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ANTENNA PHYSICS 

This section will distill several equations regarding antenna theory and connect the dots using words wrapped around the concepts to enable a complete understanding of antenna theory --- for any technical level.

  

Part 1: The vast difference between electron flow and electric current/displacement flow in a conductor.

To distinguish and visualize the difference between Electron flow and electric current/displacement in a conductor we use the Newtons Cradle instrument --- often considered a toy.  It is used to demonstrate transmission line logic including how waves of electric current propagate in a conductor, impedance mismatch, reflected waves, etc. etc.etc.

A.  Basic mechanics of wave propagation in a conductor.

        1.  Watch this video noting that one bearing is launched at a second resulting in the launched bearing  coming to a stop and the second accelerating to the same speed/energy level as the first.    Video clip 1 bearing slow .  The concept here is, when a bearing is launched at a second  stationary bearing that weighs the same, the first will come to rest exactly the depth of compression plus decompression which is approximately 10 nano-inches and the energy from the first will be transferred to the second.  The displacement current was probably close to 700MPH.   Think of the momentum/velocity as the magnetic energy and the compression the electric field.  Look at 1 bearing of 5.  Each bearing is accelerated contacting the adjacent, compressing decompressing individually and passing the energy to the next while coming to a stop almost in place.

  

  

  

 

CALCULATE CAPACITANCE OF STRAIGHT WIRE:

See page 586 for equation and 609 for table and K factor

 

Video clip 1 bearing slow

Video clip good 1 bearing slow

Video clip 1 bearing 5 total slow

Video clip 3 bearings slow

  

Video Clip of Surge Current as voltage is applied to 54 foot wire. 

  

Schematic update for surge impedance 

Schematic update 2 for surge impedance

  

Measuring the surge impedance with inadequate ground

Measuring the surge impedance and velocity factor of a single wire

  

Measuring the surge impedance of 75 ohm coax with scope probe on feed point and end of coax 

  

Single wire snapshot of surge impedance 

Part 1 final 6  

END FED DISTRIBUTED AND LUMPED

CENTER FED DISTRIBUTED AND LUMPED

Surge impedance in space

  

  

  

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