you have "Line of Sight".
• Odd zones cancel, Even zones add (roughly).

2. Engineering Math (L2)

• Calculation of 1st Fresnel Zone radius ($F_1 = \sqrt{\frac{\lambda d_1 d_2}{d_1+d_2}}$).
• 60% Clearance rule of thumb.

3. System Application (L3)

• Knife-edge diffraction loss logic.
• Impact of earth curvature on long links.
• Obstacle height measurements.

Interactive Component: Fresnel Zone Visualizer

• Description: Visualize the zones and obstacle clearance.
• Controls: Tx/Rx Heights, Frequency, Obstacle position.