[BC] Counterpoise Ground System

[Cowboy]

On Friday 22 September 2006 10:29 am, Bailey, Scott wrote:
>WOW, back then, if your ground system was connected to the city's water
>main, you would have a ground system all over the city! 

 No, actually !

 The radials make up the ground plane.
 One way to think of it is as the other half of the vertical dipole splayed
 out on the ground, changing the geometry and some aspects of the radiator
 in how it launches a wave. The radials are still part of the resonant system.
 In an elevated system, since the radials are 1/4 wave long, it becomes easy
 to see why they have high voltages at the far ends, just like the top of the
 tower. High voltage, low current, just like both ends of a 1/2 wave dipole.
 Anything beyond about 1/2 wave from the feed point becomes irrelevant
 as a part of the RF radiator.

 Ground rods, and in the case sited the city water system, would help as
 a lightning ground. Someplace to dissipate the megavolts and kiloamps
 of a lightning strike, but not as a part of the RF antenna at all.

 In fact, with the gigawatt-seconds of energy involved, even PVC water systems
 would make an OK ground for lightning. The conductivity of the water is
 sufficient, until it vaporizes of course.

> No wonder WROZ had a good signal!

 That city water system wasn't it, whatever it was.

-- 
Cowboy

http://cowboys.homeip.net

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